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  • 1970-1974  (551)
  • 1965-1969  (352)
  • 1920-1924
  • Biochemistry and Biotechnology  (853)
  • pharmacokinetics
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 407-414 
    ISSN: 1432-1041
    Keywords: Diuretic ; indapamide ; human pharmacology ; toxicology ; pharmacokinetics ; TLC assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacology, toxicology and kinetics of a new diuretic indapamide, have been studied in six normal volunteers following a single oral dose of 40 mg. Pronounced diuresis was found, commencing three hours after ingestion, with a peak urinary flow at four to six hours, and continuing for a total of thirty-six hours. A fall in systolic standing blood pressure occurred twenty four hours after ingestion, coincident with the period of maximum dehydration. Free water clearance rose, accompanied by increased urinary losses of Na+, K+ and Cl− and alkalinisation of the urine comparable to the actions of benzothiadiazines. Total urinary losses of Ca2+, Mg2+ and PO 4 3− rose in spite of a fall in urinary concentrations of these ions. The Ca2+ effect compares with the acute ionic effects of other diuretics. No renal, hepatic or haematological toxic effect was demonstrated. The blood sugar level was not disturbed. Serum uric acid rose to abnormal levels although the change did not reach statistical significance. — A thin layer chromatographic method, with a sensitivity limit of 0.1 µg/ml., has been developed for the assay of indapamide in urine. The urinary excretion rates of the volunteers measured over forty-eight hours indicate that the drug is rapidly absorbed with a peak excretion, 2.9±1.3 µg/min occurring three hours after ingestion. The drug is eliminated bi-phasically with an initial short rapid elimination followed by a slower exponential decline with a mean elimination half-life of 10.3 ± 3.9 h. The mean urinary excretion of unchanged indapamide over forty-eight hours was 4.4±1.4% of the administered dose. — It is concluded that indapamide is an effective long-acting diuretic with comparable action to the benzothiadiazine diuretics, but without an effect on blood sugar level in single doses in normal subjects. In contrast with other diuretics, indapamide appears to be extensively metabolised in man, and its longer duration of action to be related to a longer elimination half-life.
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  • 2
    ISSN: 1432-1041
    Keywords: Oral antidiabetic drug ; butylbiguanide ; pharmacokinetics ; two-compartment open model ; plasma concentration ; liver concentration ; intestine concentration ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 50 mg14C-Butylbiguanide was administered intravenously to 4 diabetic patients and 100 mg14C-butylbiguanide orally to 5 further diabetics. The concentrations of the drug in plasma, intestinal fluid, intestinal epithelium and liver tissue were determined and the renal excretion of the biguanide measured. Irregularities in the plasma concentration curve were observed which appeared as systematic deviations from the ideal curve of a biexponential function. Because these deviations occurred only in the middle phase of the plasma concentration curve, it was nevertheless possible to calculate the pharmacokinetic parameters of butylbiguanide by use of a two-compartment open model. The principal pharmacokinetic parameters were determined according to this model after intravenous dosing and the following mean values were obtained:t 1/2 (β)=4.6 h (β=0.15 h−1),C P 0 =0.85µg/ml,V D =218 l,V T =157 l,V P =62 l,k 12=0.69 h−1,k 21=0.44 h−1,k el =0.54 h−1. Within 48 h after administration, an average of 72.4% of the intravenous and 74.4% of the oral dose had been excreted in the urine. Total clearance (Cl tot) averaged 536 ml/min and renal clearance (Cl ren) 393 ml/min. High concentrations of butylbiguanide were observed in the intestinal fluid (100–700 mg/ml) 20–40 min after oral administration. It was found that the drug accumulates in intestinal fluid, intestinal epithelium and liver tissue, and that it is secreted into the intestinal lumen. The concentrations of butylbiguanide in intestinal and liver tissue were 10–46 times higher than in plasma. The secretion of biguanide into the intestinal lumen may occur via the bile or the intestinal mucosa, but there is no evidence of significant biliary excretion of butylbiguanide.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 295-305 
    ISSN: 1432-1041
    Keywords: Mestranol ; ethynyloestradiol ; contraceptive compounds ; demethylation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The oestrogenic activity of mestranol depends on its demethylation to ethynyloestradiol. The reaction has been studied in man. The compound disappeared exponentially from plasma during the first 4 h after i.v. injection of [4-14C-] mestranol. The “metabolic clearance” for this phase amounted to 31.8 1/day per kg body weight. Methoxy-3H-labelled mestranol was prepared for the further studies, because if it is demethylated, the tritium would be transferred to HTO, which would equilibrate immediately with body water. The appearance in body water of tritium from [methoxy-3H-] mestranol could be described by two exponential functions, which corresponded to bi-phasic disappearance of the original compound from plasma. The rate constant of the first stage was: γ1=0.835 h−1, and of the second: γ2=0.034 h−1. HTO radioactivity was eliminated from the body by exchange of water. From the data obtained, a three-compartment model was constructed of the transfer of tritium from [methoxy-3H-] mestranolinto body water, which permitted computer simulation of the partial processes. The compartmental analysis suggested that mestranol differed from ethynyloestradiol mainly in the delayed and protracted manner in which hormonally active oestrogen entered the circulation. The proportion of [methoxy-3H-] mestranol demethylated to ethynyloestradiol (demethylation ratio) varied little, 53.7±5.0% (x±SD; n=6), and was consistent with clinical observations that mestranol is half as potent an oestrogen as ethynyloestradiol. Thus, the dose of mestranol required to produce a given effect has to be twice as large as that of ethynyloestradiol.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 375-380 
    ISSN: 1432-1041
    Keywords: Tranexamic acid ; pharmacokinetics ; man ; antifibrinolytic agents ; renal clearance ; two-compartment model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of tranexamic acid has been investigated in two healthy volunteers. The behaviour of the drug can be described in terms of a two compartment open model; the disposition (biological) half-life was 2.7 h and 1.9 h, respectively. In five normal volunteers the mean total recovery in urine 48 h after dosing was 94.8%. The renal clearance in the two subjects, adjusted to 1.73 m2 body surface area, was 135 and 132 ml/min/1.73 m2, respectively, indicating that tranexamic acid is eliminated by glomerular filtration and that neither tubular excretion nor absorption takes place.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 381-385 
    ISSN: 1432-1041
    Keywords: Phenazone ; pharmacokinetics ; plasma half-life ; gas chromatographic analysis ; intra-individual variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Intra-individual variability in the plasma half-life of phenazone has been studied in 16 healthy, young volunteers. Phenazone was analysed by a simple gas chromatographic method, which is specific in relation to known metabolites; 4′-methylphenazone was employed as the internal standard. Phenazone was given on two occasions, two or three months apart, in oral doses of 10 mg/kg. The plasma half-life determined from five time points was 10.9±1.5 h and 11.2±1.3 h respectively, on the two occasions. The mean intra-individual variability (0.86 h) was close to the methodological error of 4%.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 25-29 
    ISSN: 1432-1041
    Keywords: Pindolol ; uraemia ; pharmacokinetics ; β-blockade
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The elimination of pindolol in 25 patients with various degrees of renal failure has been studied after an intravenous dose of 3 mg. A linear correlation was not found between the elimination rate of pindolol and the endogenous creatinine clearance, and the half-life of the unchanged drug was independent of the severity of the renal failure. This implies greater metabolism of pindolol in anuric patients and the extrarenal elimination rate constantk mwas increased. Three patients with severe renal failure were given 3 mg14C-pindolol. They showed almost constant plasma levels of radio-activity for 6 h and then slow excretion with a half-life of 48 h, because of accumulation of metabolites in the blood. Up to 90% of the metabolites are glucuronides and sulphates which have no beta-blocking or other clinical activity. Thus, to produce beta-adrenergic blockade the same dose of indolol is required in healthy patients as in those with uraemia.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 59-60 
    ISSN: 1432-1041
    Keywords: Pizotifen ; isonicotinylhydrazine ; orexigen ; tuberculosis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Pizotifen (BC 105) has an orexigenic effect in patients with pulmonary tuberculosis. As these cases are often treated with isonicotinylhydrazine (INH), any effect of one of these drugs on the absorption of the other has been examined in a cross-over study in 8 healthy male volunteers. No difference was found between the absorption of INH given alone or together with pizotifen. It should be safe, therefore, to employ the combination of the orexigenic drug and INH in the treatment of tuberculosis as there will be no change in the concentration of therapeutic drug achieved.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 31-37 
    ISSN: 1432-1041
    Keywords: Diphenylhydantoin ; uraemia ; protein binding ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Diphenylhydantoin (2 mg/kg) was infused intravenously in four uraemic patients and four healthy volunteers and its plasma concentration measured during and after the infusion. The plasma concentrations were considerably lower in the uraemic subjects and the apparent volume of distribution was higher. These observations could be explained by the lower plasma protein binding of diphenylhydantoin in the uraemics. The overall elimination rate constant β was greater (shorter half-life) in the uraemic patients. This difference could not be explained by reduced plasma protein binding, but it might be due to induction of diphenylhydantoin metabolism in the uraemic state. it is concluded that monitoring of the plasma levels of drugs in uraemic patients should be combined with determination of the extent to which the compounds are bound to plasma proteins.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 51-58 
    ISSN: 1432-1041
    Keywords: Rifampicin ; plasma level ; pleural fluid concentration ; microbiological assay ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Single oral doses of rifampicin (RMP) were given to 31 patients with pleural effusions of various aetiologies. The concentrations of RMP and its active metabolites in pleural fluid and plasma were determined by an agar diffusion method using paper discs as diffusion centres. The plasma concentrations reached a peak within 3 h and then declined monoexponentially; in pleural fluid, RMP concentration rose slowly to reach a plateau that lasted for several hours. There were marked differences between subjects in the observed concentrations of RMP. During the first 12 h the plasma levels exceeded those in pleural fluid, but after 24 h the concentration of RMP in pleural fluid was higher than in plasma. If multiple oral doses of RMP 10 mg/kg b. w. are given every 24 h, as is common in the treatment of tuberculosis, therapeutic concentrations may be expected in pleural fluid for the major part of each day.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 17-24 
    ISSN: 1432-1041
    Keywords: Pindolol ; beta-blockade ; pharmacokinetics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of absorption, distribution and excretion of pindolol have been investigated in 17 volunteers after an oral dose or intravenous infusion of 5 mg. The calculated absorption was 92%. The time course of the plasma levels appeared to follow first order kinetics with an apparent half life of 3.6 (oral) and 3.1 (i.v.) hours. The cumulative urinary excretion att=∞ was 36.1% and 39.2% of the dose administered, respectively, indicating extensive metabolism of the drug. The distribution volume was 136 l. Peak plasma levels were found 80 min after oral administration and they showed up to 4-fold variation after identical doses. Renal clearance was 216 ml×min−1 and total clearance was 483 ml×min−1. In plasma 57% of pindolol was bound to protein.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 119-124 
    ISSN: 1432-1041
    Keywords: Anticonvulsants ; phenytoin ; diphenylhydantoin ; bioavailability ; generic inequivalence ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma levels of phenytoin (diphenylhydantoin, DPH) in epileptic patients were significantly higher after treatment with either of two preparations containing the sodium salt of DPH, than after treatment with the same dose of the free acid. This was confirmed in both short and long term studies, and in the latter increased plasma levels of DPH were accompanied by better control of generalized seizures. The degree of acute side-effects in 6 out of 10 patients whose treatment was changed from DPH-acid to DPH-sodium was proportional to the plasma level of DPH; the latter varied from 22.8 to 34.9 µg/ml in affected patients. After a single oral dose in healthy volunteers, the sodium salt of DPH showed much better bioavailability than the free acid. The differences in bioavailability in patients and volunteers probably depended on differences in particle size in the preparations of the sodium salt of DPH and its free acid. The excipient, lactose or starch, did not seem to affect the bioavailability of the two formulations of sodium-DPH.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 217-225 
    ISSN: 1432-1041
    Keywords: Rifampicin ; p-aminosalicylic acid ; drug interaction ; isoniazid ; pharmacokinetics ; antituberculous therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Single oral doses of rifampicin (10 mg/kg body weight), p-aminosalicylic acid (0.2 g/kg), isoniazid (10 mg/kg), or rifampicin and either p-aminosalicylic acid or isoniazid, were given to 69 tuberculous patients with normal renal and hepatic function. Ten-fold interindividual differences were observed in the peak serum concentrations and half-lives of rifampicin; its half-life was reduced from 4.3 h after the first dose to 3.1 h after the third dose, possibly due to self-induction of its own metabolism. No effect on its serum concentration or half-life, nor on those of isoniazid, were found after simultaneous oral administration of the two drugs. After treatment with rifampicin and p-aminosalicylic acid, the peak serum level of the former was delayed from 2 to 4 h, it was reduced from 8.0 to 3.8 µg/ml, and the mean area under the serum concentration curve throughout the entire 8 h study period was also lowered by about half. Individual patients did not attain therapeutically effective peak serum concentrations of rifampicin if also treated withp-aminosalicylic acid. The interaction observed between the two drugs is probably due to impaired gastrointestinal absorption of rifampicin, either by alteration of its physico-chemical properties or by a decrease in the gastric emptying rate combined with more rapid intestinal transit. The combination of these two drugs is unsuitable for the routine chemotherapy of tuberculosis.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 7 (1974), S. 249-252 
    ISSN: 1432-1041
    Keywords: Practolol ; renal failure ; uraemia ; beta-blockade ; pharmacokinetics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of renal failure on the excretion of oral doses of practolol has been studied. The plasma half-life increased up to 6.6 times normal and the cumulative urinary excretion of the drug was reduced. There was a linear correlation between the overall elimination rate constant of practolol and inulin and creatinine clearances. A linear correlation was also found between the renal clearances of practolol and inulin. The dose of practolol required for maintenance therapy should be reduced in patients with impaired renal function.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 2 (1974), S. 123-148 
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; computer program ; NONLIN ; data weighting ; isoniazid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Several important statistical aspects of pharmacokinetic analyses by digital computer are discussed. These include selection of appropriate equations, weighting of data, precision of parameter estimates, comparisons of parameters, analysis of weighted residuals, and criteria useful in the selection of particular models. Data obtained after administration of isoniazid and isonicotinuric acid to man are analyzed to illustrate the usefulness of the discussed methods.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 2 (1974), S. 495-509 
    ISSN: 1573-8744
    Keywords: hepatobiliary transport ; rat ; bromphenol blue ; pharmacokinetics ; roles of liver cytoplasmic Y- and Z-binding proteins and T binder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new pharmacokinetic model is proposed to explain the hepatobiliary transport of a nonmetabolized sulfonic acid dye, bromphenol blue, which is actively transported from the bloodstream into bile. This model has the advantage of taking into account the roles of the liver cytoplasmic Y- and Z- binding proteins and T binder.
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  • 16
    ISSN: 1573-8744
    Keywords: digoxin ; pharmacokinetics ; two-compartment model ; three-compartment model ; radioimmunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An experiment has been carried out in man designed to compare the fit of a two- and a three-compartment pharmacokinetic model to experimentally determined serum digoxin concentration-time data following rapid intravenous injection of 1.0 mg of the drug. Digoxin was administered to five healthy male volunteers, blood samples were withdrawn repetitively over a period of 72 hr, and samples were assayed using a 125 I radioimmunoassay. Appropriate equations describing two- and three-compartment open models were fitted to the experimental data using weighted nonlinear least squares regression analysis. It was demonstrated that the three-compartment fit resulted in a statistically significant reduction in residual error, a marked improvement in the randomness of scatter of the experimental data about the serum digoxin-time curve, and better agreement of the predicted serum concentration-time curve with experimental serum digoxin concentrations. Thus the three-compartment open model is the simplest pharmacokinetic model consistent with the data observed in this experiment.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 2 (1974), S. 347-364 
    ISSN: 1573-8744
    Keywords: metoprolol ; β-receptor antagonist ; pharmacokinetics ; disposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of 3H-metoprolol, a new selective β 1-receptor antagonist, have been studied in healthy volunteers by following the plasma concentrations and the urinary excretion of the unchanged compound and its total radioactive metabolites after oral and intravenous administration. The compound was rapidly and completely absorbed after oral administration, and about 40% of the dose reached the systemic circulation. The estimated half-life of the absorption process was 10 min. Metoprolol was extensively distributed to extravascular tissues, with the half-life of the distribution phase close to 12 min. About 95% of the dose was excreted in the urine within 72 hr, mainly in metabolized form. The elimination halflife of the compound was close to 3 hr as was also the half-life of the total metabolites after oral administration. After intravenous administration, the elimination half-life of the metabolites was raised to 5 hr, indicating that the route of administra tion might influence the metabolic pathways of the parent compound.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 119-134 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: L-Asparaginase has been attached by chemical means to the inner surface of nylon tubing. An experimental study has been carried out of the flow kinetics for such a system, asparagine solutions at various concentrations being passed through two lengths of tubing at various flow rates. Measurements were made of the concentration of the product ammonia at the tube exit, and of the rate of formation of ammonia, under the various conditions. Apparent Michaelis constants, Km(app), were some three orders of magnitude higher than the Km for the enzyme in free solution (∼13 × 10-6JM). The results were analyzed with respect to the theoretical treatment described in the preceding paper (Kobayashi and Laidler), three different methods being employed. It is concluded that at lower substrate concentrations and flow rates the reactions are largely diffusion-controlled, the enhanced Km(app) values being largely if not entirely due to the diffusion control; ionic strength studies showed electrostatic repulsion effects to be unimportant. At high concentrations and high flow rates (when the diffusion layer is of negligible thickness) the diffusional effects are minimized, and Km(app) approaches the true Km value for the immobilized enzyme.
    Additional Material: 3 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 789-805 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It has been demonstrated that ozone dosages of 0.06 lb and 0.78 lb per pound of lignin can reduce the optical density (in the visible range) of the latter by 82% and 92%, respectively. The reduction in color is accompanied by a shift in the molecular weight distribution of lignin from a broad peak of between 20,000 and 70,000 to lower molecular weight, species including substantial amounts possessing a molecular weight of 1000 or less. The cost of decolorizing a typical kraft paper bleach effluent is estimated to be under 50¢/1000 gal which compares favorably with competitive decolorizing processes. Lignin ozonation results in the production of a series of decolorized products which can serve as the sole source of carbon for a variety of microorganisms. Feasibility studies indicated that at least 40% of the ozonated material can be transferred into microbial biomass (protein) as well as other products of commercial interest such as fumaric acid and penicillin.
    Additional Material: 7 Ill.
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  • 21
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 859-862 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 545-550 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 23
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 24
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new and simple method for immobilization of enzymes by the aerobic radio-polymerization of acrylamide was developed. Irradiation treatment of acrylamide in the frozen state produces a spongy immobilized enzyme membrane without the addition of carriers. Aerobic polymerization yields of acrylamide in the frozen state were increased by the addition of starch and also by lyophilization.Glucose oxidase (activity recovery was 12.3-33.7%), invertase (69.2%), D-amono acid oxidase (25.0-70.5%), aminoacylase (39.2-43.7%), mold α-amylase (18.0%), malt β-amylase (4.1%), glucoamylase (6.5%), alkaline protease (5.3%), and neutral protease (10.5%) were immobilized by this method. Invertase entrapped by this method had a wider optium pH range and was active at higher temperatures.
    Additional Material: 5 Ill.
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  • 25
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 26
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 757-770 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mixing of the anaerobic digester contents significantly influences the efficiency of this operation; in particular, hydraulic dead zones are extremely detrimental to the reaction kinetics involved in anaerobic digestion. An analysis of the relative importance of thermal fluid movement in the digester to those caused by fluid inflow and outflow is presented. As an example, these principles are applied to a digester at the South Bend Wastewater Treatment Plant. Experimental measurements, which have general applicability for the measurement of digester mixing volume, confirm the theoretical conjectures. Various types of optimizations can be attempted on this mixing operation. One such optimization applied to gas lift mixers, as employed in the South Bend Treatment Plant, is illustrated.
    Additional Material: 6 Ill.
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  • 27
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 807-826 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Activated sludge is a widely used aerobic biological waste-water treatment process. A rational approach to least cost design of an integrated system is described which includes the following processes: activated sludge reactor, final settling tanks, gravity thickening, and aerobic sludge digestion. Both capital and operation and maintenance costs are considered. Biological reactor design is based on microbial kinetic concepts and continuous culture of microorganisms theory. Biological solids retention time (θc) is utilized as the primary independent design variable to which system performance is related, e.g., effluent quality, ammonia oxidation, and excess sludge production. Liquid-biomass separation is based on the batch flux technique, a rational approach to design of gravity separators (final settling tanks). Trade-offs among reactor volume, clarifier size, recycle pumping capacity, thickener capacity, digester volume, air requirements, and sludge production are discussed. The optimum design is taken as the combination of these parameters within the acceptable design domain, determined by effluent quality criteria, that results in minimum cost. While the method described is general, design of a given treatment system depends on availability, from lab or pilot studies, of system specific numerical values for biological growth coefficients and biomass setting characteristics. A design example illustrates the approach.
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  • 28
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    Biotechnology and Bioengineering 16 (1974), S. 863-865 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 29
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    Biotechnology and Bioengineering 16 (1974), S. 897-908 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The immobilization of glucose oxidase and catalase by adsorption within the pores of controlled-pore titania has yielded a remarkably stable enzyme system. Catalase apparently acts as both a stabilizer and an activator for glucose oxidase within the pores of this material. Hydrogen peroxide concentrations and flow rates have a marked effect upon the apparent activity of the immobilized enzyme system. The carrier parameters were varied to obtain optimum loading and stability information.
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  • 30
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    Biotechnology and Bioengineering 16 (1974), S. 943-963 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-galactosidase from E. coli (β-D-galactose galactohydrolase, EC 3.2.1.23) has been entrapped in a crosslinked 2-hydroxyethyl methacrylate gel with a 35% retention of activity. The kinetic behavior of the gel-entrapped enzyme has been studied in a recirculation reactor system, the substrate being o-nitrophenyl-βhyphen;D- galactopyranoside. Kinetic constants were determined for particle sizes ranging from 69 to 231 μm in diameter and compared to those of the free enzyme. External diffusion effects were eliminated by operating at high recirculation flow rates. A fourfold increase in Km(app) was observed for the 231 μm particles, consistent with existing theoretical treatments for internal diffusion effects.An Arrhenius plot of rate data showed significant curvature at higher temperatures, which was attributed to the effects of internal diffusion. The pH-activity profile of the gel-entrapped enzyme was bell-shaped at high substrate concentration and, in contrast to the free enzyme, could be fitted to the titration curve of two ionizable groups, a basic group having a pK of 8.6. The gel-entrapped enzyme had a higher pH optimum and retained a larger percentage of its maximal activity at alkaline pH than the free enzyme; its pH stability at high pH was also much better.The thermal stability of the gel-entrapped enzyme was studied and found to be 14 days at 22°C and 65 min at 45°C.
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  • 31
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The consideration of fermentation principles in the treatment of industrial and sanitary waste waters leads to substantial process improvements. In particular, the rate of reaction can be improved by several fold by establishing the proper environmental conditions for microbial growth in a fermentation system. Recent work on the concentric cylinder air lift has shown it to be an economical fermentor with many advantages over conventional fermentors. An attempt to improve the economical performance of this system led to the development of the thin channel rectangular air lift fermentor. This was based upon a theoretical analysis of performance parameters. The analysis indicates decreased bubble coalescence, increased bubble entrainment, decreased power costs, increased mass transfer coefficients, and decrease capital costs. Experience using a prototype thin channel rectangular air lift system with sanitary and industrial waste-water treatment systems has demonstrated exceptionally high rates of BOD removal at low operating and capital costs.
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  • 32
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    Biotechnology and Bioengineering 16 (1974), S. 1213-1225 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When the effect of catabolite repression is eliminated Saccharomyces cerevisiae prefers an aerobic metabolism. The potential for completely aerobic catabolism exists even in circumstances where its action is limited by the oxygen available. When the oxygen absorption in the medium is adequate, yeast uses a solely oxidative metabolism for energy-yielding reactions. The changes observed in the activity of malate dehydrogenase can be described as a function of two isoenzymes, both of which are affected by oxygen; the isoenzyme participating in the glyoxylate cycle shows variations in activity similar to that observed in isocitrate lyase. NAD-linked glutamate dehydrogenase activity roughly follows that of malate dehydrogenase and isocitrate lyase; in cultivations with the same growth rate the NADP-linked dehydrogenase is insensitive to the oxygen level. The cytochromes aa3, b, and c have a clear maximum at low oxygen tension, the most sensitive being cytochrome aa3. The imbalance between cytochrome c:oxygen oxidoreductase activity and the amount of cytochrome aa3, and the correlation observed between respiration rate and the activities of cytochrome c oxidase and NADH2:cytochroine c oxidoreductase are discussed. Methods used for estimation of cytochromes are compared.
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  • 33
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    Biotechnology and Bioengineering 16 (1974), S. 21-39 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An apparatus is described which is designed for preparative freeze concentration experiments by the technique of normal freezing. It has a capacity of approximately 22 liters distributed over twelve vessels. The influence of various geometrical and chemical parameters such as stirring speed, crystallization rate, and sample composition on the normal freezing of protein solutions are discussed. For dilute protein solutions (〈0.1%) the concentration factor generally was 8- to 10-fold with recoveries of 90-100 percent. With higher protein concentrations and at ionic strengths higher than approximately 0.05, the recovery was decreased. No loss of activity was detected when concentrating enzyme solutions.
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  • 34
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    Biotechnology and Bioengineering 16 (1974), S. 149-156 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: HeLa S3 cells in suspension culture are resynchronized in each successive generation by exposure to 0.25mM thymidine. The resynchronization approach appears to be superior to single- and double-block techniques because the period of effective inhibition of DNA synthesis is significantly shortened. Gram quantities of highly synchronous viable cells have been produced on a daily basis.
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  • 35
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In an effort, to develop comprehensive mathematical models for use in optimizing fermentation processes, product rate data taken at constant pH's for the lactic acid fermentation (Lactobacillus delbrueckii) were analyzed. It was observed that the rate of acid synthesis-time trajectories exhibited a “shoulder” effect at pH's less than 5. That is, a nearly constant rate of synthesis for up to 10 hr in the late growth phase, out of a maximum total fermentation time of 70 hr. This effect was used as a clue from which to structure the proposed model with parallel pathways. Simulating shunting pathways does, in fact, demonstrate that, the notion of parallelism is consistent with the expression of a shoulder. It is postulated, therefore, that a differential pH effect between two parallel pathways can account for the presence of a shoulder when both routes prevail, and no shoulder when either pathway predominates.
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  • 36
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    Biotechnology and Bioengineering 16 (1974), S. 555-557 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 37
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    Biotechnology and Bioengineering 16 (1974), S. 925-931 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NAD was covalently linked to Sepharose-4B using a 6 carbon spacer. Sterile, dialyzed spent culture medium containing 100 Lf/ml of diphtheria toxin or material concentrated by (NH4)2SO4 precipitation containing 1500 Lf/ml, was chromatographed on a column of NAD-Sepharose. Ultraviolet absorbing material which did not flocculate with diphtheria antitoxin was eluted with 0.02M phosphate buffer. When the elation buffer was changed to one containing 0.5M NaCl, purified toxin was eluted off the column.
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  • 38
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    Biotechnology and Bioengineering 16 (1974), S. 965-985 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The yeast Candida tropicalis utilizes both glucose and hydrocarbons as sole carbon sources. When grown on hydrocarbons, the cells contain twice as much lipid as when grown on glucose. In transient continuous culture experiments, following a substrate change from glucose to hexadecane, an adaption phase occurred. During this phase the lipid concentration per cell increased greatly. It is proposed that a high cellular lipid concentration is necessary for hydrocarbon assimilation, and this is not just a reflection of the lipophilic nature of the substrate.
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  • 39
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    Biotechnology and Bioengineering 16 (1974), S. 1005-1013 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Information is presented concerning revisions of the fermentation air system equipment which improved the sterility situation in the production of monosodium glutamate.Basically, the revision were a relocation and elevation of the intake to the air compressors and installation of a retention chamber after the compressors to take advantage of the heat of compression.The extended high temperature retention ensures sterile air to the final air filter before the fermentor. Contamination losses - mainly from phage - have been materially reduced relative to the level prevailing before the change.
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  • 40
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    Biotechnology and Bioengineering 16 (1974), S. 1069-1079 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method is described for the large-scale preparation of erythropoietin from anemic sheep plasma. DEAE-cellulose and carboxymethylcellulose column chromatography was used to prepare Step II erythropoietin. A total of 168 sheep yielded 499 liters of plasma from which 323,000 IU of Step II erythropoietin was obtained.
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  • 41
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    Biotechnology and Bioengineering 16 (1974), S. 1103-1112 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Galactosidase has been purified from an ammonium sulfate precipitate of E. coli strain ML308 by biospecific adsorption on a column of agarose gel substituted with p-aminophenyl-β-D-thiogalactopyranoside. The system described using a 1.8 liter column has a useful processing capacity of 3.8 × 106 units of β-galactosidase per 2 hr cycle. This corresponds to about 5 g of pure enzyme. An electromechanical timing device operates a set of six solenoid valves and carries out a preset program consisting of sample application, washing, and elation operations.
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  • 42
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    Biotechnology and Bioengineering 16 (1974), S. 1113-1122 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Porous hollow cellulose fibers have been used to separate a nonflowing enzyme solution of alkaline phosphatase from a continuous flow of substrate. The porosity of the hollow fiber membrane allows the substrate and product to diffuse freely through the membrane while restricting the permeation of the enzyme. The resulting “immobilized” enzyme system has been shown to behave as a continuous reactor - converting p-nitrophenylphosphate to p-nitrophenol. By varying the concentrations, flow rate, etc., either diffusion or enzyme kinetics can be studied. The continual influx of product and removal of substrate at steady state allows the study of kinetics of relatively short half-life enzymes and unstable systems.
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  • 43
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    Biotechnology and Bioengineering 16 (1974), S. 1517-1528 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized glucoamylase, invertase, and β-galactosidase were prepared by using N-vinylpyrrolidone monomer (VP) under γ-ray irradiation. The enzyme-VP solutions were gelled by irradiation with 2.9 Mrad and the added enzymes were almost completely entrapped. Activity losses on entrapping were 55% for the VP-glucoamylase gel, and more than 90% in the case of VP-invertase and VP-β-galactosidase gels. No leakage of enzyme from these gels could be detected within 1 hr. The VP-glucoamylase gel was capable of hydrolyzing dextrin (mol wt 10,400) to glucose and the glucose equivalent was equal to that obtain able with native enzyme. The optimum temperature, heat stability, pH activity curve, and pH stability of VP-glucoamylase gel were slightly inferior to those of native enzyme, while Km was a little larger than that of native enzyme.
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  • 44
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    Biotechnology and Bioengineering 16 (1974), S. i 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 45
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    Biotechnology and Bioengineering 16 (1974), S. 61-76 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polysaccharide was synthesized by Aureobasidium pullulans (or Pullularia pullulans) 2552 in a sucrose medium. The field apparent viscosity of the culture medium from shake flask experiments rose to 24,500 cP and then dropped toward its initial value as the fermentation progressed. The magnitude of the maximum apparent viscosity depended on the initial pH of the fermentation broth. The inoculum age influenced the cultivation period before which the maximum viscosity was reached. Rheograms of the fermentation broths showed a change in viscosity behavior from Newtonian to pseudoplastic, and then toward Newtonian characteristics during the fermentation. The calculated non-Newtonian index was found to be a sensitive factor for the indication of the non-Newtonian behavior. Such behavior could not be detected from rheograms. Viscosity profiles of polysaccharide isolated from various stages of the fermentation showed a change from Newtonian to pseudoplastic behavior depending on the concentration (0-2%) of polysaccharide.
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  • 46
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    Biotechnology and Bioengineering 16 (1974), S. 181-208 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental investigation on the rheology of penicillin broths was undertaken in order to obtain more understanding of this important aspect of the fermentation process. The measuring technique consisted in observation of the torque exerted upon a rotating turbine impeller. The experimental data were interpreted in terms of a model which basically is a synthesis of a known relationship for the rheological behavior of printing ink (Casson equation) and some considerations analogous to the rheological description of polymer solutions (excluded volume concept). One of the key variables in the model is a morphology factor, which can be used for a quantitative description of mycelial morphology. The value of the morphology factor can be determined experimentally by a simple viscosity measurement in combination with a mycelial dry weight determination. There are strong indications that the model may be applicable to mycelial broths other than those of penicillin.
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  • 47
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    Biotechnology and Bioengineering 16 (1974), S. 169-179 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The utility of an immobilized enzyme depends not only on initial loading but also on operational half-life. The loss of activity of an immobilized enzyme in a column reactor may occur in several ways. It is therefore of interest to determine whether the decay in activity is due to the rupture of any of the enzyme-carrier bonds in the composite. In order to do this, it is first necessary to establish whether the enzyme on the composite is in fact covalently bound or adsorbed. In this report we have shown that there are a number of covalent links per protein molecule. We have also shown that the bond energies are sufficient to prevent shearing of the enzyme itself from the composite under any stresses which may occur in a chromatography column or packed-bed reactor during continuous operation. The effect of the siloxane linkage on composite stability is also discussed.
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  • 48
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    Biotechnology and Bioengineering 16 (1974), S. 475-484 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fiber-optic retroreflective turbidimeter has been developed to automatically and continuously assay the cell concentration in a fermentor by measuring the turbidity of the solution as a function of the light scattered at 180° to the incident light. The output signal is nearly directly proportional to the cell concentration in a fermentor when the sample stream contains from 0 to more than 50 g of cells per liter (wet weight). The device consists of a bifurcated fiber-optics light pipe with its distal end inserted into a flow cell through which the material to be analyzed passes. A light source on one proximal branch of the light pipe illuminates the sample stream; light that is back-scattered from participates in the stream re-enters the light pipe and is returned to a photodetector on the other proximal branch of the light pipe. A signal conditioning system connected to the optical head by a cable provides gain and zero adjustment.
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  • 49
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    Biotechnology and Bioengineering 16 (1974), S. 513-523 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Purified enzymes encapsulated in liquid surfactant membranes have been shown to retain their catalytic activity. In general, previous work on encapsulation has been confined to single enzymes. The system has now been extended to encapsulate a bacterial cell-free homogenate. Liquid membrane-encapsulated bacterial cell-free homogenate reduces effectively NO3- to NO2- and other nitrogen compounds of lower oxidation state. This technique of removing nitrates and nitrites may have application in waste-water treatment. Also, it has been shown that encapsulated cell-free homogenate does not leak and there is no absorption of the substrate onto the liquid surfactant membrane surfaces. The reduction in the reaction rates is discussed in terms of solubility of the substrate and the rate of permeation of the substrates through the liquid surfactant membrane.
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  • 50
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    Biotechnology and Bioengineering 16 (1974), S. 531-538 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 51
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    Biotechnology and Bioengineering 16 (1974), S. 551-553 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 52
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Amylase (EC 3.2.1.2) and pullulanase (EC 3.2.1.9) have been covalently bound in a two-enzyme system to a crosslinked copolymer of acrylarmide-acrylic acid by using a water-soluble carbodiimide. The coupling yields based on the amounts of added β-amylase and pullulanase were 40% and 38%, respectively, with residual enzymic activities of 22% and 32% of those of free enzymes. A markedly increased operational stability was observed for the immobilized two-enzyme system compared to the free enzymes in solution. In order to find optimal operational conditions the influence of different pH values and temperatures on the conversion process was investigated. The action of the immobilized β-amylase-pullulanase derivative on partially hydrolyzed starch (DE 3.4-10.7) in a packed bed column was studied. Analysis of the product was performed using gas-liquid chromatography.
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  • 53
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    Biotechnology and Bioengineering 16 (1974), S. 635-657 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Candida tropicalis was cultured in a chemostat-type fermentor with n-hexadecane, dispersed in water as submicron droplets, as the only carbon substrate. The emulsion as well as the aqueous medium were fed continuously into the fermentor. A Monod-type equation can correlate the specific group rate in the continuous fermentor with the concentration of submicron droplets. The same equation can also be fitted to the data for the conventional-type batch culture in the same fermentor in which an oil phase as well as an aqueous phase existed, if the hydrocarbon concentration in the aqueous phase excluding oil drops is employed as the substrate concentration. This demonstrates that Candida tropicalis takes up only submicron droplets of n-hexadecane as the carbon substrate.
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  • 54
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    Biotechnology and Bioengineering 16 (1974), S. 689-696 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A soluble fungal lactase (lactase-W) of greater activity that the previously available fungal lactase (lactase-M) has been covalently coupled to ZrO2-coated porous glass particles and 1 mm diameter porous TiO2 particles. The immobilized lactase-W appears to give results similar to the lactase-M except for the operational half-life. At 30°C the half-life of the lactase-M appears to exceed that of the lactase-W by approximately 100 days under operational conditions.
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  • 55
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    Biotechnology and Bioengineering 16 (1974), S. 739-755 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Humic substances were isolated during batch aeration studies with activated sludge and a complex waste source, by using concentration and separation techniques that employ reverse osmosis, ultrafitration, and gel permeation chromatography. The study suggests that the formation of high molecular weight humic substances may occur after the removal of the readily available carbon source. The amount of refractory material finally present in the solution will depend on its adsorptive properties toward bacterial cells. The adsorptive characteristics may be determined by the magnitude of the carbohydrate fraction present in the humic substances. If the carbohydrate content decreases, adsorption onto the cells may decrease resulting in an impairment of both the floe formation and settleability of the sludge floes. Decreased adsorption will result in a higher total organic carbon content and an increase in color bearing materials in the effluent.
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  • 56
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    Biotechnology and Bioengineering 16 (1974), S. 723-738 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Previous experimentation in our laboratory has shown that the classical theory developed for continuous growth of pure cultures in completely mixed aerobic systems in which the recycle cell concentration factor, c (where c = XR/X), is a selectable system constant, did not provide a suitable model for the heterogeneous (natural) populations of the activated sludge process. Another model was derived in which the recycle cell concentration, XR was employed as a system constant instead of c, and computational analysis was performed. Laboratory pilot plant experimentation was undertaken in order to determine whether a “steady state” in aerator biological solids concentration, X̄, and substrate concentration, S̄, could be approached under this mode of operation. Studies were performed at various organic feed concentrations holding dilution rate, D, at 0.125 hr-1, hydraulic recycle ratio, α, at 0.25, and XR at 10,000 mg/liter. Also, values of maximum specific growth rate, μmax, and saturation constant, Ks were determined. It was found that the model approached the steady state condition with heterogeneous populations more closely than did the classical model, and the high degree of treatment efficiency predicted by the model was demonstrated experimentally.
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  • 57
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 58
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    Biotechnology and Bioengineering 16 (1974), S. 909-923 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The intrusion of diffusion in heterogeneous enzyme reactions, which follow. Michaelis-Menten kinetics, is quantitatively characterized by dimensionless parameters that are independent of the substrate concentration. The effects of these parameters on the overall rate of reaction is illustrated on plots commonly employed in enzyme kinetics. The departure from Michaelis-Menten kinetics due to diffusion limitations can be best assessed by using Hofstee plots which are also suitable to distinguish between internal and external transport effects. A graphical method is described for the evaluation of the reaction rate as a function of the surface concentration of the substrate from measured data.
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  • 59
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    Biotechnology and Bioengineering 16 (1974), S. 987-990 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 60
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    Biotechnology and Bioengineering 16 (1974), S. 1004-1004 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 61
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    Biotechnology and Bioengineering 16 (1974), S. 1045-1053 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies exploring the effect of two nonaqueous solvents on enzyme activity were done using chloroperoxidase as a model system. Chloroperoxidase produced by Caldariomyces fumago is a bifunctional enzyme with halogenating activity at pH 3 and peroxidation activity at pH 5 to 6. Methanol affected both of these activities similarly. Furthermore, methanol and the halogen acceptor, monochlorodimedon, competitively inhibit the reaction. These results are discussed in terms of the site of action of methanol. At 10% methanol concentration, the enzyme retained up to 33% of its activity depending on the monochlorodimedon concentration. Dimethylsulfoxide at 10% concentration permitted up to 47% retention of activity. Its effects on the enzyme are more complex than methanol and are discussed in terms of a transitory inactivation of the enzyme.
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  • 62
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    Biotechnology and Bioengineering 16 (1974), S. 1095-1102 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzyme tannase has been immobilized on an inorganic support by covalent attachment. This immobilized enzyme was characterized and half-lives determined. Since this enzyme has application in the treatment of tea cream, experiments were also carried out to determine the effect of tea on enzyme half-life.
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  • 63
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    Biotechnology and Bioengineering 16 (1974), S. 1135-1137 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 64
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 65
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 66
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    Biotechnology and Bioengineering 16 (1974), S. 1299-1320 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overall rate of reaction of buffered gel-immobilized glucose oxidase particles is described by means of an enzyme rate equation which relates the overall reaction rate of a particle to the free solution characteristics of the enzyme, the effective diffusivity of the limiting substrate in the gel, the characteristic particle size, and the limiting substrate concentration adjacent to the gel surface. This equation accounts quantitatively for the limitation of the overall rate of reaction by substrate diffusion, and it is used to illustrate the influence of the system parameters, i. e., particle size, enzyme concentration, and pH, on the extent of the diffusional resistance associated with gel-immobilized glucose oxidase particles.The enzyme rate equation is generally applicable to those enzymes whose kinetics approximately follow Michaelis-Menten form when in free solution.
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  • 67
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    Biotechnology and Bioengineering 16 (1974), S. 1373-1392 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The response of two-species commensalistic systems in a chemostat has been investigated after perturbations in steady state conditions and after step changes in dilution rate. The system is inherently stable with not more than three overshoots and undershoots possible. More complicated commensalistic systems are less stable, with limit cycle response occurring after dilution rate changes when feedback inhibition and feedforward activation occurs. In general variation of feedback parameters is more effective in changing the behavior of the systems than variation of feedforward parameters. Limited agreement with the experimental data of Chao and Reilly was obtained.
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  • 68
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    Biotechnology and Bioengineering 16 (1974), S. 1407-1411 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 69
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    Biotechnology and Bioengineering 16 (1974), S. 1425-1429 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 70
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    Biotechnology and Bioengineering 16 (1974), S. 1471-1493 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Waste cellulose was a suitable carbon source for cellulose production by Trichoderma viride. The enzyme can be produced in submerged fermentation using newspaper as a growth substrate. A variety of pure and complex cellulosic materials were hydrolyzed by culture filtrates. Saccharification of 5% slurries after 48 hr ranged from 2-92%. The rate and extent of hydrolysis was controlled by degree of crystallinity, particle size, and presence of impurities. Newspaper was used to evaluate methods for the pretreatment of substrate. The best pretreatment was ball milling which gave good size reduction, maximum bulk density, and maximum susceptibility. Hammer milling, fluid energy milling, colloid milling, or alkali treatments were less satisfactory. Dissolving cellulose in cuprammonium, or carbon disulfide (Viscose) and then reprecipitating gave a susceptible, but low bulk density product. However the susceptibility was lost if the substrate was dried. Because of costs, low bulk density, necessity of keep ing the substrate wet, and generation of chemical waste streams dissolving cellulose to increase reactivity does not seem a practical approach.Cellulose fractions separated from municipal trash or agricultural residues such as milled fibres from bovine manure are promising substrates for conversion.
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  • 71
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    Biotechnology and Bioengineering 16 (1974), S. 1537-1544 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aminoacylase was covalently coupled to several porous ceramic type carriers and studied for durability under operating conditions. These studies indicate that it should be possible to develop a commercially economic system based on ceramic carriers for the resolution of racemic mixtures of amino acids.
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  • 72
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    Biotechnology and Bioengineering 16 (1974), S. 1553-1556 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 73
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    Biotechnology and Bioengineering 16 (1974), S. 1567-1587 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetic studies on the parameters influencing the potential industrial application of an immobilized two-enzyme system of β-amylase and pullulanase for conversion of starch to a product with high maltose content, have been performed. The apparent Michaelis constant, the apparent product inhibitor constant, and the activation energy have been determined for the immobilized preparation and compared to the values for the corresponding soluble enzyme system. The catalytic activity of the immobilized enzymes was studied in a plug-flow reactor and a continuous feed stirred tank reactor. Mathematical models for these reactors have been formulated and adapted to fit the experimental data. Comparisons of the reactor efficiencies were made and the conditions were found to be such as to favor the plug-flow reactor. Results on operational stability tests at different temperatures and substrate concentrations are given.
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  • 74
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The microbial cells of Pseudomonas putida ATCC 4359 were immobilized by entrapment in a polyacrylamide gel lattice. Enzymatic properties of L-arginine deiminase of the immobilized P. putida cells were investigated and compared with those of the intact cells. The permeability of substrate or product through the cell wall und the heat stability of the enzyme were increased by immobilization of the cells. No difference was observed between pH activity curves of the intact and immobilized cells. The optimal temperature for the formation of L-citrulline was 37°C for the intact cells and 55° C for the immobilized cells.When an aqueous solution of 0.5M L-arginine hydrochloride (pH 6.0) was passed through a column packed with the immobilized cells at a flow rate of SV = 0.26 at 37°C, L-arginine was completely converted to L-citrulline. The enzyme activity of the column was stable and the continuous production of L-citrulline could be carried out at 37°C for the month by using the immobilized cell column. From the effluent of the column, L-citrulline was easily obtained in a good yield.
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  • 75
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Nitrifying characteristics were compared for an extended aeration (total cell recycle) process and one employing an engineering modification of the process utilizing a “hydrolytic assist” to aid biological autodigestion. Laboratory pilot plants were run over a period of years, and it was found that the recently recommended “hydrolytic assist” did not militate against production of a highly nitrified effluent. Under this mode of operation, the effluent was as nitrified as the effluent from the normal extended aeration process. It was also found that the modified process rapidly recovered its nitrifying capability after a period of deprivation of excess ammonia nitrogen. Throughout the period of operation, substrate removal efficiency remained high.
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  • 76
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    Biotechnology and Bioengineering 16 (1974), S. 99-118 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical treatment is given of the kinetics of reactions catalyzed by enzymes attached to the inner surface of a tube, through which the substrate solution passes. A utilization factor, the ratio of the actual reaction rate to that in the absence of diffusional effects, is defined. A numerical procedure is proposed and numerical and approximate solutions for the utilization factor are given for five kinetic conditions: (a) Michaelis-Menten behavior, (b) substrate inhibition, (c) product inhibition (competitive), (d) product, inhibition (non-competitive), and (e) product inhibition (anticompetitive). When the enzyme chemically attached to a tube obeys a Michaelis-Menten relationship, criteria for insignificant and significant diffusional effects are proposed.
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  • 77
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    Biotechnology and Bioengineering 16 (1974) 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 78
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    Biotechnology and Bioengineering 16 (1974), S. 159-168 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucose oxidase (EC 1.1.3.4, from Aspergillus niger) has been entrapped in a crosslinked 2-hydroxycthyl methaerylate gel containing 20% poly(vinyl pyrrolidone). The kinetic behavior and thermal stability of the entrapped enzyme were found to closely approximate that of the free enzyme. The entrapped glucose oxidase shows a broadened pH profile which is attributed to a buffering effect of the gel. Stability of gel entrapped glucose oxidase is extremely good at room temperature, suggesting a variety ofanalytical and control uses for this system.
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  • 79
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    Biotechnology and Bioengineering 16 (1974), S. 881-896 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Spirulina maxima, a high protein alga, was grown in effluents from the London municipal waste treatment plant. Optimum growth conditions were developed, the composition of algae and the removal of nitrogen and phosphorus in effluents were studied. The advantages of this process in tertiary waste-water treatment and the quality of the single cell protein were investigated.
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  • 80
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    Biotechnology and Bioengineering 16 (1974), S. 933-941 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Oxygen supply is one of the main factors which influences aerobic cell growth in a fermentor. Maximal rates at which E. coli can grow on glucose as carbon source under various limiting oxygen-supply conditions were determined in a bench-scale fermentor. Culture conditions are described which gave yields of about 38 g dry cells per liter medium.
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  • 81
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    Biotechnology and Bioengineering 16 (1974), S. 991-995 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 82
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    Biotechnology and Bioengineering 16 (1974), S. 1359-1372 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A column reactor with an annular cross section was formed by rolling up DEAE cellulose paper and a screening spacer. Glucoamylase was attached by ion adsorption. For the spacer used, pressure drop was very low, suggesting that this form may be useful with feed streams that are not completely particle-free. Tests of this reactor at the high substrate concentrations characteristic of commercial reactors showed very little diffusional resistance, exhibiting zero-order behavior over most of the concentration range. At low concentrations, the reactor had an apparent “half-order” behavior caused by diffusional limitation in the paper. In this range, flow rate influenced the reaction rate, showing that mass transfer in the main stream also is a contributing factor in this range. Because of the high concentrations and the low Michaelis constant (0.0011 M) the reactor does not show first-order behavior, even at very high conversions. The design of a plant-scale reactor was formulated from these data. The increase in the quantity of enzyme necessary to compensate for the effects of diffusion was only a few percent.Two reactors were formed with sheets nonporous to the enzyme, binding the enzyme with cyanogen bromide after forming the reactor. The amount of enzyme bound was about one monolayer, and there appeared to be no diffusional limitations, even at low substrate concentrations.
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  • 83
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    Biotechnology and Bioengineering 16 (1974), S. 1413-1418 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 84
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    Biotechnology and Bioengineering 16 (1974), S. 1433-1447 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A high molecular weight intracellular enzyme of Bacillus brevis ATCC 9999 is released when the organism is disrupted by sonication of homogenization. However, both processes also degrade the enzyme. Assays for protein release and specific enzymatic activity of the released protein indicate that both release and degradation can be represented by first-order kinetic models. Utilization of the difference between the kinetics of release and degradation allows optimization in the recovery of this enzyme for both the sonication and homogenization processes.
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  • 85
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    Biotechnology and Bioengineering 16 (1974), S. 1507-1516 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ribulose-1,5-diphosphate carboxylase from spinach has been bound to arylamine porous glass with a diazo linkage and to alklamine porous glass with glutaraldehyde. Stability at elevated temperatures and responses to changes of pH and ribulose-1,5-diphosphate, Mg2+, and dithiothreitol concentrations were not significantly different from the soluble enzyme, though stability at 4°C was somewhat improved.
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  • 86
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    Biotechnology and Bioengineering 16 (1974), S. 1545-1547 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 87
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    Biotechnology and Bioengineering 16 (1974), S. 1557-1564 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 88
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    Biotechnology and Bioengineering 16 (1974), S. 1611-1631 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous fermentation of grape juice was studied in three basic kinds of nonmechanically stirred fermentors, classified according to the direction in which flow is applied against settling: upward-flow, slant-flow, and horizontal-flow.Fermentation kinetics were found to be zero-order, thus rate was directly proportional to cell density.Completeness of fermentation depends upon yeast characteristics (growth rate flocculation), fermentor geometry (settling depth, flow path length), and upon flow velocity.Fermentor analysis demonstrated that to achieve complete fermentation in the minimum juice holding time, efficient cell retention as well as rapid yeast growth and fermentation rates are required. Fermentor design and operation are discussed in the light of this analysis.
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  • 89
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: An electronic particle counter has been used to estimate the disintegration by freeze-pressing baker's yeast. A counter threshold level which just yielded the maximum count for intact cells was selected. The conductivity of the suspending medium was chosen such that maximum counts were obtained. Under these conditions, the electronic counts agreed well with the visual counts. At a certain threshold level the maximum count was obtained at a lower resistivity (higher conductivity) in the suspending solution with the freeze-pressed suspension than with untreated cells, indicating that damage to the permeability barrier may occur without disruntion of the cell envelope.Fresh baker's yeast cells do not behave as nonconducting particles. This has to be taken into account when volume determinations with electronic particle counters are performed.
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  • 90
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    Biotechnology and Bioengineering 16 (1974), S. 1345-1357 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many enzyme-catalyzed reactions involve the liberation or consumption of hydrogen ions. In this paper a mathematical model is employed to investigate how such reactions behave when the enzyme is immobilized. Shifted pH optima, disappearance of an optimum pH, insensitivity to bulk pH, and very large effectiveness factors are some of the phenomena which appear as a result of pH coupling between the reaction and the enzyme's activity. Several of the qualitative features revealed by the model are consistent with earlier experimental observations. In addition, preliminary guidelines for optimal choice of enzyme support are suggested.
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  • 91
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    Biotechnology and Bioengineering 16 (1974), S. 1393-1398 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 92
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    Biotechnology and Bioengineering 16 (1974), S. 1419-1423 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 93
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1449-1458 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic synthesis of nucleoside-5′-monophosphates from purineriboside, 6-mercapto-purine riboside, 6-methylmercapto-purine riboside, 6-chloro-purine riboside, tubercidin, 8-aza-adenosine, and 3′-deoxy-adenosine is described in gram scale. The synthesis is catalyzed by a phosphotransferase from carrots and uses phenylphosphate as phosphate donor. The reaction products are purified on QAE-Sephadex A25 columns. The large scale preparation of the enzyme is also reported.
    Additional Material: 4 Ill.
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  • 94
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1495-1506 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The soluble components in disintegrated cells of Saccharomyces cereivisiae have been characterized by means of extraction, centrifugation, dialysis, and gel filtration. The influence of alkali and heat treatment on the protein and RNA in the soluble fraction from disintegrated yeast cells and on functional properties of protein concentrates have been studied.After water extraction and centrifugation at 100000 g 42% of the nitrogen containing components of the disintegrated cells were recovered in the supernatant. By extraction at pH 11.5 an additional 31% of the nitrogen was solubilized. Half of the water-soluble nitrogen-containing components has a molecular weight lower than 5000. In the water- and alkali-soluble fractions about 80% of each amino acid was recoveredThe water-soluble protein was separated into 3 fractions by gel filtration on Sephadex G 200. The major portion of the protein had a molecular weight about 100,000. The amount of protein in this fraction was decreased after treatment at increasing pH and temperature. No degradation of protein to low molecular peptides occurred. The amount of RNA in the soluble fraction was only slightly influenced by alkali treatment and by heat treatment at pH 7.5 in the presence of 5% NaCl. RNA was not degraded to low molecular components of the treatments.The solubility of protein concentrates decreased after treatment at alkaline pH and after heat precipitation.
    Additional Material: 3 Ill.
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  • 95
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple system for the control of oxygen transfer in laboratory fermentation units has been devised. This system employs pure oxygen to elevate the driving force for oxygen transfer. In addition, the aeration is controlled in a closed loop manner in order to minimize total exit flow of the gas from the fermentor. Fermentation study using Bacillus stearothermophilus grown on n-dodecane at 55°C illustrates excellent carbon recovery as well as the ease of controlling oxygen transfer.
    Additional Material: 2 Ill.
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  • 96
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1565-1565 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 97
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Several microorganisms having higher L-histidine ammonia-lyase activity were immobilized into polyacrylamide gel lattice. The yield of enzyme activity by immobilization was highest in Achromobacter liquidum IAM 1667. As A. liquidum has urocanase activity, the cells were heat-treated at 70°C for 30 min to inactivate the urocanase.Enzymatic properties of the immobilized A. liquidum cells were investigated and compared with those of the intact cells. No difference was observed between the pH activity curve and optimal temperature for the intact and immobilized cells. The permeability of substrate or product through the cell wall was increased by immobilization of the cells.When an aqueous solution of 0.25M L-histidine (pH 9.0) containing 1mM Mg2+ was passed through a column packed with the immobilized A. liquidum cells at a flow rate of SV = 0.06 at 37°C, L-histidine was completely converted to urocanic acid. The L-histidine ammonia-lyase activity of the immobilized cell column was stable over 40 days at 37°C. From the effluent of the immobilized cell column, Urocanic acid was easily obtained in a good yield.
    Additional Material: 6 Ill.
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 77-97 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical treatment has been worked out for the kinetics of solid-supported enzyme systems, with diffusive and electrostatic effects taken into account. A utilization factor, defined as the ratio of the actual reaction rate to the rate of substrate consumption in the outer solution, is defined, and equations to evaluate the utilization factor are given for five kinetic conditions: (a) Michaelis-Menten behavior, (b) substrate inhibition, (c) product inhibition (competitive), (d) product inhibition (noncompetitive), and (e) product inhibition (anticompetitive). When the solid-supported enzymes obey a Michaelis-Menten relationship, an equation for the apparent Michaelis constant is given and a criterion for insignificant diffusion effects is shown. A substrate-inhibited enzyme reaction may display multiple steady-state behavior, and a criterion for uniqueness is presented. In the case of product-inhibited enzyme reactions, the utilization factor is always less than that which corresponds to a Michaelis-Menten relationship. Equations to evaluate the apparent Michaelis and inhibition constants are given.
    Additional Material: 13 Ill.
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  • 99
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The modeling of biological wastewater treatment processes has received much attention over the past ten years. Efforts are underway to develop a unified model for these processes which will greatly aid in the design and operation of wastewater treatment facilities. This paper presents a philosophical discussion of model building strategies augmented by a discussion of statistical problems associated with model parameter estimation and model discrimination. This discussion further illustrates with actual data, that goodness of fit is not a sufficient condition for model acceptance. Numerous rival models are examined to illustrate this point. In order to verify a model or to discriminate between rival models, they must be “Put in jeopardy.” If this attitude is not employed in model building efforts, important discrepancies in the proposed model may go undetected.
    Additional Material: 6 Ill.
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1197-1212 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Efforts were made to eliminate the influence of other factors as far as possible in order to obtain reliable results on the effects of oxygen on the growth of baker's yeast. A cultivation method is presented which permits the study of the effects of aeration intensity under conditions where the influence of catabolite repression is eliminated. A completely synthetic medium with glucose as the only carbon and energy source is also described.The capacity of yeast to perform aerobic metabolism varies when cultivated under different intensities of aeration. A clear maximum is observed for growth with 10% oxygen in the aerating gas mixture. Under conditions where catabolite repression does not function yeast has the potential for oxidative metabolism even under oxygen-limited growth. The main agent controlling the ability of yeast to support growth using only the oxidative metabolism is the available oxygen.At high oxygen tensions the metabolism is disturbed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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