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  • 1980-1984
  • 1970-1974  (73)
  • 1970  (73)
  • Biochemistry and Biotechnology  (73)
  • Nuclear reactions
  • 1
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The processing of fermentor-grown, edible yeast involves the removal of water. This can be accomplished through concentration followed by drum or spray drying. This study presents the essential physical properties of yeast solutions necessary for calculation of production economics. In addition, our initial studies of vacuum concentration show that some of the cell leakage necessary for good drying characteristics occurs. The residence time during concentration is also sufficient, to yield 1-2 log cycles of kill which are mandatory since the final product, should contain no viable cells.
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  • 2
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray-dried milk, 4-5 log cycles destruction occurred. The results indicate that, the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/°K mole to about 38 kcal/°K mole.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 145-154 
    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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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970) 
    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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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 157-158 
    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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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 159-166 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Streptomyces mannosidase, like the enzyme from other sources, is shown to require a divalent cation for enzyme activity. N-Ethylmaleimide pretreatment of enzyme-containing cells eliminated the requirement of aeration for enzyme activity. Methyl-α-D-mannoside was found to be a strong inhibitor of the hydrolysis of both p-nitrophenyl-α-D-mannoside and mannosidost reptomycin. The enzyme is bound at or near the surface of the cell and is inactivated by sonic oscillation. Small participate matter containing most of the activity can be released from the cells into water, such release being inhibited by phosphate, Tris, or sodium chloride.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 167-178 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The possibility to use microorganisms as human food is limited by several factors. The intact cell is resistant to digestion, the cell wall is unbalanced in essential amino acids, and the nucleic acids are said to be harmful. For using single cell protein as food it may thus be necessary to disrupt the cell wall and separate the protein from nucleic acid. This paper is concerned with the production and properties of extracellular enzymes able to lyse cell walls of microorganisms. Soil bacteria and actinomycetes have been cultivated and lytic enzymes from these organisms have been used to lyse living cells of the yeast like organism E. ashbyii. Efforts were also made to use these enzymes for lysing cell of a Methanomonas sp.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 179-212 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: B. subtilis NRRL B3411 neutral protease has been extensively purified by solvent, and salt fractional ion, pigment removal with DEAE-cellulose followed by chromatography on hydroxylapatite, and a final passage through a Sephadex G-100 column. The neutral protease was shown to be homogeneous by disc gel and cellulose acetate electrophoresis, gel filtration chromatography, and ultra-centrifugation. The molecular weight was determined by osmometry and ultracentrifugation to be about 38-42,000 and the amino acid composition and zinc content determined. The general properties of the enzyme, pH-activity relationship, stability, effect of inhibitors, and specificity are discussed. Comparative studies were carried out on the B. subtilis NRRL B3411 and B. subtilis var. amylosacchariticus neutral proteases and these enzymes were found to be indistinguishable by the methods used, but quite distinct from the thermostable enzyme thermolysin from B. thermoprotcolyticus.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 251-271 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The amylase of Bacillus subtilis NRRL B3411 has been purified and partially characterized. The specific activity can be increased from 300,000 units/g to 6,000,000 units/g with a 60% recovery of total units. The purified material consists of one major and one trace anodic component as determined by disc gel electrophoresis. The molecular weight was 48,000 as determined by bio-gel filtration; the molecular weight was 44,900 ± 2400 as determined by sedimentation equilibrium methods. This purified enzyme is stable at, 70°C in the presence of 0.01 M Ca++ and 0.1 M NaCl over a broad pH range from 5.5-9.5. The pH activity profile indicates optimum activity at pH 6.0. This amylase exhibits maximum activity at 60°C. The enzyme is a liquefying α-amylase as determined by analysis of hydrolysis products and immunological studies.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 213-249 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The alkaline proteases of B. subtilis NRRL B3411, B. pumilis, and B. licheniformis have been isolated by fractionation followed by ion exchange chromatography and their homogeneity demonstrated. General enzyme properties of the B. sublitis NRRL B3411 alkaline protease have been studied and attempts made to differentiate a group of alkaline proteases. It is clear that the alkaline proteases known as Subtilisins or Subtilopeptidases are not, exclusive to B. subtilis but are common to many Bacilli and therefore the generic name Bacillopeptidases has been proposed. It is clear too that on the basis of the effect of pH on activity, amino acid composition, esterase activity, and immunological cross-reactions the Bacillopeptidases can be divided into two groups or types: (a) Bacillopcptidase A (Subtilisin A or Subtilopeptidase A) which includes Subtilisin Carlsberg, B. licheniformis, and B. pumilis alkaline proteases; (b) Bacillopeptidase B (Subtilisin B or Subtilopeptidase B) which includes B subtilis NRRL B3411, Subtilisin Novo, Subtilisin BPN' (Nagarse), alkaline protease Daiwa Kasei, and (probably) B. subtilis var. amylosacchariticus. At present, no further differentiation is possible and whether or not the enzymes within group A or B are identical remains an open question. Methods for examination of crude enzyme mixtures or fermentation beers are described and from the examination of a number of crude enzymes and fermentation beers it appears that organisms producing Bacillopeptidase A do not produce neutral protease or amylase, while organisms producing Bacillopeptidase B produce a neutral protease and amylase as well.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 273-290 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The concept of a “critical oxygen concentration” is conventionally considered to hold for the submerged aerobic fermentation of glucose to gluconic acid. Above the critical level the fermentation rate is supposedly independent of oxygen concentration. In this work it is shown that, at a given agitation rate, the fermentation is independent of dissolved oxygen when above the critical. However, an increase in the agitation rate results in an increase in the fermentation rate. This increase was shown to be accompanied by an increase in the gluconolactone concentration in the broth. Gluconolactone, an intermediate in the reaction pathway, is hydrolyzed nonenzymatically to gluconic acid. Evidence is presented to suggest that the increased gas-liquid interfacial area brought about by increased agitation causes an increased net rate of lactone formation. This in turn results in an increased rate of hydrolysis of the lactone to gluconic acid. A model is presented hypothesizing that negatively charged cells adsorb at the gas-liquid interface. These cells attract hydrogen ions, causing a lowering of the pH in the film around the bubbles. It is this lowered pH which is considered to bring about increased fermentation rates when the interfacial area is increased. Supporting evidence is presented.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 291-311 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper is concerned with the study of an enzymatic system in a repeated batch process where the enzyme is subject to deactivation. The particular system studied was the enzymatic hydrolysis of Penicillin G to 6-aminopenicillanic acid. Utilizing standard optimization techniques, pH and temperature control policies were determined that would maximize the product yield.
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  • 13
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 313-319 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comparative study of the Bacillus subtilis neutral protease and Bacillus thermoproteolyticus thermolysin calalyzed hydrolysis of a few dipeptide sustrates including furylacryloylglycyl-L-leucine amide is reported. While differences in the kcat/Km were observed between the two enzymes toward substrates in which phenylalanine or leucine donated the amino group of the peptide bond, secondary effects of substituents on the carbonyl donating amino acid and pH profiles were quite similar. Differences were also observed toward protein substrates as compared to dipeptides.
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  • 14
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 321-331 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Through the use of pilot plant equipment, transaldolase types I, II, and III (from Candida utilis) have been separated and purified. The procedure includes a time sensitive solvent fractionation below 0°C, ion exchange chromatography, and crystalization. The enzyme yield represents a 41% recovery of crystalline type III and partially purified types I and II.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970) 
    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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  • 16
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 341-346 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The ecological significance of bacterial capsules when virulent bacteriophages are present was explored by exposing continuous cultures of Escherichia coli ATCC 11303, in various stages of capsulation and clumping, to a virulent coliphage, T2. Only partial protection was provided by capsulation, but this could be a factor affecting survival in complex mixed cultures.
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  • 17
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 333-340 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A microbial ecosystem represents a delicately balanced population of microorganisms each interacting with and influencing the other members of the population. An understanding of the nature and effects of these interactions is essential to improving the performance of these ecologies, which are important, in such diverse processes as biological waste treatment procedures, water pollution abatement, industrial fermentations, human or animal digestives processes and in soil. There are several types of mocrobial interactions, such as commensalism, inhibition, food competition, predation, parasitism, and synergism, which either singly or in combination may influence the functioning of the microbial ecology.To understand interactions, it is necessary to perform a detailed study of the physiology of the individual predominating microorganisms to establish their requirements with respect to such environmental factors as nutrients, temperature, pH, oxidation-reduction potential, removal of waste products, or toxic materials which may be involved in control processes and to determine how these factors affect their capabilities. The sum total of this information will indicate the possible interactions between the microorganisms and will form the basis for conducting experiments either in the laboratory or with mathematical models. Such experiments will lead to an understanding of microbial activities and to the formulation of control measures, often using an alteration of the environmental factors for regulation of the microbial ecologies. Extensive research remains to be done on the microbial interact inns in obtain the desired, precise control of these ecological processes.
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  • 18
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 353-378 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mathematical models of the interaction between predator and host populations have been expressed as systems of nonlinear ordinary differential equations. Solutions of such systems may be periodic or aperiodic. Periodic, oscillatory solutions may depend on the initial conditions of the system or may be limit cycles. Aperiodic solutions can, but do not necessarily, exhibit oscillatory behavior. Therefore, it is important to characterize predatory-prey models on the basis of the possible types of solutions they may possess. This characterization can be accomplished using some well-known methods of nonlinear analysis. Examination of the system singular points and inspection of phase plane portraits have proved to be useful techniques for evaluating the effect of various modifications of early predator-prey models. Of particular interest is the existence of limit cycle oscillations in a model in which predator growth rate is a function of the concentration of prey.
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  • 19
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 379-397 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The main purpose of the work reported here was to establish the effectiveness of aeration and agitation, and to determine the best conditions of aeration for the growth and production of glucose oxidase of Aspergillus niger, on a semi-industrial scale. Concentration of dissolved O2, O2 consumption and CO2 production were measured. It was found that the rate of growth and the activity of glucose oxidase per gram mycelium increased with the increase of speed of agitation. The concentration of dissolved oxygen of the fermentation broth, as well as the rate of respiration (O2 consumption and CO2 production) increased in direct proportion to the increase of speed of agitation, while assimilation of sugars was accelerated. The values of the respiratory ratio showed a fluctuation according to the presence or absence of sugar in the medium.
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  • 20
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 399-407 
    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 L-amino acid oxidase of Crotalus adamanteus was covalently coupled to porous 96% silica glass particles. The insolubilized enzyme was active on several L-amino acids including: leucine, isoleucine, cysteine, phenylalanine, tryptophane, and methionine. No activity was observed with D-amino acids, L-asparagine, or L-proline. Maximum activity was observed at pH 7.8. Stability of the enzyme derivative was demonstrated by continuous operation of an enzyme column for 35 days, during which the bound enzyme oxidized over 5000 times its own weight of substrate.
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  • 21
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bacteriophages are widely distributed in nature and may be important factors in regulating populations of their hosts. Model continuous culture systems of a single bacterial species and a temperate parasitic phage have been studied. Steady state cultures of lysogenic Escherichia coli 159T- (λcts) produced a small quantity of free λ cts phage. Temperature shocking such a culture resulted in a sharp increase in phage concentration with a concomitant fall in cell population. With time the system returned to a steady state condition.
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  • 22
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 409-417 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Earlier observations revealed that incubation of media and the attendant changes in oxidation-reduction potential (ORP) were related to improved cell production. This is a report, of work done to show that the higher levels and increased rates of growth of cells grown in incubated medium are associated with the ORP level of the medium before inoculation of the medium with cells. Work was done using 250-ml centrifuge spinner bottles as the culture vessels. Further work is needed to establish the desirability of deliberate poising of media prior to use for studies in small vessels and flasks.
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  • 23
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 419-428 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Previous studies of oxidation-reduction potential (ORP) variation in monolayer (Roux bottle) cultures pointed out the need for data on pH and ORP patterns in simple spinner cultures. This information was desirable for optimizing conditions of growth in small 1-L and New Brunswick fermentors. Results of experiments in 250-ml centrifuge spinner vessels are presented showing that incubation of media prior to inoculation induces desirable qualities reflected in better growth. The importance of initial ORP values of the medium is discussed. The relationship of ORP levels to yield and longevity of cell growth is also considered. The ORP level of the medium at inoculation is shown to be effected by previous incubation.
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  • 24
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 465-482 
    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 for analyzing the reactor behavior of a continuous, multistage tower fermentor is described. A model consisting of a system of interconnected, ideal subreactors is set up on the basis of the fermentor's configuration and flow pattern. The residence time distribution curve is used to test the validity of the model and the relative quantities of flow streams and regions in the model are determined. A least-square fitting procedure between measured and calculated distribution curves is used to identify the proper model. The application of this method to real cultivation conditions is also discussed. Using this approach, the multistage tower fermentor is shown to be equivalent to a cascade of four perfectly mixed tanks with a backtracking stream between stages. The extent of backflow under various conditions has also been determined.
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  • 25
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970) 
    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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  • 26
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In replicated 30 to 40-ml suspension cultures of rapidly proliferating monkey kidney cells of a comparatively fragile strain, the rates of glucose utilization and lactic acid accumulation averaged about 400 micrograms and 110 micrograms per 106 cells per day respectively, with average molar La/Gl ratios of 0.48. These two rates of glucose utilization and lactic acid accumulation were about 4 × and 10 × as high as the corresponding rates in comparable cultures of the hardier strain 2071-L mouse fibroblasts under the same conditions, with average molar La/Gl ratios of 0.16. In comparable but nonproliferating suspension cultures of the same strain of monkey kidney cells, during about 3 weeks the rates were extremely high, with about 710 micrograms glucose utilized and 445 micrograms lactic acid accumulated per 106 cells per day, with average molar La/Gl ratios of 1.37. The rates of glucose uptake and lactic acid accumulation were higher in the nonproliferating cultures aerated with 5% CO2 in air than in those aerated with 10% CO2 in air. This difference was associated with pH, which was higher in the former group.It was concluded that with this fragile strain of monkey Kidney cells(1) in nonproliferating cultures the cells were metabolizing actively but with a marked tendency to higher La/Gl ratios, (2) in the proliferating cultures the high rates of glucose utilization and lactic acid accumulation were definitely not directly correlated with the rate of growth, and (3) in none of the cultures was the amount of glucose remaining in the fluid at fluid changes so low as to have been a limiting factor.Information in the literature concering glucose utilization and lactic acid production by cells vitro is voluminous and in some respects contradictory. In the present study the rates were unexpectedly high for the monkey kidney cells, particularly those in the otherwise apparently inactive nonproliferating cultures. The data seem to be unique, in that an established strain of cells in chemically defined medium in suspension cultures has been characterized for these metabolic parameters in both proliferating cultures and in equivalent nonproliferating cultures under directly comparable conditions.The concept was developed that since these monkey kidney cells are obviously more fragile than the other cells examined, the complex physical stresses imposed upon these cells in agitated cultures can be modified and lessened in order to permit growth. Lessening of such mechanical stress waa brought about in several ways, of which only the smaller flask size seemed to be at least partly effective. Increasing either the concentration or the viscosity type of Methocel waa not effective.
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  • 27
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 483-500 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aerobiology studies at the Naval Biological Laboratory require use of a vacuum system to provide safe disposal of air contaminated with pathogenic, microorganisms. A system for thermal decontamination of this process air has been installed and tested. The system uses a natural gas burner to heat approximately 550 cfm of air to temperatures exceeding 750°F. Tests showed a reduction in number of acrosolized viable hardy spores (Bacillus subtilis var. niger) of more than 8 logs at design flow rates. The kill rate (D values) measured in this system is somewhat higher than those reported by other workers. The annual owning and operating cost of the system is approximately $9000.
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  • 28
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The microbiological extraction of zinc from a high-grade zinc sulfide concentrate has been investigated, using a pure strain of Thiobacillus ferrooxidans. Conditions such as temperature, pH, pulp density, nutrient, concentration, and specific surface of solids have been studied in terms of their effects on zinc extraction rate and in some instances on final zinc concentration in solution. Where appropriate, optimum conditions for leaching have been specified.
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  • 29
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    Biotechnology and Bioengineering 12 (1970), S. 519-539 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mechanisms and kinetic course of BOD exertion were compared in both open and closed systems. Two open reactors, a simulated stream device, and an open stirred reactor were employed, and the closed systems consisted of standard BOD bottles and 2.4-liter vessels. In the closed systems, both quiescent and stirred conditions of incubation were examined. Biological solids concentration, bacteria and protozoa concentration, substrate analysis, and chemical oxygen demand as well as biochemical oxygen utilization were employed to assess the performance of these systems.Oxygen uptake rate constants were observed to increase with increasing concentration o carbon source, thus militating against irect use of the usual dilution technique for predicting rate of deoxygenation in receiving streams. The relationship between specific O2 uptake rate and substrate concentration approximated a hyperbolic function similar to the Mono relationship for specific growth rate and substrate concentration. A technique using an open stirred reactor than the standard BOD bottle dilution technique is recommended.
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  • 30
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    Biotechnology and Bioengineering 12 (1970), S. 541-560 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A continuous symbiotic algal-bacterial system was developed consisting essentially of a mixed Chlorella-activated sludge culture which would efficiently remove nutrients from wastewater under aerobic conditions without supplementary aeration. Oxygen decline data were fitted to a mathematical model used to predict respiratory rates, photosynthetic oxygenation, and steady-state oxygen concentrations. Stable relative biological populations and a dissolved oxygen concentration of about 2 mg/1 were maintained during steady-state operation with daily harvesting of excess biomass. Respiratory and physiological relationships indicated that the carbon dioxide-oxygen balance is a primary control that governs the steady-state operation of a symbiotic algal-bacterial culture. The close association of the algae and bacteria resulted in an algal-bacterial floc with settled rapidly yielding a clear supernatant.
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  • 31
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    Biotechnology and Bioengineering 12 (1970), S. 561-575 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The stability characteristics of a continuous culture system were studied following the addition of the natural product inhibitor, ethanol. For a steady state culture of Klebsiella (Aerobacter) aerogenes there was a linear dependence of growth rate on ethanol concentration. Following impulse and step addition of the inhibitor, response patterns of the growth rate (μ) and overall metabolism (Qo2, QCo2, QAC) were observed. A mathematical model of the transient behavior of a product-limited system is proposed, and analog computer solutions fitted to the experimental data. The transient response of the growth rate could best be described by second or higher order equations, e.g., \documentclass{article}\pagestyle{empty}\begin{document}$$ T_2^2 \frac{{d^2 \mu }}{{dt^2 }} + 2T_2^2 \xi \frac{{d\mu }}{{dt}} + \mu = \mu _m (1.0 - q.P_t) $$\end{document} with values of the second order time constant (T2) = 5 min, and damping coefficient (ξ) = 0.4.
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  • 32
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    Biotechnology and Bioengineering 12 (1970) 
    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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  • 33
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    Biotechnology and Bioengineering 12 (1970), S. 1-17 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The precipitation of proteins with heteropolyacids has been studied for the purpose of large scale primary purification. A precipitate will form if the pH of the reaction between purified ovalbumin, hemoglobin, trypsin, pepsin, bovine serum albumin, ovomucoid, gelatin or ribonuclease and tungstrophosphoric, tungstosilicic or molybdosilicic acid is close to the isoelectric point of the protein and does not cause the dissociation of the heteropolyacid. Below the isoelctric point, the percent precipitation depends on the conformational changes of the protein. The precipitation of ovalbumin with tungstophosphoric decreases as the ionic strength of the buffer increases and is independent, of the protein concentration. Mixtures of ovalbumin and bovine serum albumin, though having close isoelectric points, can be separated by varying the concentration of the precipitant. The electropositive groups which combine with the tungstophosphoric acid are guanidino, ε-amino and imidazole. No precipitation is given by the α-amino groups. Filtrates of microbial fermentations containing lactase, glucose aerode-hydrogenase, alkaline protease, amyloglucosidase, and transglucosylase have been purified by precipitation with heteropolyacids.
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  • 34
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fungal cells from Curvularia lunata were entrapped in a crosslinked polyacrylamide gel. The gel-cells obtained as granules were applied in the microbial transformation of Reichstein compound S leading to cortisol through an 11-β-hydroxylation step. Some kinetic studies of this conversion using gel-cells were carried out. In addition, it was shown that gel-cell granules which had lost part of their 11-β-hydroxylase activity on storage could be reactivated yielding preparations with increased activity.From Corynebacterium simplex a steroid dehydrogenase catalyzing the Δ1- dehydrogenation of cortisol leading to prednisolone was isolated and partially purified. The preparation was entrapped in a crosslinked polyacrylamide gel and the gel-enzyme granules obtained used in steroid dehydrogenation processes.
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  • 35
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    Biotechnology and Bioengineering 12 (1970), S. 29-50 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of the batch-wise liquid-phase oxidation of ferrous sulfate by the organism Thiobacillus ferrooxidans has been studied over a range of temperatures from 20°C to 31°C and in the presence of an abundant supply of oxygen, carbon dioxide, and other nutrients.The rate of oxidation was found to be accurately described by the equation \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{dS}}{{dt}} = \frac{{\mu _m SX}}{{Y(K + S)}} $$\end{document} where t = time hr, S = concentration of ferrous ions g Fe++/1., μm = maximum specific growth rate of bacteria, hr-1. Y = mass of bacteria produced per gram of iron oxidized g/g, K = saturation constant, g Fe++/l., and X = concentration of bacteria g/1.The value for the maximum specific growth rate, μm, was found to vary from 0.12 hr-1 at 20°C to 0.20 hr-1 at 31°C, while the value for the saturation constant K varied randomly between 1 and 2 g/1.A method has also been described which permitted evaluation of the relevant rate constants μm and K without direct knowledge of the bacterial population. This method was found to yield values of μm and K which agreed with values determined accurately by a statistical regression analysis of the experimental data.
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  • 36
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    Biotechnology and Bioengineering 12 (1970), S. 51-61 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model of oxygen absorption in microbiological systems of zero order reaction rate is proposed. The partial differential equation was solved to predict the profile of the oxygen concentration boundary layer next to a gas-liquid interface. Generally speaking, the presence of microbial cells always helps to increase the oxygen absorption rate over that of physical absorption. Only when the microbiological reaction is slow as judged by the fact that the reaction time, tr, is much larger than the diffusion time, tD, can one rightfully approximate the oxygen absorption in microbiological suspensions by physical absorption.
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  • 37
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    Biotechnology and Bioengineering 12 (1970), S. 63-74 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A pilot-plant process has been developed for the continuous extraction and partial purification of prolyl-tRNA synthetase from mung bean. The bean slurry was wet ground in a hammer mill, clarified by two-stage centrifugation, and the protein in the effluent fractionated by precipitation at pH values of 5.2 and 4.2. The throughput was 13 kg dry bean/hr. The improved extraction process and reduced processing time resulted in an enzyme product with a specific activity 16 × that previously obtained in the batch process. The yield was also 50-60 times higher.
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  • 38
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    Biotechnology and Bioengineering 12 (1970), S. 75-84 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Xanthan biopolymer has been produced by single-stage continuous fermentation with Xanthomonas campestris NRRL B-1459 in a medium of glucose, minerals, distillers' solubles, and urea for as long as 20 days. At the highest dilution rate studied (D = 0.0285 hr-1), the steady state rate of xanthan production was 0.36 g/kg/hr and the steady state yield, basis glucose consumed, was 68%. Observations indicate that xanthan production rate is a function of pH and D.
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  • 39
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    Biotechnology and Bioengineering 12 (1970), S. 85-92 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucoamylase bound to DEAE-cellulose in 0.05 M sodium acetate, pH 4.0, is active in the conversion of starch to glucose. The activity of the DEAE-cellulose-bound enzyme ranges from 16 to 55% of the activity of the free enzyme. Binding of the enzyme narrows the pH optimum to approximately 4.0 and lowers the temperature optimum to 40-50°C as compared to a 60°C temperature optimum for the free enzyme. Concentrations of acetate buffer above 0.1 M disrupt the DEAE-cellulose-enzyme complex. Columns were used with some success for the continuous conversion of starch. Pretreatment of the starch with α-amylase and clarification were necessary to prevent blocking of the column. Columns maintained activity for more than 3 weeks of continuous operation.
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  • 40
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    Biotechnology and Bioengineering 12 (1970), S. 93-121 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Samples of oriented DNA prepared by wet spinning have been found to be very useful for physicochemical and biochemical studies with various techniques. The results obtained yield information on such fundamental properties of DNA as its hydration, electrical conductivity, and its interaction with irradiation and mutagenic and carcinogenic substances. Against this background a detailed description is given of the wet, spinning apparatus and of the techniques developed to produce bigger samples from spun films of oriented DNA. Photographic illustrations are used to give a clear picture of the various details. Extensions of the wet spinning method are discussed.
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  • 41
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    Biotechnology and Bioengineering 12 (1970), S. 141-143 
    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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  • 42
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    Biotechnology and Bioengineering 12 (1970), S. 1103-1109 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Enzymes subjected to shearing in a viscometer are partially inactivated. It is possible with viscometry to calculate the degree of inactivation that occura when an enzyme solution flows through a capillary tube. When shear rate × exposure time is less than 104, there is little or no inactivation.The masa average shear-rate × time or shear, for laminar flow in a cylindrical tube is simply 16L/3D. It is surprising that for a single pass through a tube, the masa average shear is independent of flow rate and shear rate.
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  • 43
    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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  • 44
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    Biotechnology and Bioengineering 12 (1970), S. 635-639 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Of several candidate disinfectants for use in tissue culture work, especially suspension cultures, sodium hypochlorite solution was selected to test its effect on growing cells. Metabolizing cells reduce, sodium hypochlorite oxidizes ; therefore NaOCl leakage into such systems must be neutralized with no untoward effects on the cells. Dilutions of routine disinfectant-grade sodium hypochlorite were tested against cell cultures. Those exposed to 15.62 to 31.25 ppm of NaOCl grew with no apparent cell damage.
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  • 45
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    Biotechnology and Bioengineering 12 (1970), S. 771-801 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 22 Ill.
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  • 46
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An enzyme kinetic model has been proposed to describe fermentation processes. This type of model was chosen because it is biologically sound, can incorporate all of the important engineering control variables, and can draw upon, in its development, the extensive kinetic literature. An intial qualitative test for this model was made on the gluconic acid fermentation. A necessary check of the model was that Monod's empirical cell growth and yield equations were derived as a special case. The model also offered an explanation for the hysteresis behavior of the gluconic acid production rate as a function of gluconolactone.
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  • 47
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    Biotechnology and Bioengineering 12 (1970), S. 845-847 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 48
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    Biotechnology and Bioengineering 12 (1970) 
    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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  • 49
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    Biotechnology and Bioengineering 12 (1970), S. 849-871 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two types of steam-sterilizable dissolved-oxygen probs were evaluated for use in fermentations. A galvanic-cell probe was selected over a polarographic probe because of its demonstrated ruggedness and dependability. Various methods for determining kLa in fermentors were compared and the oxygen balance method selected for use in viscous streptomycete fermentations. Rheological data are presented to identify a range of mash viscosity where many kLa measurement methods are not applicable. Oxygen transfer data are presented for streptomycete fermentations pilot fermentors.
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  • 50
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    Biotechnology and Bioengineering 12 (1970), S. 913-920 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In view of the recent development that some petrochemical products are efficiently available as substrates for the fermentation industry, glycerol manufactured from propylene by chemical synthesis would also be hoped for the purpose. This paper describes some of the factors influencing mannitol production from glycerol by Torulopsis yeasts and a microbial conversion of glycerol to D-fructose via mannitol, in which two sequential steps of yeast and Acetobacter fermentation are involved. Torulopsis mannitofaciens CBS 5981 and Torulopsis vcrsatilis CBS 1752, exceptionally good mannitol producers, were selected for the study. High concentrations of nitrogen sources and KH2PO4 in the medium markedly decreased mannitol yield in spite of good utilization of the substrate. T. mannitofaciens produced mannitol in yield of 31% of the glycerol consumed at optimal condition. The fermentation by washed yeast cells gave much higher mannitol yield of more than 50%. A sequential fermentation process was carried out without isolation and purification of the intermediate and yielded.51.7%. D-fructose from the glycerol.
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  • 51
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    Biotechnology and Bioengineering 12 (1970), S. 1001-1017 
    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 model is proposed for continuous stirred microbial culture system to explain observed deviations from the behavior predicted on the basis that the fluid is completely mixed, which arises from the use of radial flow impellers in such apparatus.
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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: Extended culture, a special type of semicontinuous culture, permits prolonged maintenance of a constant or programmed environment in a growing culture by a controlled addition of one or more substrates. Differences between extended culture and continuous culture data are a measure of differences in the properties of cell populations with different cell age distributions but identical steady-state environments. Both extended culture and continuous culture were used to study the growth kinetics of Candida utilis (ATCC 9226) under conditions of substrate inhibition at controlled concentrations of sodium acetate in a carbon-limited mineral salts medium supplemented with 0.01 g/1 yeast extract. Acetate concentrations ranged from 1.2 g/l to 10.8 g/l (expressed as acetic acid), while yeast concentrations varied from 0.3 to 7.8 (g dry cells)/1. Rate parameters such as growth yields (Y), specific growth rates (μ), and linear growth rates (K), were calculated by computer from the data and theory presented herein. Specific growth rates as high as 0.54/hr were observed, although extended culture growth was more nearly linear than exponential in these experiments. Growth yields usually varied between 0.2 and 0.4 (g dry cells)/(g acetate), although values were as high as 0.8 for a brief period during one experiment. Growth yields at a given acetate concentration were correlated by an equation of the form 1/Y = 1/YG + m/μ. A maintenance coefficient (m) of 0.17 (g acetate)/(g dry cell-hr) was observed at acetate concentrations of 4.5 and 10. g/1. A typical maximum growth yield (YG) of 0.51 (g dry cell)/(g acetate) was obtained at 4.5 g/1 acetate, but an unusually high YG of 1.33 was found at 10. g/1 acetate. Oxygen uptake measurements are compared with these cell yield measurements. Linear growth rates in expended culture were correlated by the equation K = 0.89-0.70 (S/S0) where K has units of (g dry cell)/(l-hr), S is the instantaneous acetate concentration, and S0 is the initial acetate concentration. The extended culture kinetic data are shown to be substantially different from continuous culture kinetic data. Reason for these differences are discussed in light of diffrences in the cell age distributions, as well as possible differences in experimental conditions.
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  • 53
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    Biotechnology and Bioengineering 12 (1970), 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: The effect of the rate of ‘natural death’ of bacteria on the steady state behaviour of continuous culture has been studied. A model which has no real biochemical basis but which gives good experimental correlation has been proposed. Populations of Acrobacter Acrogenes harvested from the chemostat at dilution rates greater than 0.1 HR-1 were found to be over 95% viable. The effect of the rate of death on the steady state yields becomes significant only at very low dilution rates. The experimental work of other workers has also been simulated to test the validity of the model. Theoretically it is also shown that an ‘apparent’ lag in batch cultures will be observed if the innoculum is of very low viability.
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  • 54
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    Biotechnology and Bioengineering 12 (1970), S. 591-601 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A kinetic analysis was made of the relationship between salicylate production from naphthalene and growth of Pseudomonas fluorescens in semicontinuous dialysis culture. The specific rates both of product formation and growth initially were increased by the diffusional withdrawal of salicylate, but subsequently were reduced to low levels despite continued salicylate removal. Productivity and growth were correlated by the Luedeking-Piret equation in an initial nondialysis period and in the early stages of dialysis fermentation, when specific growth rates exceeded. 005 hr-1. Below this level of growth at later stages of dialysis fermentation, the specific production rate was correlated only with total cell mass by a proportionality constant of .035 hr-1, which was attributed to maintenance metabolism. Maintenance accounted for about 84% of the total salicylate produced, while growth-associated metabolism accounted for the remainder.
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  • 55
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dialysis was attempted as a means to alleviate the product-activated controls presumed to limit the formation of threonine by an auxotrophic mutant of Escherichia coli strain W. The occurrence of inhibition rather than enhancement of yields by dialysis was traced to the fact that threonine actually was not inhibiting its own synthesis. Instead, α,ε-diaminopimelic acid became depleted, but the imbalance could not be corrected by exogenous replacement.
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  • 56
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    Biotechnology and Bioengineering 12 (1970), S. 633-634 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 57
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    Biotechnology and Bioengineering 12 (1970), S. 615-631 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In most enzymatic reactions, batch or continuous, separation of the enzyme for reuse is difficult if not impossible. A process will be presented in which an Ultrafiltration membrane serves to separate the reaction products from the enzyme and the substrate. In this manner the enzyme may be retained and re-used. Furthermore, under these conditions, the enzyme need only be present in catalytic amounts regardless of the amount of product produced.Under proper operating conditions and proper ultrafiltration membrane selection, a pure solution of α-amylase from Bacillus subtilis may be retained with no loss in enzyme activity over a test period of 30 hr after steadystate has been achieved. In the presence of substrate, the membrane support and ultrafiltration cell serve as the reaction vessel for the hydrolysis of starch. The substrate is continuously pumped into the cell under constant ultrafiltration pressure. The di-, oligo-, and polysaccharides formed from the enzyme reaction then either pass through the membrane as products or are retained. The molecular weight distribution of the products is dependent on the nominal molecular weight cut-off of the membrane, absolute ultrafiltration pressure, enzyme-to-substrate ratio, temperature, and residence time of the substrate in the reactor. In addition to the partial hydrolysis of starch by α-amylase, some preliminary findings on the complete hydrolysis of starch by glucoamylase will also be presented. In these latter studies, the substrate may be completely hydrolyzed to glucose units.
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  • 58
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 59
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    Biotechnology and Bioengineering 12 (1970), S. 679-712 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: High substrate concentrations inhibit growth and may distort the metabolism of microorganisms. Mechanisms causing substrate inhibition are discussed and used to derive several mathematical models representative of the entire concentration range, including stimulation of growth by low substrate concentrations. These kinetic models are tested with a variety of batch culture measurements of specific growth rate and respiration rate at widely-ranging substrate concentrations. Using one of the kinetic models, equations are developed for batch, continuous, and exponential-feed reactors. Comparison of results obtained in continuous culture with results from exponential-feed culture systems is shown to offer a novel experimental method for evaluating the effect of the cell age distribution on the properties and metabolic activity of a culture.
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  • 60
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    Biotechnology and Bioengineering 12 (1970), S. 651-677 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The utilization of an exogenous substrate by enzyme inside a bacterial cell can be limited by diffusion up to the cell, penetration of the cell, diffusion within the cell, and/or attack by internal enzyme. For small molecular weight substrates such as galactosides, and for bacteria such as Escherichia coli the diffusion steps are not rate limiting even with the permeases fully induced and the external concentration of substrate low. In permeaseless organisms with more than about 20 enzyme molecules per cell, permeation of O-nitrophenyl-β-D-galactoside through the membrane is limiting. Thus, a single initiation of transcription of a lactose message suffices to yield enough enzyme molecules to switch an uninduced cell from enzyme limitation to permeability limitation. Subsequent initiations change the cellular activity very little. This transition can be followed by assaying enzyme activity of both intact and lysed cell suspensions. In this way the induction response amongst cells in growing populations at high inducer concentrations has been found to be uniform. It was found that nearly all of the cells from balanced growing culture are immediately inducible even with doubling times as short as 7.6 hrs. At 24 hrs about 1/3 of the cells are inert at any time, but all cells synthesize enzyme within a 3-hour period. At low inducer concentration or in the present of catabolite repressor the rate of initiation is greatly decreased; this leads to a non uniform distribution of enzyme within the cells, which is readily detected by the experimental technique. In addition to developing the kinetics for enzyme contained in cells, the distribution of the enzyme among uninduced bacteria is presented.
    Additional Material: 9 Ill.
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  • 61
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 713-746 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this work, a mathematical model which can be used to describe butch growth in fermentations with two liquid phases present is developed for systems in which the growth limiting substrate is dissolved in the dispersed phase. The model takes into account the drop size distribution, the rate of adsorption of cells on the drop surface, the rate of desorption of cells from the drop surface, substrate transport between phases, phase equilibrium, and growth kinetics. The model also considers the effect, of coalescence and redispersion of oil drops in the system. It is assumed that the composition of the dispersed phase is such that substrate utilization from it causes little or no change in the interfacial area. A discrete uniform distribution and a discrete normal distribution which is obtained from an experimental distribution curve are used as drop size distributions. Simulation results are obtained for a wide range of parameter values using the IBM S/360 Continuous System Modeling Program.
    Additional Material: 23 Ill.
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  • 62
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 747-769 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A number of experimental studies on the dynamic, behavior of the chemostat have shown that the specific growth rate does not, instantaneously adjust to changes in the concentration of limiting substrate in the chemostat following disturbances in the steady state input limiting substrate concentration or in the steady state dilution rate. Instead of an instantaneous response, as would be predicted by the Monod equation, experimental studies have shown that the specific growth rate experiences a dynamic lag in responding to the changes in the concentration of limiting substrate in the culture vessel. The observed dynamic lag has been recognized by researchers in such terms as an inertial phenomenon and as a hysteresis effect, but as yet a systems engineering approach has not been applied to the observed data. The present paper criticizes the use of the Monod equation as a dynamic relationship and offers as an alternative a dynamic equation relating specific growth rate to the limiting substrate concentration in the chemostat. Following the development of equations, experimental methods of evaluating parameters are discussed. Dynamic responses of analog simulations (incorporating the newly derived equations) are compared with the dynamic responses predicted by the Monod equation and with the dynamic responses of experimental chemostats.
    Additional Material: 12 Ill.
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  • 63
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cellulase of Trichoderma viride was concentrated in various molecular cutoff membranes, and flux rates and retention of activity were studied under ultra-filtration conditions. Little or no Cellulase was discharged through the membranes tested. The concentrated (5-8-fold) enzymes were used to saccharify finely ground substrate (Solka Floe) in stirred tank (STR) and membrane reactors (MR). A pressure filtration vessel provided with a membrane for simultaneous removal of low molecular weight products (glucose) from the reacting system (Cellulose-Cellulase) is designated as a membrane reactor. Continuous digestion of dense cellulose suspension in the membrane reactor was achieved. Using PM-30 (Amicon) membrane reasonably high mass flux values (9.7-23.3 gals/ft2 - day) were obtained in separating glucose from a digest of 30% cellulose suspension. Abcor membrane (HFA 300) was equally effective and necessitated less care in handling. Nearly 14% glucose concentration has been achieved in less than 50 hrs in STR by digesting a 30% cellulose suspension. Based on experimental data a model system is proposed for the continuous steady state Saccharification of ground substrate in which there is continuous removal of concentrated glucose syrup, and a feedback of enzyme.
    Additional Material: 10 Ill.
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  • 64
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 947-959 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to isolate proteins from microalgae, yeasts and bacteria, cell disintegration in a special ball-mill was performed. The degree of disintegration of the different microorganisms was compared. The dependence of disintegration on bead size and on the ratio between the volume of suspension and the volume of glass beads was also investigated. Nondisintegrated and disintegrated cells were extracted with sodium hydroxide and the amount of extractable nitrogen and the amount of nitrogen precipitable at pH 4.0 were determined. The dependence of yield on the sodium hydroxide concentration, extraction time, and temperature was studied. When extracting undisintegrated cells, very low yields were obtained and the nitrogen extracted was mostly nonproteinous. For disintegrated cells high yields were obtained. An optimum was found after extraction with 0.3-0.5% sodium hydroxide; at pH 11.0-11.5. The precipitate obtained represented 60-70% of the cell nitrogen. The nitrogen content of the precipitate was 12-14% of the dry weight.
    Additional Material: 8 Ill.
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  • 65
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gram-sized quantities of purified arginine, formylmethionine, glutamic acid, and phenylalanine-2 tRNAs have been prepared from pools of E. coli K-12 MO7 mixed tRNAs by reversed-phase chromatography after preliminary fractionation on DEAE-cellulose. Purified formylmethionine tRNA and partially purified arginine tRNA and glutamie acid tRNA were obtained from large-scale RPC-3 runs (4 × 36 in. column). The arginine tRNA was further purified by rechromatography on RPC-4 columns, and the gluatmic acid tRNA by rechromatography on an RPC-3 column. Two phenylalanine tRNAs were resolved on large-scale (2 × 96 in. column) RPC-3 runs; only the second phenylalanine tRNA reached a satisfactory degree of activity. About 0.88 g of arginine tRNA, 70% activity; 3.32 g of formylmethionine tRNA, 97% activity; 0.80 g of glutamic acid tRNA, 83% activity and O.92 g of phenylalanine-2 tRNA, 78% activity, were produced. The processing steps employed are reliable and reproducible and the procedure is amenable to routine production of these tRNAs.
    Additional Material: 9 Ill.
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  • 66
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 961-974 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growth and lactic acid production by L. delbrueckii was studied in a dialysis culture system and the inhibitory effect of lactate confirmed by removing lactate from the culture medium by dialysis. It has been shown that lactate inhibits growth after the log phase and that the maintenance of low lactate concentrations after this point permits higher specific growth rates and higher maximum cell concentrations. Acid production is also significantly higher in a dialysis culture system. Finally, a modification of the Luedeking-Piret model, incorporating the lactate inhibition effect, is proposed.
    Additional Material: 14 Ill.
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  • 67
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 577-589 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The conversion of naphthalene to salicylic acid by Pseudomonas fluorescens was studied as a model for dialysis fermentation. In a demonstration experiment, the continual removal of the product by dialysis and by intermittent replenishment of the dialysate reservoir caused cyclical changes in the concentrations of viable cells and product. The cumulative total amount of both cell mass and salicylate, however, continued to increase steadily until the experiment was terminated after 15 days. At this time the rate of product formation was highest and still increasing, although less than 10% of the cells were viable. The terminal amount of salicylate was about 20-fold greater than the maximum reached in the control fermentation, and was calculated to be 2.6-fold more productive even if the control were optimally recycled. Methods were projected to achieve still further improvements.
    Additional Material: 4 Ill.
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  • 68
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 641-644 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Tab.
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  • 69
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970) 
    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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  • 70
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 803-830 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two kinds of mathematical models have been developed for batch penicillin fermentations: (1) general models, based on averaged, nondimensionalized cell and penicillin synthesis curves from plant, scale fermentors and (2) particular models developed from specific sets of experimental data from two sources. Parameter-temperature functions used with the general models were assumed to have general shapes which could apply to many fermentations, i.e., they were based on the familiar temperature response of enzyme-catalyzed reactions. Parameter-temperature functions for the particular models were determined from experimental data for batch runs at various temperatures.
    Additional Material: 14 Ill.
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  • 71
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 873-887 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The removal of cellular material from fermentation broths is of importance in many fermentation processes. The present work compares the performance of recently developed polyelectrolyte flocculating additives with traditionally available additives. Objectives are to establish criteria for the choice of a flocculating additive and establish optimum conditions for the formation of stable, fast settling floe, and for quantitative separation of cellular material from the medium. Fermentation broths of actively growing Candida intermedia were used to evaluate the effectiveness of fifty commercial flocculating additives at different dosages and pH values. Certain strong anionic and strong cationic polyelectrolytes and mineral hydrocolloids were found to be most effective in their enhancement of settling rates. Some differences in behavior exist between glucose grown cells, hydrocarbon grown cells, and washed cells in buffer suspension. Flocculation of cells from fermentation broths is concluded to be highly dependent upon adsorbed material. A high charge density to interact or compete with adsorbed material and a solubility in the adsorbed material are important factors in choosing an additive for a given application. The fluid mechanics of a flocculating suspension is an important variable since low shear does not provide adequate contacting between cells for floe formation and high shear leads to floe breakup. An apparatus was constructed to grow floe under constant fluid mechanical conditions both in laminar and turbulent flow regimes. Turbulent shear was found to be very important in forming large, compact floe in cases where irreversible ionic bridging is the mechanism as for the strong anionic polyelectrolyte, polystyrene sulfonate. Adequate mixing is required to disperse the flocculating additive, but the level of turbulence is relatively unimportant in cases where reversible colloidal bridging is the mechanism as for the mineral hydrocolloid, bentonite.
    Additional Material: 4 Ill.
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  • 72
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of mixing on the critical mean holding time for washout and the steady state performance of growth processes in continuous flow reactors are investigated. Macromixing, micromixing, and cell recycle arc considered. The tanks-in-series model composed of N completely mixed flow reactors, the dispersion model, the plug flow model, and a combined model composed of a plug flow reactor and a continuous stirred tank flow reactor connected in series arc used to represent the macro-mixing or residence time distribution. The extreme cases of micromixing, namely, complete segregation and maximum mixedness, as well as intermediate states of micromixing are investigated to determine their effects on washout and the occurence of multiple steady states. A technique for predicting the maximum mixedness washout condition from a knowledge of the residence time distribution is presented and used to determine the washout condition for the dispersion model under maximum mixedness conditions.
    Additional Material: 10 Ill.
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  • 73
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 1081-1098 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Optimization methods based on the continuous maximum principle and the calculus of variations were used to calculate optimum temperature profiles for batch penicillin fermentations. These methods were first applied to several general models to develop effective techniques for the numerical solution of the equations. Subsequently, these methods were applied to two particular models, derived from experimental data, and the optimum temperature profiles were determined. The results indicated that an improvement, in penicillin yield of about 15% was possible if the optimum temperature profiles were followed.
    Additional Material: 9 Ill.
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