Library

Notes: In situ hybridization with fluorescently monolabelled rRNA-targeted oligonucleotide probes (17 to 18 nucleotides) was used to discriminate between Alcaligenes eutrophus JMP 134 and Acinetobacter calcoaceticus 69-V by flow cytometry. The strains were grown in batch experiments in a mixed population. The forward light scatter and fluorescence of each bacterial cell were measured with a single laser cytometer. The intensity of fluorescence after rRNA staining depended on the content of ribosomes, which correlated with the growth rate of bacteria. Therefore exponentially growing cells could be clearly detected. For other growth phases, signal amplification was necessary using multiple probes. The two bacterial strains were identified with differently labelled probes under an epifluorescent microscope. Using a single laser cytometer, rRNA based identification was possible nut not ideal. Better discrimination between the two strains of the mixed population was achieved by DNA staining, combined with the different forward light scatter signals. Due to the significantly different cellular DNA and GC content of both strains, the fluorescent dye DAPI (4′, 6-diamidino-2-phenylindole), preferring AT-rich regions of DNA, was found to be a supplementary tool for population analysis. The abundance ratios of the two strains in mixed culture determined by DNA or rRNA staining were similar.

Notes: The process of leachate denitrification by populations of nitrifying and denitrifying bacteria was investigated. Leachate, derived from a local municipal landfill site, was nitrified in a continuously operating packed-bed biofilm reactor and thereafter denitrified in an activated sludge bioreactor. To follow the progress of nitrogen elimination, ammonium, nitrite and nitrate concentrations were determined at all stages of the process. While the nitrite and nitrate concentrations were measured by conventional colorimetric methods, computer controlled coulometric titration with in situ generated hypobromite was used for ammonium determination, which had previously been selectively separated from the sample matrix by gas dialysis. The detection range of the method was from 1 × 10-6 to 1 × 10-3 M ammonium (relative standard deviation (RSD) = 2%, n = 6). No interference of the complex sample matrix was found in ammonium determination. The average ammonium concentration in the leachate was 409 mg/l (standard deviation (SD) = 142 mg/l, n = 55). The ammonium concentrations decreased to 1-5 mg/l during nitrification under continuous operating conditions. Increased ammonium concentrations after nitrification correlated with a decrease in the efficiency of nitrogen elimination by up to 45% due to the build-up of high concentrations of nitrite. The concentration of sulphides, another source of pollution of the leachate, was also determined by triangle programmed coulometric titration. The average concentration of sulphides in the leachate was 221 mg/l (SD = 374 mg/l; n = 55). The sulphide concentrations decreased to concentrations below the detection limit of the coulometric titration (2 × 10-6M) during nitrification.

Notes: An enzymatic membrane for application in the processes of decomposition and removal of urea from aqueous solutions was prepared: jack bean urease was immobilized on an aminated polysulphone membrane by adsorption. The inhibition of the system by boric acid was studied using procedures based on the MICHAELIS-MENTEN integrated equation (non-linear regression, and the linear transformations of WALKER and SCHMIDT, JENNINGS and NIEMANN, and BOOMAN and NIEMANN). The reaction was carried out in a 100 mM phosphate buffer of pH 7.0, containing 2 mM EDTA, obtained by neutralization of orthophosphoric acid with NaOH, at an initial urea concentration of 10 mM, and a temperature of 25 °C. The reaction was initiated by the addition of the enzyme to the urea solution, and was monitored by removing samples of the reaction mixture for NH3 determinations by the phenol-hypochlorite method until the urea was exhausted. The results were compared with those obtained earlier under the same reaction conditions for free urease and urease covalently immobilized on chitosan. The inhibition was found to be competitive, similar to that of the free enzyme and urease immobilized on chitosan, with inhibition constants Ki equal to 0.36, 0.19 and 0.60 mM. The results show that adsorption of the enzyme on a polysulphone membrane changed the enzyme to a lesser degree than covalent immobilization of the enzyme on a chitosan membrane.

Notes: Investigations were conducted with the aim of producing extracellular lipase from Candida rugosa by solid-state fermentation (SSF), using coconut oil cake (COC) as a solid substrate. To optimize production, various modifications were made to enrich the substrate by supplementing it with mineral solution, different carbon sources and several inorganic as well as organic nitrogen sources. Among them, urea (1%), peptone (3%) and maltose (5%) were found to be most suitable. Addition of olive oil (10%) encouraged lipase synthesis. The maximum lipase activity in the enriched substrate was 87.76 units per gram of dry fermented substrate [U/gds] compared to 25.81 U/gds in the raw cake at 96 h of fermentation, and growth was as high as 14.44 mg/gds of glucosamine. This was reached at 72 h in the enriched substrate. C. rugosa growth was calculated indirectly by estimating the glucosamine content in the cell wall after its hydrolysis. The enzyme yield was far better than any values reported as yet.

Notes: In this work, an immobilization method for polymer-levan production by a non-flocculating Z mobilis culture was developed. The extent of cell attachment to the stainless steel wire surface, culture growth and product synthesis were described. It was established that during short-term passive immobilization of non-flocculation Z mobilis cells on a stainless steel wire surface, sufficient amounts of biomass for proper levan and ethano fermentation could not be obtained. Adherence of cells was improved by pressing the paste-like biomass within stainless steel spheres knitted from wire with subsequent dehydration. Biomass fixed in metal spheres was used for repeated batch fermentation of levan. The activation period of cells within wire spheres (WS) was 48 h in duration. During this time, cell growth stabilized at production levels of ethanol and levan of Qeth = 1.238 g/l × h and qeth = 0.47 g/l × h; Qeth = 0.526 g/l × h and qeth = 0.20 g/l × h. Five stable fermentation cycles were realized using one wire sphere inoculum, and maintaining a stable ratio of 2.4 of biomass suspended in the medium to biomass fixed in the sphere. Using fixed Z mobilis biomass in the WS, the total amount of inoculum could be reduced for batch fermentation. Large plaited wire spheres with biomass may have potential in fermentation in viscous systems, including levan production.

Notes: This review is concerned with the application of hairy roots, i.e. plant roots formed from plant cells after transformation by Agrobacterium rhizogenes for the production of bioactive compounds. Transformed root cultures have been established from numerous species of dicotyledonous plants. The plants, as well as the main products accumulated in hairy root cultures derived from these plants, are listed in this paper. Data are presented on novel compounds, hitherto detected only in transformed roots but not occurring in the corresponding intact plants.The possible use of hairy root cultures for the over-production of secondary metabolites and biotransformation of chemicals is discussed. In order to enhance the productivity of hairy root cultures, various methods have been derived, and optimized procedures are proposed. They include selection of high-producing clones, elicitation, composition of growth media, culture conditions and genetic approach. Hairy roots usually store secondary metabolites in vacuoles inside the cells. Therefore, several methods have been used to increase the amount of products released into the medium. Unfortunately, no general procedure is known that works in all cases, and the excretion behaviour of hairy root cultures varies from one species to another and even within one species from one clone to another.Special attention is given to the cultivation methods and bioreactor systems for hairy root cultures. Hairy roots are cultivated usually in shake flasks; however, shake flask culture is not suitable for the complex optimization and continuous control of the culture conditions. In this paper, we are going to present bioreactors proposed for the cultivation of hairy roots under more or less controlled conditions. Modifications of typical bacterial bioreactors, i.e. stirred tanks, airlift loop reactors and other constructions, are presented. A very special type of bioreactor providing good conditions for loose root mass multiplication without oxygen or substrate limitations, is the mist bioreactor. Nowadays, it is practically impossible to select the one best bioreactor type for hairy root culture.

Notes: Hydrolyses of olive oil were performed in a reactor with lipase immobilized on a laboratory ultrafiltration poliamide-6 membrane. The reactor consisted of two circulating phases of olive oil and buffer solution. For the characterization of the reactor performance, a model of the hydrolysis process was developed. It was created by means of thermodynamic network representation of both the chemical processes and the transport of the reactants. According to an estimated bond graph network, the model is represented quantatively by a set of thirty-three differential equations representing the time derivatives of the particular species concentration. The parameters of the model were estimated based on experimental data and/or literature notations. Close agreement of numerical estimations of the product concentrations with experimental data was gained. The model enabled an extended analysis of the influence of different reaction parameters, enzyme inhibition and concentration of the reactants on reactor performance.

Notes: The effects of anoxic conditions on product inhibition and the stability of L-ATC hydrolase were investigated in the conversion of D,L-2-amino-Δ2-thiazoline-4-carboxylic acid (D,L-ATC) to L-cystine using the cell free extract enzyme of Pseudomonas sp. in the presence of hydroxylamine. At L-cysteine equivalent levels, where one mole of L-cystine was counted as two moles of L-cysteine, L-cystine inhibited the L-ATC hydrolase reaction to a greater extent than L-cysteine. In air, the product occurred predominantly as L-cystine (94.9%), whereas in a nitrogen atmosphere the product occured as a mixture of L-cysteine (39.3%) and L-cystine (40.7%). As a result, less product inhibition took place in nitrogen. The activity of L-ATC hydrolase was almost fully lost after 20 h of incubation by shaking at 30 °C in air, but considerable activity remained under the anoxic conditions of nitrogen. A kinetic analysis of the reactions confirmed that reduced product inhibition and enhanced enzyme stability in nitrogen result in a more efficient enzyme reaction. The inactivation rate constant (k1) was estimated to be 0.11 h-1 in nitrogen and 0.22-1 in air, indicating that the stability of L-ATC hydrolase in nitrogen was greater than in air. The values of the Kp1 and Kp2 constants related to product inhibition were 43.36 mM and 30.48 mM for L-cysteine and L-cystine, respectively, where higher values were an indication of less product inhibition. The value of the rate constant (k2) for the oxidation of L-cysteine to L-cystine was 0.09 h-1 in nitrogen and 1.01 h-1 in air, suggesting that the oxidation of L-cysteine to L-cystine proceeds faster in air than in nitrogen.

Notes: Enzymatic stereoselective hydrolysis of (R,S)-1-phenylethyl propionate was performed in a stirred tank and in a biphasic enzyme membrane reactor. Lipase from Pseudomonas sp. was proved to be a good enantioselective catalyst for this reaction. The enzyme was covalently immobilized in a porous polyamide membrane (flat sheet as well as hollow-fibres) via glutaraldehyde. An influence of membrane hydrophobicity on reactor performance was observed. Initial lipase activity and productivity in the processes were equal to 1.05 × 10-4, 1.3 × 10-5 and 1.0 × 10-5 mole/(h × mg of enzyme) in the case of native lipase, in the aromatic polyamide hydrophobic membrane reactor and in the hydrophilic polyamide-6 membrane reactor, respectively. The influence of some factors such as temperature, pH, buffer concentration, initial substrate concentration and addition of β-cyclodextrin derivatives on reaction rate and enantioselectivity was investigated and discussed. In the enzyme membrane reactor both organic and aqueous phases circulated countercurrently on both sides of the membrane. At a conversion degree of under 55-60%, pure enantiomer of the remaining ester (i.e. 〉 98%) was obtained.

Notes: A real-time artificial intelligence method for controlling the concentration of dissolved oxygen is proposed.Two projection versions of algorithms are considered in this paper. The versions vary in structure of the intelligent agents. One of the agents represents an automaton of expedient behaviour, the structure of the other consists of two automata which behave expediently in a complicated random medium.The first algorithm holds a check on a trend of change in values. The second version of the algorithm takes into account both the trend of change in the values and the speed of change in the values.Simulation studies show that expedient behaviour of the automata in the random medium for the control of dissolved oxygen concentration can bring about a good performance.

Notes: The production of L-glutamic acid with Corynebacterium glutamicum under biotin limitation was studied. Assuming a formal type of cell maturation, an adequate formal kinetic model was developed. This model includes growth, dependent on biotin, and uses the same retention term for describing the lag phase and cell maturation. Special attention was paid to the graphical interpretation of the performance between the variables, which is relevant for kinetics. Comparison between experiments and the model resulted in different degrees of agreement. However, the main trend of the experimental patterns of the complex bioprocess can clearly be mirrored in this model.

Notes: Bacterial strains have been isolated from contaminated concrete debris which exhibit the metabolic capability to degrade 2,4-chlorinated and 4-chloro-2-methyl-substituted phenols and phenoxyalkanoic acids including phenoxyacetate and phenoxypropionate derivatives. These strains were taxonomically identified. Two of them were found to belong to the β-subgroup of the proteobacteria and showed strong similarity to Rhodoferax fermentans. Preliminary investigations by PCR amplification using respective primers revealed that the strains harbour tfdA-like gene sequences.

Notes: The cell suspension culture Daucus carota L. was permeabilized by Tween 80 and immobilized by glutaraldehyde. β-Galactosidase showed an optimum pH of 4.7 and an optimum temperature of 55 °C. The enzyme hydrolysis was linear for 3 h, reaching a 65% conversion. A very good level of storage stability was achieved when using dry catalyst, or a solution of 0.15 M NaCl with the addition of chloramphenicol, (l-methyldodecyl)-dimethylamin-4-oxide (ATDNO), chlortetracycline hydrochloride (CLCTC) or by freezing the immobilized cells in 0.15 M NaCl. The cells characterized by high enzyme activity and stability in long-term storage showed convenient physicomechanical properties.

Notes: A new finite-state method is proposed which has been designed for use in biotechnological processes, in particular for the control of the pH in acidic waste water.The automation of expedient behaviour takes into account the non-linear character of the process and a good control stability in spite of variations in the influent acidic concentration, dissociation constant of the acid and change of the pH set point.To design the controller with the proposed method, no model of the process is required. Simulation studies show that expedient behaviour of an automaton in a random medium for the control of the pH neutralization process can give a good performance.

Notes: Cells of an Actinomycete-like bacterium, strain GJ70, with the ability to degrade several haloalkanes were used as a biological component in a discontinuous microbial bioassay for the detection of 1,3-dichloropropene and 1,2-dibromoethane in water. The cells were entrapped in different matrices such as calcium alginate, carrageenan, chitosan, polyacrylamide-hydrazide and chitosan-carboxy-methyl cellulose; the specific dehalogenating activity of the immobilized cells to a stirred sample solution and by the use of an ion selective electrode (ISE) for the quantification of enzymatically released halogen ions, the concentration of halogenated hydrocarbons could be estimated by determining the change of electrode potential within a period of 5 min. The detection limits for 1,3-dichloropropene and 1,2-dibromoethane were below 100 μg/l and 25 μg/l, respectively; the relative standard deviation was 〈 10%. In addition, several chlorinated and brominated hgydrocarbons were converted by the bacterial cells at a reduced rate e.g. 1, 2-dibromopropane, 1-bromoethane, 1,5-dichloropentane, etc. Moreover, temperatures of between 20 and 40%C did not affect the enzymatic activity of the cells, and a pH of between at 5 and 9 had little influence. Several organic substances and non-metabolizable compounds did not affect the conversion, whereas some heavy metal ions acted as inhibitors.

Notes: Forty-two white-rot fungi isolated in South America were incubated with long fibre sugar cane bagasse (LFB). The residual composition of LFB was determined after white-rot decay at 30 and 60 days. The ratio of residual lignin to residual lignin to residual cellulose (RL/RC) of untreated material (LFB) was 0.48. After white-rot-decay, the residual material with lower RL/RC ratios indicated that mainly lignin was degraded. In only 30 days, Phlebia sp. MVHC 5535, Athelia sp. MVHC 5509 and Spongipellis pachyodon MVHC 5019 caused a decrease in the RL/RC ratio to 0.36, 0.37 and 0.38, respectively, while it took 60 days for Ganoderma applanatum MVHC 5347, Hyphodontia sp. MVHC 5544, Panus tigrinus MVHC 5400, Stereum sp. MVHC 5113, Phellinus punctatus MVHC 5346 and MVHC 6388 to reach a ratio lower than 0.40. No correlation was found between the amount of some ligninolytic enzymes secreted and the residual composition of bagasse after white-rot fungi fermentation. Most of the fungal strains caused an increase in the relative amount of residual cellulose, indicating that hemicellulose was the preferred energy source.

Notes: A poppy cell suspension culture was permeabilized by Tween 80 and immobilized by glutaraldehyde. The α-Galactosidase in these cells showed an optimum pH level at 5.2 and an optimum temperature at 70 °C. Enzyme hydrolysis was linear for 3 h, reaching 86% conversion. A very good level of storage stability was achieved when using dry catalyst and immobilized cells in 0.15 M NaCl solution (with the addition of chloramphenicol, [1-methyldodecy1)-dimethylamin-4-oxide (ATDNO), chlortetracycline hydrochloride (CLCTC)] or by freezing them in 0.15 M NaCl solution.

Notes: R. opacus UFZ B 408 is able to use pyridine, a potentially growth-inhibiting substrate, as the sole source of carbon, energy and nitrogen. In a previous publication [1] we reported that with the simultaneous utilization of a second carbon and energy source in carbon-substrate-limited chemostat culture, stable steady states could be achieved at higher dilution rates than with growth on pyridine as the sole substrate. Owing to the higher growth yield during growth on such a substrate mixture, both the specific pyridine consumption rates and the residual pyridine concentrations were lower at similar dilution rates than with growth on pyridine alone. Therefore, the critical growth-inhibitory pyridine concentration was only achieved at a higher dilution rate.With the investigations presented here in carbon-substrate-limited continuous culture, the simultaneous utilization of pyridine and formate by R. opacus UFZ B 408 was studied. The yield coefficient during growth on pyridine as the sole substrate amounted to about 0.55 g dry mass/g pyridine. Theoretically, however, the carbon-metabolism-determined yield coefficient should have been about 0.915 g dry mass/g pyridine. Because of the difference between these two values the conclusion was drawn that pyridine is energetically deficient. That means that during growth on pyridine a part of the substrate was dissimilated to supply the energy required for the incorporation of the pyridine carbon into biomass. Formate cannot be used as a carbon source for growth by R. opacus UFZ B 408. However, with growth on pyridine, formate was oxidized simultaneously. During growth on pyridine/formate mixtures, the yield coefficient could be enhanced up to 0.7 g dry mass/g pyridine. That means that biologically usable energy, generated in the course of the formate oxidation, was used for the assimilation of pyridine carbon. The increase in the yield coefficient was related to the utilization ratio of formate to pyridine in a linear manner. However, the carbon-metabolism-determined yield coefficient of 0.915 g dry mass/g pyridine could not be achieved. That can be put down to the fact that R. opacus UFZ B 408 possesses only a limited capacity to oxidize externally supplied formate. Because of the limited formate oxidation capacity the probability is low that, with simultaneous utilization of formate, stable steady states could be achieved at substantially higher dilution rates than with growth on pyridine alone.Enzymatic studies revealed the induction of both NAD(P)+-linked glutaric dialdehyde dehydrogenase and isocitrate lyase during growth on pyridine. Therefore, the conclusion was drawn that pyridine is metabolized by R. opacus UFZ B 408 via the same pathway described for the utilization of pyridine by Nocardia Z1 [2]. This conclusion implies that the ability to oxidize formate represents a metabolic performance which seems not to be directly related to the pyridine metabolism of R. opacus UFZ B 408.

Notes: Hydrolysis and transformation of Fibrenier cellulose (USA) with enzymes from Aspergillus niger IBT-90 was studied. The process was performed at 50°C and pH 4.8 for 24 h using an enzyme complex either as a properly diluted culture filtrate or as a mixture of isolated and purified enzymes from A.niger IBT-90. In the latter experiments, enzyme-substrate ratios expressed as units of activity per 1 g of cellulose were as follows: endoglucanase E1 and E2, 40; β-glucosidase, 40 and cellobio-hydrolase, 2. Cellulose concentration was 5%. It was proved that the crude celluloytic complex from A. niger IBT-90 exhibits higher efficiency in the decomposition of cellulose in comparison to the mixture of enzymes isolated from this complex, as was revealed in assays of reducing sugars and determinations of light transmission throughout cellulose fibres using a computer analysis of the microscopic image. Comparison of both the endoglucanases E1 and E2 showed that the first enzyme is more active against cellulose. It liberated more reducing sugars and caused more significant decomposition of fibres. The predominant effect of the endoglucanase E2 was a smoothing of the fibre surface. The cellobiohydrolase split a cellulose fibre into many short fibres.

Notes: The enzyme Glucoamylase [1,4-α-D-glucan-glucohydrolase EC 3.2.1.3] is very important for the food industry. It is used for producing glucose, ethanol and beer, as well as in technological processes that require the decomposition of starch. Eight mutants of the species Aspergillus niger are evaluated and tested with respect to their production of Glucoamylase and proved to be suitable. The task is to find the mutant showing the highest enzyme activity with a given precision. Conventionally, this kind of multiple decision problem is handled by the analysis of variance (Model I), which tests the homogeneity of the population means, but in this case the results do not supply the desired information. Provided that the enzyme activities of the mutants are different, selection procedures can be used to choose the mutant with the “best” or at least a “good” level of activity.In this paper, a short methodical summary about the two classes of selection procedures is given, i.e. the indifference zone (and d-correct) procedures and the subset procedures. By the example of the selection of a mutant with high enzyme activity the planning of experiments is shown. Depending on suppositions about the variances, different selection rules are applied. Starting with the subset procedure of GUPTA, the number of mutants is reduced to seven. The following application of the d-correct procedures of BECHHOFER, DUNNETT and SOBEL allow us to calculate the necessary sample size of n = 49. Then the mutant whose sample has the largest mean will be selected as a “good” one with a given precision of d = 4 [u/l] and a probability of correct selection of (1-β) = 0.9This application is result of a cooperation between the Dept. of Food of the Technical University, Berlin, and the Dept. of Biotechnology of the Higher Institute of Food and Flavour Industry, Plovdiv, sponsored by the DAAD andthe TU Berlin.

Notes: Three different kinds of biomass, namely Populus deltoides, Eupatorium adenophorum and sericulture waste were used individually for the cultivation of Pleurotus sajor-caju, alone and mixed with paddy straw. P. sajor-caju, when used alone, exhibited a very good colonizing ability on these substrates, except in sericulture waste. The biological efficiency of P. deltoides and E. adenophorum when used as pure substrate was 75 and 77%, respectively, but it increased to 102% when P. sajor-caju was cultivated in a mixture with paddy straw in a ratio of 1:2. Experiments examining the growth on sericulture waste in both pure and mixed substrate are encouraging. From the analysis of substrate before and after the cultivation of P. sajor-caju it was noted that subsstrates were enriched in their protein content as a result of growth of this mushroom. The percentage of degradation of cellulose, hemicellulose and lignin showed that P. sajor-caju is capable of utilizing all three major components. The fruit bodies of P. sajor-caju were analyzed for crude protein content, crude fat and carbohydrate content. The energy values in the fruit bodies of P. sajor-caju and different organic wastes were found to vary from 282 to 309 kcal/100 g and from 319 to 467 kcal/100 g, respectively. It was found, however, that the energy recovery from organic wastes by fruit bodies was very low, i.e. 4.19-8.73 kcal/100g of dry substrate.

Notes: The potential for the production of 1,4-piperazinium-(L, L)-dilactate from L(+)-lactic acid preparations obtained by fermentation was studied. Piperazinium dilactate was found to be a very suitable source material for poly(lactic acid) production. In a novel polymerization process, the intermediate dilactide was directly formed in the salt melt at a moderate temperature. High-performance cultivation of Lactobacillus paracasei on a glucose-MRS medium was carried out using high-viability inocula. After the cell mass had been removed from the fermentation broth by centrifugation and/or ultrafiltration, the lactic acid solution was concentrated to 45% [w/w] by a two-stage electrodialysis process. Two methods of preparing 1,4-piperazinium dilactate were developed: the first from the medium-concentrated lactic acid (45%) and the second from a highly-concentrated lactic acid (85%) obtained by evaporation from the first one. Because there were no physical data on 1,4-piperazinium-(L, L)-dilactate in specialized literature, the pure product was characterized according to its solubility characteristics, melting point and spectroscopic analysis.

Notes: A total of 65 yeast strains were screened for their ability to grow and ferment lactose in a standard DURHAM tube test at 30 °C. Based on the kinetic parameters for lactose and whey lactose fermentations in shake flask cultures, the strain Candida psedotropicalis 65 was chosen for further studies.Some of the cultural parameters affecting ethanolic fermentations on lactose were standardized. At an initial lactose concentration of 100-120 g/l in the medium containing concentrated whey or lactose, at 40 °C and within 48 h, the selected strain reached an ethanol concentration of 41-59 g/l, an ethanol productivity of 1.3-3.0 g/l/h, a lactose consumption of 99%, an ethanol yield 0.4-0.49 g/g and a biomass yield of 0.027 g/g.

Notes: High temperature extrusion cooking of rye was used as a pretreatment for ethanol fermentation, and yeasts and bacteria were compared for their fermentation rates. Extrusion cooking caused, on average, a 7.5% increase in ethanol yield in comparison to autoclaved samples. The best results were achieved for grain with a moisture of 21-23% which was extruded at temperatures of 160-180 °C.Extrusion decreased the relative viscosity of rye grain water extracts, so it was possible to mash it without α-amylase. The efficiency of fermentation of extruded rye without Termamyl was equal to that of autoclaved and traditionally mashed rye (using α-amylase).The rate of fermentation of extruded rye grain by Zymomonas was higher during the first stage, but the final ethanol yield was similar for the bacterium and the yeast.Though both microorganisms gave good quality distillates, the concentration of compounds other than ethanol achieved from extruded rye mashes, which were fermented by Z. mobilis, was five times lower than for yeasts.

Notes: An altered ploidy level was observed in plants regenerated by adventitious shoot formation from seedlings of Hypericum prformatum L. (2n = 4x = 32). Among the somaclones of the Ro generation, the presence of diploids (2n = 2x = 16), triraploids (2n = 3x = 24), tetraploids (2n = 4x = 32) and mixoploids was detected. Cytogenetic analyses of the R1 and R2 progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generation.While almost all the seed progeny of diploids (100% in R1 and 94% in R2) progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generations.While almost all the seed progeny of diploids (100% in R1 and 94% in R2) and more than 60% of tetraploids (61% in R1 and 73% in R2) retained their chromosome number, cytogenetic diversity was observed in the progeny of triploids, mixoploids and some tetraploids.Somaclones and their offspring were analyzed for hypericin content. Statistical evaluation showed a correlation between hypericin content and ploidy during a two-year cultivation of R0 somaclones and in their R1 and R2 progenies.

Notes: Urban waste waters were treated with pure ozone or combinations of ozone, hydrogen peroxide and/or UV radiation to study the course of resulting BOD (biological oxygen demand)-time profiles and to propose a kinetic model. BOD-time profiles of chemically treated waste waters show an initial lag period that first order kinetic models cannot describe. A second order kinetic model is then proposed that satisfactorily fits experimental BOD-time profiles, except when hydrogen peroxide has been used. In these cases, BOD-time profiles present the highest lag periods observed. By applying this model, three parameters are determined: the biokinetic constant (k) which is an index of the biological removal rate; the potential amount of biodegradable matter (BODT), and the measure of the size of inocula and microbial activities of microoganisms (λ). The model was checked with experimental results of BOD-time profiles corresponding to both untreated and chemically ozonated urban waste waters. Ozonated waste waters showed the highest values of k and BODT, which implies an improvement of waste water biodegradability after ozonation. However, values of λ corresponding to ozonated waste waters presented lower values than those of untreated waste waters. This was due to the lag period observed in the BOD-time profile, which was a consequence of a lack of microorganism acclimation to ozonated waste waters. The effect of the ozone does, pH and carbonates during ozonation on COD (chemical oxygen demand) and the above indicated parameters was also studied. There was an optimum ozone dose which was 138 mg/l for this specific system. This led to the highest biodegradable fraction (ϕ) and the highest biokinetic constant (39% increase in ϕ and 4.7- fold increase in the value of k, respectively, compared to untreated waste waters.). Another significant fact was that a higher COD reduction was observed in the absence of carbonate during ozonation at basic pH values. In addition, the percentage of variation in the biodegradable fraction (Δϕ) of ozonated waste water increased compared to the untreated waste water at acid pH. The results suggest that ozonolysis, the direct molecular ozone way of reaction, due to its selective character, increases the biodegradability of waste water more than other chemically advanced oxidation processes based on hydroxyl radical reactions.

Notes: Waste waters from olive oil processing may cause severe pollution in the Mediterranean area, since they have a high level of chemical oxygen demand (COD) (100-200 g/l) and contain other organic and inorganic compounds. In all olive oil producing countries, the reduction of pollution in olive oil mill waste waters at reasonable costs and using techniques suitable for most industrial applications is an unsolved problem.For this paper, the yeast Yarrowia lipolytica ATCC 20255 was grown on waste waters from an olive oil mill in a 3.5 1 fermenter under batch culture conditions.The results showed that the yeast was capable of reducing the COD value by 80% in 24 h. In this way, a useful biomass of 22.45 g/l as single cell protein (SCP) and enzyme lipase were produced.During this process, most of the organic and inorganic substances were consumed, only aromatic pollutants were still present in the fermentation effluents. Therefore, we used a phenol degrader, namely Pseudomonas putida, to reduce phenolic compounds in the fermentation effuents after removing Yarrowia lipolytica cells. P. putida was effective in reducing phenols in only 12 h.

Notes: Methylobacterium rhodesianum MB 126 was cultivated using extended cultures without outflow. The feeding regime was based on the pH-regulated synchronous dosages of ammonia, methanol, phosphatc and trace elements according to supposed stoichiometric relations. The acidity of the culture medium was kept constant at pH 6.8, whereas the dissolved oxygen concentration was adjusted at 80% of saturation by autoregulation of the stirrer speed. However, besides testing technical conditions, two types of fermentations were discovered which are described in this paper. Firstly, although at the beginning of the bioprocesses the impeller speed increased up to 2,000 rpm, a decrease of dissolved oxygen down to zero was unavoidable. Secondly, methanol was accumulated temporarily up to 44 g/l and 26 g/l at 23 h of fermentation time and without inhibition of growth at least up to 30 g/l or PHB production. During this accumulation of the carbon substrate, exponential growth phases were detected showing growth rates of μ = 0.20/h and 0.21/h. But then, phases of retarded growth followed, whereas the methanol disappeared either continuously or after a steady level. In the course of a 54-h fermentation period, the synthesized PHB amounted to a content of above 50% of cell dry mass. From this data, a volumetric productivity of 0.4 g PHB/lxh was estimated. Moreover, the growth related yield coefficients were calculated to YX/MeOH = 0.21 and YX/MeOH = 0.14, whereas the product related yield coefficients amounted to YPHB/MeOH = 0.12 and YPHB/MeOH = 0,09. Since the shift down of growth rates as well as the production of PHB agreed in time with partial oxygen limitation (40% oxygen saturation), the competition observed between the tricarboxylic acid cycle and PHB synthesis was discussed. Summarizing the results, it was concluded that the frequently described inhibitory effect of methanol of above 2 g/l seems to be rather an effect of experimentally chosen conditions than of a general physiological phenomenon. Therefore, it could be demonstrated that the toxicity of methanol could be overcome if it was not dosed at different times but simultaneously with other medium components.

Notes: Individual culture supernatants of six cellulolytic fungi and their mixed enzyme systems were compared in hydrolysis of pure celluloses and cellulose-rich wastes. It has been observed that the hydrolysis rate of pure cellulosie substances in general increased by mixed enzymes as compared to the enzymes supernatant derived from only one microbial source. This effect was particularly high when Trichoderma and Penicillium enzyme systems were operated together.

Notes: The study of a heat-shock process for RNA reduction was carried out for different yeast strains. Different results were obtained from each of them. Candida utilis NRRL Y-660 shows its best performance after a 8-s. heat-shock in the presence of 3% NaCl. For commercial baker's yeast Saccharomyces cerevisiae and Kluyveromyces fragilis L-1930, similar results were obtained with only 1% of NaCl. The latter needed longer heat-shock periods. e.g. 15s. to give such an RNA reduction. Biomass recovery ranged from 60 to 75%, being higher for C. utilis and K. fragilis while excessive losses were observed in S. cerevisiae cells.No significant protein deterioration was obtained in the best performance samples. The aminoacid profile appears to be improved in comparison to the starting material in these strains after RNA reduction.

Notes: Ethanol synthesis was initiated in aerobically pre-cultivated synchronized yeast populations by interrupting aeration and adding carbon substrate. Synchronization of yeast-cell functions was carried out by aerobic phased cultivation.Ethanol synthesis was more effective if it was closely connected with aerobic cell-mass synthesis and cell proliferation. Thus, anaerobic continuous ethanol production with cell recycling could be intensified by replacement of aged cells in single-cell state by aerobically pre-cultivated budding cells.

Notes: The strains E. coli C 600 and E. coli C 600 pL CR 665-58 were cultivated on a glucose containing nutrient medium. The cell states of the cell cycle were investigated by means of phased cultivation. The doubling time and the specific carbon-substrate consumption of cells were higher when E. coli C 600 pL CR 665-58 was used. During cell doubling cell states characterized by different specific carbon-substrate consumption coefficients were observed.By adaptation of carbon-substrates supply to the repetitive cell states during continuous cultivation of synchronized bacteria populations the efficiency of cell-mass production was increased by 15 percent.

Notes: Xanthan overproduction only takes place if a sugar which may serve as precursor is present and transition to limited growth occured. This transient phase is characterized by a change in composition of macromolecular cell components (RNA, protein, carbohydrates). During the transient phase nearly no nitrogen is consumed, whereas glucose and oxygen consumption proceeds nearly undisturbed. The changes observed in the transient phase are discussed in context with physiological adaption.

Notes: The influence of the osmotic pressure on the viability of yeast cells was studied in batch processes. It could be found, that the viability is a function of the total osmotic pressure obtained by adding the partial osmotic values of the principal ingredients saccharose, ethanol and salts dissolved in the medium. At optimum process conditions (pH, T, etc.) the cells can tolerate the osmotic pressure up to fixed value π1. Above π1 the viability decreases linearly and upward of a second threshold value π2 nonlinearly. In the case of the used strain Saccharomyces cerevisiae Hansen Sc 5 the values of the both points are π1 = 25 atm and π2 = 47 atm.

Notes: Two methods were employed in order to concentrate a large volume of an extracellular enzyme mixture for lysis of yeast cell walls: ultra-short-time evaporation and ultrafiltration. In the case of ultra-short-time evaporation there was a loss of activity by temperature while by ultrafiltration a good concentration could be received.

Notes: No Abstarct.

Notes: Positive and negative effects of dilution of raw effluents from swine breeding are discussed, as to the treatability of those waste waters. Its effects on oxygen consumption and on the variation of inhibitory actions possibly observed, are studied and quantified. Using BRADENDER and VANDEPUTTE techniques based on peptone degradation, and determining PHELPS'S equation parameters for different consumption curves observed, the advantages of dilution versus treatment of raw effluents is studied.

Notes: Experimental kinetic data (initial rate and high conversion) on the hydrolysis of cellobiose by 1,4-β-glucosidace (Gliocladium sp.) have been analysed and a competitive inhibition by glucose has been proposed. The determination of kinetic parameters from integral data is based upon algorithms for non-linear optimization and numerical integration. The values of kinetic constants \documentclass{article}\pagestyle{empty}\begin{document}$(v_{\max } = 1.02\frac{{\mu {\rm M}_{{\rm glucose}} }}{{{\rm mg}_{{\rm protein}} \cdot \min }},K_M = 2.6{\rm mM/l, and }K_P = 1.2{\rm mM/l)}$\end{document} agree well with the initialrate results. An important distinction is the confidence limit of parameters. Linear regression analysis shows a virtual accuracy and can lead to wrong conclusions.

Notes: The accumulation of nucleic and protein (amino nitrogen) components as decomposition products of the process of autolysis of Saccharomyces cerevisiae yeast cells was studied at 50°C under the effect of various membranotropic additives. The influence of the added n-alcohols, n-fatty acids and several peptides was investigated in the range of concentration of 0.1-0.5 M. The maximal acceleration of the autolysis has been demonstrated under the effect of additives with a hydrophobicity of 7.5-8.5 ccal/M. In all the investigated concentrations stearic acid and octadecyl alcohol have an inhibitory influence. The role of the hydrophobic influences and the mechanism of autolysis are discussed.

Notes: The effect of different quantities and kinds of vegetable and animal oils and the importance of the time of the oil addition on growth and protease synthesis by T. vulgaris was investigated. The used oils stimulate the protease production if they are added in a suitable concentration. However, the stimulation effect of each oil is different. Culture inoculation with spores gives the best results, when oil was added to the medium 1 up to 2 hours after beginning of the fermentation. The enzyme activity is equal to or lower than the control, when the oil addition was carried out before or 3 hours after starting the fermentation.

Notes: By combined application of chemical pretreatments, capillary gas-chromatography and mass spectrometry it was possible to enlighten the structure of atypical fatty acids with hydroxy groups and cyclopropane rings under the use of only a few of reference substances.The direct alkaline saponification of the sample with liberation of fatty acids and following methylation with boron trifluoride/methanol or diazomethane was proved to be the best method regarding to precision and speed of the sample cleanup.

Notes: The splitting of vegetable and animal oils used as antifoam agents and the metabolization of fatty acids released were analysed during fermentation of T. vulgaris in a 30 l jar fermenter. During cultivation time of 22 hours the oil amount decreased by 60 to 70%. The metabolization of fatty acids is 50 to 90% of the starting level depending on the kind of acid. The eventual effect of the fatty acids released from antifoam oils on the protease production is discussed.

Notes: Lipid extract isolated from biomasses of Lodderomyces elongisporus IMET H 128 grown on gas oil 7(B.p. 240-380°C) and fractions of the lipid extract (acetone soluble and fatty acid fractions) reduced the concentration of potato virus X in inoculated as well as in secondarily infected leaves markedly. The antiphytoviral inactive phosphatide fraction was converted into a fraction with high activity by partial hydrolysis with SO2 as acting agent.

Notes: This paper presents the application of a new developed measuring device for continuous determination of ammonium concentration especially in the field of biotechnology. Kinetic measurements of changes of ammonium concentration during stationary and instationary growth of microorganisms allows to quantify such interesting parameters as nitrogen consumption rate rN, productivity rx, specific growth rate ß, adaption time, diauxic behavior and mass content MF of fermenter etc.The results received by the combination of appropriated methods with the ammonium measuring device are not limited to biotechnology, so other applications in the field of chemistry, agriculture, technology, waste water industry etc. are possible.

Notes: The influence of ethanol and acetic acid concentration on the ATP-pool and energy charge of Acetobacter rancens was investigated.The behaviour of growth and ATP-pool is contrary one to each other. An increasing concentration of acetic acid results in decreased growth rate, ATP-pool and energy charge.

Notes: An analytical method for a rapid determination of the protein dissolved from microorganisms after cell disintegration and protein extraction is presented, thereby distinguishing both the isoelectrical precipitable and the isoelectrical nonprecipitable protein fraction. The method is especially usefull for controlling disintegration and protein extraction steps in production of protein isolates from microbial biomasses.

Notes: The primary objectives in biological wastewater and sludge treatment processes are to procedure a minimum quantity of solid, stable residues and a maximum quantity of carbon dioxide from the organisms present in the process feeds. As far as minimizing solids production in activated sludge type processes is concerned, endogenous activity in the recycled biomass is usually considered to be the most important mechanism. However, increased understanding of the growth characteristics of mixed microbial cultures suggests that lysis and “cryptic” growth are probably dominant mechanisms. For pathogen destruction in treatment processes, death and subsequent lysis of pathogens are clearly events that must be promoted.Here, the kinetics for death, lysis and “cryptic” growth in aerobic wastewater treatment and aerobic sludge stabilization processes are examined.

Notes: The term “autolysis” was introduced into biological literature by SALKOVSKY [1]. Ever since it began to be used to designate self-digestion of cells under the action of their own intracellular enzymes. This definition is sufficiently satisfactory with regard to bacteria, and there are published lots of original and review papers dealing specifically with bacteria. Considerably less material has been accumulated on eukaryotes, apparently due to the absence of the fact of the cell self-digestion in most yeasts.

Notes: The total amount of carbon dioxide (CD) produced by a microbial culture is evolved via an outlet gas stream, outflowing broth, and can lead to a rise of the CD content in broth. To analyze relations among the three amounts, the equilibrium is considered between different ionic forms of carbon dioxide at different pH values as well as between the gaseous and disolved CO2. Dependences of the equilibrium constants on temperature are found by a thermodynamic analysis. Numerical estimation of an error of the CD production rate measurement, originating from the neglect of dissolved CD, is developed. The gas analysis technique alone provides a sufficient accuracy at pH lower than 6. At higher pH the error can be estimated using equations presented below.

Notes: At the investigation of some properties of the α-amylase and proteinase in the culture filtrat from Bacillus licheniformis MB 80 strain it has been established that the α-amylase activity is the highest at pH 6.0 to 6.5 and at 90°C, that the proteolytic activity is the highest at pH 9.5 to 10.0 and at 70°C and that the proteinase is inactivated at temperatures over 70°C.

Notes: A hydrocarbon utilizing strain of Arthrobacter globiformis Lb isolated from local soil has been found to yield lysine 3.4 g l-1, keeping the medium optimal for pH, C- and N-sources. Addition of antibiotics and micronutrients to that optimal media stimulated cell growth and enhanced lysine yield.

Notes: It has been demonstrated that strains of Bordetella pertussis used for vaccine production contain temperate phages. It can be conducted from many experiments performed in our laboratory. that 10-100 phages per 1010 bacteria are released. However, the production of bacterial mass is not markedly influenced by lysogeny.Strains of Bordetella bronchiseptica used for production of vaccine against Rhinitis atrophicans of pigs have temperate phages too. These phages may cause a complete lysis during a submerse cultivation.The phages of Bordetella pertussis and Bordetella bronchiseptica can be propagted on Bordetella parapertussis.

Notes: The effects of pyrccarbonic acid diethyl ester (PADE) on Lactobacillus casei Sl and its phage Jl was investigated in relation to the control of phages in the dairy industry and other technica fermentation processes.PADE exhibited a bacteriostatic effect at 0.5 to 8 mM and a bactericidal effect at 10 mM or higher. It inhibited the growth of the phage at its bacteriostatic and bactericidal concentrations. The growth inhibition of the phage was reversible at the bacteriostatic concentrations but complete and irreversible at the bactericidal concentrations. PADE inactivated the free phage within several minutes; 10 and 30 mM of PADE inactivated 90 and 100%, respectively, of the phage. It completely decomposed into ineffective components in several minutes. The bacteria grew almost normally when they were inoculated after the complete decomposition of PADE.These four characteristics of PADE - its bactericidal effect, its inhibitory effect on phage growth, its phage-inactivating effect and its decomposition - suggest a novel strategy for phage control in technical fermentation processes, including the dairy industry.

Notes: Alcaligenes latus strain DSM 1123 has been tested for the production of Poly-D(-3)-3-hydroxybutyric acid using sucrose as the only carton source. The strain is capable of accumulating the polymer associated to the growth very fast and lup to high concentrations in the biomass. Alcaligenes lotus seems to be very interesting for the production of Poly-D(-)-3-hydroxybutyrate in a cheaper and easier way as with other organisms discussed for the biotechnological process in the past.

Notes: Although the carbon/energy ratios of heterotrophic substrates for microbial growth are different this is not reflected in biomass. Nevertheless the macromolecular composition of cells may vary in dependence on growth conditions this does hardly influence the elementary composition and the growth yield. The energy requirement for synthesis of biomass starting from a central precursor, e.g. phosphoglycerate, can be assumed to be constant, hence any differences in carbon conversion efficiency must be attributed to carbon catabolism up to this precursor. This sequence determines if and to what extent an auxiliary substrate effect is possible. However, one has also to consider changes of the P/O ratio due to simultaneous utilization of substratesd which may account for the increase in growth yield with Hansenula polymorpha growing on a methanol/glucose mixture.

Notes: The effect of dehydration on proteolysis and activity of proteases A, B and C in the cells of baker's yeast Saccharomyces cerevisiae was investigated. It can be concluded, that under investigated conditions of yeast Saccharomyces cerevisiae drying a decrease of proteases activity takes place. In cells a limited proteolysis takes place which is indicated by an increase in amino nitrogen content and a decrease of tryptophane synthase activity. Adding the protease inhibitor to yeast suspension prevents decrease of tryptophane synthase activity upon dehydration.

Notes: Autohydrolysis was studied as a pretreatment to enhance sugar yields from enzymatic hydrolysis of wheat and rape straw, beech, birch and poplar sawdust. Reaction temperatures were 185°C to 212°C and the reaction time 20 min. The pretreated slurries were hydrolyzed with “Novo” cellulase and Fusarium sp. 27 cellulase at 45°C and pH 4.8 for 24 h with addition of Fusarium sp. 27 cellbound cellobiase. From 85% to 90% sugar content of substrates were converted to reducing sugars after 24 h enzymatic hydrolysis, with exception of poplar wood.10.8 g biomass was obtained after cultivation of Fusarium sp. 27 with water solution hemicellulose fraction from 100 g beech sawdust autohydrolyzed at 200°C during 20 min.