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: The ability of utilization of vegetal oils belongs to common properties of Streptomycetes. During the cultivation of Streptomyces rimosus and biosynthesis of oxytetracycline in 15 m3 fermenters, a fixed regime of soya bean oil feeds as antifoam agent and partial carbon source according to subjectively designed mechanism was investigated and further also feeding regime after exhausting starch as main carbon source and finally his dosing with ammonia sulphate in accordance with physiological activity of the culture. In the second case with semicontinuous supplements of soya bean oil it was possible to prevent premature autolysis of mycelia and to extend the biosynthetic process with keeping the oxytetracycline production rate. The third approach, the most progressive one, represents besides the automatisation of control loop the necessity of assurance continuous pH adjustment for elevation of the process production rate.

Notes: The biosynthesis of cellulases and xylanase by the mould strain Trichoderma sp. M7 on submerged and solid-state cultivation conditions has been studied. The effect of different inducers on the enzyme biosynthesis on the conditions used was determined. The relation between the enzyme biosynthesis and the morphological state of the producing strain was studied. The advantages of the submerged cultivation conditions with regards to the efficiency of the enzyme inducer are shown.

Notes: The investigations demonstrate that in addition to Saccharomyces also strains Candida and Hansenula can be used for ethanol production. Their efficiences are at the standard level and the first phase of fermentation is considerably accelerated with results in suppression of bacterial contamination in cold mashing. In the future efficiency optimisations will be expected based on mixed strain populations as well as on technological improvement. Furthermore, genetic modifications present actually a real prospect to secure “made-to-measure” strains for special processes of corn mash fermentation.

Notes: A comparative response of specific trace elements and organic growth factors for the growth of five Hansenula species (H. anomala, H. beijerinckii, H. ciferrii, H. polymorpha and H. sydowiorum) has been studied. Out of twenty three trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth of all yeast species studied here, whereas the rest of the elements exhibited variable essentiality. From fifteen organic growth factors tested, thiamine, biotin, pyridoxine and inositol are the most commonly required growth factors by the yeasts, whereas the rest of the organic growth factors showed variable essentiality. All species of yeasts investigated required different concentrations of trace elements and organic growth factors for their optimum growth. Concentrations higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied.

Notes: By using tailor-made capillary columns the changes of the free fatty acid spectrum during anaerobic putrefaction of piggery waste and sludge at pH 5.0-5.5 were examined. Free fatty acids with 18 to 22 carbon atoms were the main components before putrefaction. With progressive fermentation time the share of short chain acids formed from higher acids was increased.

Notes: The establishment of an on- or off-line-optimal-controlled fermentation process requires a system of situation identification  -  process rearrangement. The choice of the structure and the mathematical model of the situation is difficult. To characterize the situation it is necessary to determine the process-specific vector which regards the major features of the processes. The determination of the structur and the vector which regards the major features of the fermentation process has been demonstrated by several examples.

Notes: In the fodder yeast production from sulfite spent liquor (SSL) the content of yeast-poisons in the SSL is of particular importance. The negative influence of sulfur dioxide has been known for a long time.Furfural is also named as a pollutant. Our own works showed that there is only an influence on the RS-analysis and in this way a decrease of yield is simulated but not genuine.Practical results and theoretical calculations showed that 1.0 gram of furfural is equivalent to 1.88 g RS.This knowledge is of importance for carrying out the production process by simultaneous change of the furfural concentration. In this way the charge of the fermenter with carbohydrate can be too high or too low.

Notes: The article summarizes the work of this laboratory on the design of eleven types of amperometricpenzyme electrodes mainly based on the CLARK oxygen sensor in connection with cross-linked oxidases. Special attention is paid to the sensors coupled with plant tissue slice for determining L-ascorbic acid and phenols. A “second generation” bienzyme electrode is reported which enables tow analytes forming a metabolic couple to be determined simultaneously. A principle of the first useful model of conductimetric enzyme electrode for assaying urea and arginase is also presented.

Notes: Kluyveromyces bulgaricus cells were immobilized in matrices resisting to complexing anions. Yeast entrapped in alginate stabilized by polyethylenimine and glutaraldehyde were unable to hydrolyse whey owing to the inactivation of β-galactosidase by the stabilizing agents. Chitosan was resistant to whey medium but decreased the yeast hydrolyzing capacity by 15% with respect to alginate. The hydrolysis rate was found to be unchanged for 37 days at 21-25°C.

Notes: The paper offers a survey of theoretical concepts for the analysis of metabolic systems in open connditions such as realized in cultures of microbial cells. The dynamics and regulation of metabolism within the cell is condensed into a block description of the system to which global performance and design criteria are applied.

Notes: A method is introduced which makes a continuous oxidation of glucose to glucose acid possible. This method is based on the auxiliary-substrate concept and co-metabolism, respectively. Micro-organisms (e.g. Acinetobacter calcoaceticus), which cannot assimilate glucose, but merely oxidize it, are grown continuously on a heterotrophic substrate (e.g. acetate). While growing they simultaneously synthesize gluconic acid. The productivity of the gluconic acid synthesis with a given strain depends on the dilution rate and the mixing proportion.Since growth and product synthesis are closely connected and growth yield is very much higher due to an auxiliary substrate effect in the presence of glucose than on the heterotrophic substrate alone, this method is suitable for SCP production as well. The productivity of gluconic acid production is controlled at a certain dilution rate by the mixing proportion of the growth substrate and glucose.

Notes: A process for biological removal of iron from quartz sands, kaolins and clays was developed in which these industrial minerals were leached at 90°C with lixiviant produced as a result of the cultivation of acid-producing heterotrophic microorganisms, mainly strains of Aspergillus niger, at 30°C in a nutrient medium containing molasses as a source of carbon and energy. The lixiviant, i.e. the fermentation fluid, contained oxalic and citric acids as main components and after the cultivation was acidified to a pH of 0.5 by means of hydrochloric acid. The leaching was carried out in mechanically stirred acid-resistant vats for a period of from 1 to 5 hours. The iron content of some sands treated by this method was lowered from 0.035-0.088 to below 0.012% Fe2O3 making them suitable for the preparation of high quality glass. The iron content of different kaolins was lowered from 0.65-1.49 to 0.44-0.75% Fe2O3 and as a result of this their whiteness was increased from 55-87 to 86-92%. The iron content of a clay was lowered from 6.25 to 1.85% Fe2O3 and this increased the fireproofness of the clay from 1 670 to 1 750°C. Similar process was used for leaching of aluminium from aluminosilicates, mainly clays and kaolins. However, after the cultivation the fermentation fluid was acidified either by means of sulfuric or hydrochloric acid or by means of different mixtures of inorganic acids. For enhancing aluminium solubilization the aluminosilicates were heated before leaching at 600-650°C for 1-2 hours. Over 90% of the aluminium present in different clays and kaolins was leached within 3-6 hours in this way.“Silicate” bacteria related to the species Bacillus circulans and B. mucilaginosus were used to leach silicon from low-grade bauxite ores containing aluminosilicates as impurities. The bacterial action was connected with the formation of mucilaginous capsules consisting of expolysaccharides. The solid residues after leaching were characterized by higher values of alumina content and were suitable for processing by means of the BAYERprocess for recovering aluminium.Heterotrophic bacteria were used to leach manganese from oxide ores using different organic compounds as reducing agents.

Notes: The object of the presented studies was to determine the conditions of protein biosynthesis from lignocellulosic raw material using filamentous fungi.It was found that on beet pulp + 50% wheat straw, strain A. niger (A.n./61) shows the highest effectivity of protein biosynthesis. Using this strain, after 48-hour incubation the following results were obtained: increase in protein 4.43 g/100 g·DM, daily protein increase coeffizient 2.22 g/100 g DM x 24 h, protein yield (based on the decrease in dry matter) 22.3% and cellulose utilization 37%.Upon use of a new strain CEL 2 and milled wheat straw as the substrate, the best results obtained after 74-hour incubation were as follows: increase in protein 1.82 g/100 g DM, daily protein increase coefficient 0.61 g/100 g DM x 24 h, protein yield 15,8% and cellulose utilization 22.0%.For rape straw and strain Sporotrichum pulverulentum, after 192-hour cultivation the following results were obtained: increase in protein 5.4 g/100 g DM, daily protein increase coefficient 0.68 g/100 g DM x 24 h, protein yield 14% and cellulose utilization 50.2%.

Notes: The influence of long-term storage on the stability of the cellulolytic enzyme and protein biosynthesis ability, was determined.Microorganisms belonging to genera Aspergillus, Fusarium, Penicillium, Sporotrichum, Allescheria and Mucor were used. The strains were stored on wort agar slants, on SAUNDER'Smedium and on a medium according to MANDELS-WEBER, under paraffin oil or without it. After 3 years storage no influence of the storage method on the biosynthesis of cellulolytic enzymes (strain A. niger 33/2 and 33/20) was found. A systematic increase in the celluloslytic activity was exhibited by strains A.n. 33/2 and A.n. 33/20 on wort agar (40 and 98%, respectively) and on SAUNDER'Smedium (79 and 66%, respectively), as well as by the new strain CEL 2 on Saunder's medium without paraffin oil.

Notes: NO ABSTRACT.

Notes: By the example of the Penicillin G production, it is shown, how the production process can be improved by using pellet suspension instead of highly viscous filamentous mycel. In order to optimize the pellet geometry, dissolved oxygen concentration profiles were measured, and the overall mass transfer resistance was calculated in the pellets; histological investigations were carried out with pellets also. All measurements indicated that the optimal pellet diameter is 400 μm. When using this pellet, the specific power input was reduced from 4-5 kW/m3 to 0.8 kW/m3. The losses during the recovery of Penicillin G can be reduced below 1% by using reactive extraction. The thermodynamics, kinetics and reaction technique of reactive extraction of Penicillin G are also taken into account.

Notes: Strains of Cellulomonas isolated from enrichment cultures with cellulose powder were cultivated with hempstalk wastes as the sole carbon source in a mineral medium. The yields of protein were not significantly different using the crude or alkali pretreated substrate in flasks experiments. Up to 12.5% protein was obtained on the untreated substrate with the best strain cultivated in a small fermenter.

Notes: An attempt is made to give a thermodynamic interpretation of the complete temperature profile curve of ethanol formation. Taking into consideration an enhancing competition between thermal activation and thermal deactivation of ethanol formation at increasing temperatures and supposing that the ethanol production is affected by a reversible and an irreversible term of thermal deactivation of a modified ARRHENIUS equation being current for the total biokinetic sphere may be derived: \documentclass{article}\pagestyle{empty}\begin{document}$$\ln {\rm (}v_2 /v_1 ) = - \frac{1}{R}(\Delta H_{{\rm EtoH}}^A - \Delta H_T^{D_1 } - \Delta H_T^{D_2 } )\left( {\frac{1}{{T_2 }} - \frac{1}{{T_1 }}} \right) \cdot $$\end{document}.The quantities ΔHTD1 and ΔHD2T are identical with the temperature functions of the change of entropy caused by reversible and irreversible deactivation of ethanol formation, respectively. Accordingly for the yeast strain Saccharomyces cerevisiae Sc 5 the calculated entropy coefficients of reversible and irreversible thermal deactivation of ethanol formation amount to CSTD1 = (0.245± 0.013) kJ/mol · deg.2 and CSTD2 = (1.657 ± 0.046) kJ/mol · deg.2.

Notes: To enhance the digestibility of wheat straw as an animal feedstock a partial delignification by action of 1percnt; aqueous alkali in combination with mechanical pre- and after-treatment steps is proposed. On the basis of in vitro digestibility by cellulase the influence of various process parameters on the effect obtained is summarized. Sheep feeding studies comparing original and chemomechanically pretreated straw confirm the suitability of the process-principle proposed for upgrading cereal straw. The practical feasibility of the process is considered with regard to animal nutrition and technology.

Notes: Employing anionic and non-ionic cellulose ethers, differing in type of substituent and degree of substitution, as substrates, the pH-profile of enzyme activity and the parameter Km and Vmax of the MICHAELIS-MENTEN kinetics have been determined with Penicillium citrioviride cellulase in an homogeneous system. Within rather wide limits, a linear correlation was found between the DS of the substrate and Km or Vmax, respectively. Also the pH-profile was found to depend on DS mainly, being bimodal at higher DS. On the other hand, no significant difference was observed between anionic and non-ionic cellulose ethers of about the same DS with regard to the parameters determined. It is assumed, that substrate-enzyme interaction is governed mainly by the length of non-derivatized chain sequences mainly and not by Coulomb interactions.

Notes: The microprocessor complex “Biotron-M” designed for automation of experiments in microorganisms cultivation carried out simultaneously on no more than 3 fermenters is described. The complex is based on KTS LIUS-2 and microcomputer “Elektronika-60”.Information and control functions as well as the complete system are considered. The operating system “Rafos” with double-task monitor is used as the system software. Special software is represented by a set of program modules performing the functions of the complex.An example is given concerning the operation of “Biotron-M” together with fermentation plant “FU-8”.

Notes: A hybrid computer completes a scale up line to a computer coupled fermentation (CCF) system for data processing, monitoring and operator servicing, documentation and process control. Presented experiences using this arrangement were adapted and transferred to microcomputer systems.

Notes: Some original observations have been made on the process of cassava fermentation to produce “foofoo”, a local nigerian diet. During the period of fermentation the pH of the fermenting liquor decreases from 6.1 to 3.4 at the end of the 6th day. The change in pH is uniform throughout the fermentation period. Decreases in dry weight of the fermenting cassava have been recorded; there is a very rapid decline during the third and fourth days of fermentation. Free reducing sugars decrease drastically within the first and second days. Total sugar concentration which is an indication of the starch content of the cassava also declines with fermentation time, and more so during the third and fourth days. Protein concentration in the liquor increases very rapidly during the first and second days of fermentation. It is believed that cassava protein is converted to microbial protein.

Notes: The specific growth rate of the ethanol producing bacterium Zymomonas mobilis was lower in the presence of oxygen than under anaerobic conditions. Aerobically, considerable amounts of acetaldehyde and acetic acid were formed in addition to the normal fermentation products, ethanol and carbon dioxide. This bacterium contains considerable amounts of pentacyclic triterpenoids, mainly 1, 2, 3, 4-tetrahydroxypentane-29-hopane. It seems that stability and permeability of the cytoplasmic membrane of this rather ethanol tolerant organism is achieved by the hopanoid content. A continuous culture of Zymomonas mobilis produced 60 g/l ethanol over a test period of 39 days. This strain was used for ethanol production from an enzymatically hydrolyzed wheat starch fraction on an industrial scale of 100 m3.

Notes: Microorganisms are able to interact with metal ions in aqueous solutions and to accumulate considerable amounts of them.The mechanism of the accumulation depends on the physiological state of the cells. In the case of resting cells the binding reaction takes place on the surface of the cell wall as a sorption process. The kinetic of the sorption processes in dependence of the physiological state of the cells, the concentration of Hg2+ and Cd2+-ions on the solution and the pH and temperature has been investigated.Beyond that possibilities for the desorption of the metals from the biomass have been tested.

Notes: The wild strain Aspergillus niger VKMF-2092 forms β-glucosidase on the basis of glucose as the sole carbon source. The formation of β-glucosidase is initiated after the glucose concentration in the medium has reached a low level since the formation is subjected to catabolite repression. The β-glucosidase is mainly cell-bound and only released after a longer period. Under non-repressed conditions the total formation of β-glucosidase is not associated with growth.By supplying glucose in a fed-batch-technique, maintaining a low actual glucose concentration in the medium, the formation of β-glucosidase is enhanced in comparison to simple batch fermentation. Using a fed-batch-technique with a frequently intermittent addition of glucose it is possible to increase the formation of β-glucosidase with regard to both productivity and the activity related to the mycelium and the fermentation broth as well. The increase of productivity is about two to four times greater than at constant feed rate of the same overall amount of glucose.The reason for this increase will be discussed below. A method is presented which permits to investigate the influence of the substrate concentration and other parameters on the enzyme formation in short periods of one and the same fermentation run.

Notes: The probable effect of increasing levels of ammonium nitrogen on the growth, efficiency of nitrogen fixation, and main cellular constituents of Azotobacter vinelandii was studied under shaking and static culture conditions.The presence of NH4+-N up to 50 mgl-1 level has no harmful effect on the multiplication as well as the yield efficiency ratio of the tested organism. A. vinelandii was able to fix dinitrogen in the presence of NH4+-N when both nitrogen sources were available in the culturing medium. The efficiency of nitrogen fixation was affected by the initial presence of NH4+-N in the medium, it was quite low at the highest level. The crude protein efficiency ratio was correlated inversely with the initial NH4+-N concentration, whereas the total carbohydrate efficiency ratio as well as the total lipid efficiency ratio were positively correlated with the NH4+-N concentration. The presence of NH4+-N in the culturing medium has no essential influence on the qualitative composition of the amino acids in the Azotobacter cells.