bluuebunny/crossref_metadata_2025 huggingface dataset:
Spezielle Anwendungsmöglichkeiten mikrobieller Proteasen
Authors: Heitmann P. , Meyer D.
Published: December 2004

A brief review of the most important properties and fields of application of microbial proteinases are presented. Special possibilities of an industrial utilization of these enzymes are discussed: in the photographic industry for the production and degradation of gelatin as well as for silverless photography, in the food industry for the improvement of the functional properties of proteins as well as for increasing their nutritive value, in organic synthesis for the production of peptides, and in sewage treatment plants for the stabilization of sludge.
Enzym‐Muster Methanol assimilierender Hefen in Abhängigkeit vom Kohlenstoff‐Substrat
Authors: Müller R. , Hofmann K. H. , Babel W.
Published: December 2004

The influence of the carbon substrates glucose and methanol on enzyme activities of the yeast Candida methylica was investigated by substrate‐shift experiments in discontinuous cultivation. Growth on glucose results in a repression of the enzymes necessary for methanol utilization. After depletion of glucose or addition of methanol these enzymes are derepressed or induced, respectively. Changes in the activity of enzymes of the intermediary metabolism turn out differently both in intensity and direction as a result of substrate‐shifts. The results suggest a basic change in the metabolism by growing Candida methylica in glucose or methanol.
Status and developments of animal cell technology using suspension culture techniques
Authors: Katinger H. W. D. , Scheirer W.
Published: December 2004

In this review the state of the art in animal cell technology, using suspension culture techniques is updated as far as the end of 1980. We have tried to discuss, on a broad basis, the current status and potential developments of both, the purely biological and the biochemical engineering aspects which may be important to improve the performance and design of animal cell technologies. The process economics could be considerably improved by the use of transformed animal cell substrates, the use of cheaper cultivation media and by methodological and engineering means. Most of these aspects are in the state of realization. Nevertheless, for a great variety of biological active substances which do not require so – or posttranslational processing, recombinant DNA‐techniques (e.g. genetic engineering) are a promising alternative for the production of animal cell derived substances.
Some aspects of fermentation as an unit process in chemical engineering
Authors: Mueller F. G.
Published: December 2004

There are described possibilities of scale up in stirred tank fermenters being based on known relations of mass‐, energy‐and heat transfer. The represented mathematical description shows the problems of the necessary scale up in the practice with the theory of similarity in the stirred tank fermenter. Relating on the method of RUSHTON for calculation of the energy capacity in different stirred fermenters the influence of the aeration is examined and confirmed with experimental results of the author. By the sysem of equations the known parameters of the aerobic fermenters can be calculated.
Effektivität von Modellierung und Optimierung mikrobieller Prozesse
Authors: Prause M. , Soyez K.
Published: December 2004

The aim of the technological treatment of microbial processes is the optimal working of the production plant. The treatment itself is to be seen as a process whose realization requires a certain amount of expenditure. The problem of optimization of this process can with certain restictions be approximately solved in a series of steps. After a general formulation of the problem explanations are given for two important and typical steps – the determination of the extend of modelling and the choice of production cultures.
Regulation of lysine biosynthesis in Brevibacterium flavum
Authors: Leite M. P. , Rukliša M. P. , Viesturs U. E. , Švinka J. E.
Published: December 2004

L‐lysine synthesis pathway enzyme activities: β‐aspartate kinase (EC.2.7.2.4), diaminopimelate decarboxylase (EC.4.1.1.20) for two L‐lysine producing strains Brevibacterium flavum 22LD and RC‐115 were studied. It has been found that β‐aspartate kinase and diaminopimelate decarboxylase in the Br. flavum RC‐115 are less sensitive to feed‐back inhibition by lysine and threonine. It is supposed that desensitized β‐aspartate kinase in the Br. flavum RC‐115 can be determined by genetical changes of the regulatory properties of the β‐aspartate kinase.

Auxotrophity in the locus of homoserine dehydrogenase was tested and no homoserine dehydrogenase (EC.1.1.1.3) activity was found in either strain.

The combination of these both types of mutation supplemented by the lack of catabolic repression in the RC‐115 strain makes it an active lysine producer in the medium with high carbohydrates content.
Gewinnung und Charakterisierung von Prolidase aus, Escherichia coli B., I. Gewinnung des Enzyms
Authors: Friese E. , Ruttloff H.
Published: December 2004

An enzyme being able to hydrolize the imido linkage at the N‐terminal end of proline is isolated from E. coli B. This fact corresponds to the specifity of hydrolization of the animal prolidase. Enzyme synthesis within the cells of E. coli B is carried out independently from growth. Changed environmental factors may influence the formation rate of enzyme in a restricted way. A relatively high enzyme biosynthesis can be reached by cultivating the strain E. coli B at a temperature of 37°C as well as an initial pH‐value of the medium of 7.0 in submerged culture (400–500 rpm) By variation of the medium composition enzyme synthesis does not change considerably, however, biomass yield can be increased about 100% If mechanical cell desintegration is optimized by means of ultrasonic or vibration homogenisator the cell components may be easily released with a higher proline specific activity as animal prolidase.
Calorimetric Glucose Determination by Glucose Oxidase —Methylene Blue
Authors: Kirstein D. , Schilder L. , Kahrig E.
Published: December 2004

The reaction between glucose and methylene blue, catalyzed by glucose oxidase (GOD)was analysed calorimetrically.

The amount of heat produced under saturating methylene blue concentrations ( > 10−2 mol/1)was measured with glucose concentration and time as parameters (kinetic procedure) Kinetic constants (pseudo one substrate kinetics) were derived from the experimental data: KM(glucose)= 1.18 × 10−3 mol/l and Vmax = 0.085 J/mg GOD min (3.89 · 10−6 mol/mg GOD min)

Comparison of caloric with optical measurements gave an enthalpy of reaction of 22.52 kJ/mol. Considering the observed substrate inhibition, glucose determinations are possible up to glucose concentrations of 0.1 mol/l.
Untersuchungen zur chemischen Zusammensetzung der Lipidfraktion von Acinetobacter calcoaceticus
Authors: Müller H. , Voigt B.
Published: December 2004

Lipids were extracted from the cells of Acinetobacter calcoaceticus EB 10 C IMET B 395 grown on gas oil (Bp. 240–360 °C) with benzine/alcohol (80 : 20). The lipid‐hydrocarbon‐extract obtained by this extraction method was 18.4%. The extract was composed of hydrocarbons, waxes, phospholipids, fatty acids, glycerides, and ubiquinones. The main components among the lipids were waxes. The compositions of phospholipid, fatty acid, wax, and ubiquinone fractions were analysed.
Zur Kinetik der Nebenproduktbildung bei der Überproduktion von Citronensäure durch Saccharomycopsis lipolytica
Authors: Behrens U. , Schulze E. , Weissbrodt E. , Scheffel B.
Published: December 2004

After exhaustion of the N‐sources the yeast S.l. excretes citric and isocitric acid with high rates without interferring in the postlogarithmic phase the intracellular production of reserve materials like polysaccharides and especially lipids. The synthesis of citric acids and of reserve materials are therefore autonomically proceeding processes inside of the cells

With increasing lipid content the ergosterol content increases

The utilization of the ergosterol rich yeasts as valuable byproduct of the citric acid production is discussed.
Ein mikrorechnersystem für fermentationseinrichtungen
Authors: Albrecht Ch. , Ichter K. R
Published: December 2004

For several years now, we can notice efforts in increasing the efficiency of microbial processes by means of more intensive scientific investigation of such processes. Essential prerequisites to it are improved possibilities for process monitoring (available sensors) as well as facilities for realtime processing of process information. In this paper a microcomputer system is represented, which has been constructed on the base of computing needs for fermentation. The computing needs for fermentation experiments are outlined and the structure of the microcomputer is described. As an example it is illustrated what tasks can be solved by this microcomputer in coupled operation with a laboratory fermentor.
Beitrag zur Optimierung des mechanischen Aufschlusses von Hefezellen
Authors: Luther H. , Schuster E.
Published: December 2004

The influence of technological variables on the cell disintegration of yeast suspensions by means of a ball mill and a high pressure homogenizer has been studied by measuring the electrical conductivity. The rate constants and half‐life periods are calculated. Regarding the production of protein isolates, the stipulation of optimal disintegration conditions requires a compromise between a degree of disruption as high as possible and a low destruction of the cell walls.

By homogenizing, fragments of cell walls arise which are more uniform and better separable in comparison with the milling process. Therefore the mechanical breakage of yeast cells on a large scale should be carried out by the use of high pressure homogenizers.
Untersuchungen zum Anfangsstadium der enzymatischen Hydrolyse unterschiedlich vorbehandelter Linterscellulose
Authors: Philipp B. , Dan D. C. , Linow K.‐J , Polter E. , Schulz G.
Published: December 2004

Starting from cotton linters cellulose modified in physical structure type of lattice, degree of order, state of swelling by different pretreatments, and from culture filtrates of Gliocladium spec., the initial stage of enzymatic hydrolysis of cellulose has been investigated. Especially with substrates of high degradability a considerable effect of stirring on rate of formation of soluble products was found. For linerization of yield‐vs‐time‐curves (% residue resp. 7percnt; solubles as a criterion for yield), a 2‐parameatric first order rate law was found to be suitable within a limited time interval, values of k1 were higher and for the accessible part of the substrate were lower in the initial stage of hydrolysis than in the later one. The MICHAELIS‐MENTEN‐constant kM has been determined for substrates of different physical structure after different times of reaction. Data found for kM indicated a stronger dependence of kM on reaction time than on physical structure of the substrate under conditions applied.
Ethanol from Zymomonas, a bacterium
Authors: Zajic J. E. , Maddux N. L. , Jones L. P.
Published: December 2004

Thirteen isolates ofZymomonas were analyzed for their ability to tolerate increasing concentrations of glucose and ethanol. In medium containing 5.0% (v/v) ethanol, four isolates grew well in 15.0% (w/v) glucose. Six cultures tolerated at least 6,0% ethanol. Of all the isolates, 7 preferred glucose and 4 preferred sucrose as a sugar substrate. In a nutrient medium containing mineral salts and high concentrations of pantothenate and biotin ethanol production for 2 isolates was approximately 7.0%. Continuous stirring and growth factors were responsible for this increased ethanol production.
Einfluß der limitation des wachstums von hefen auf den oxidativen stoffwechsel und die produktsynthese
Authors: Lozinov A. B. , Finogenova T. V.
Published: December 2004

The growth limitation of aerobic yeast cultures in the majority of cases involves a deep conversion of the metabolism and high changes in the functional state of the cells

The excretion of metabolits as one of this changes of great importance and the other variations in the state of the cells are the consequence of functional alternations of several anabolic and catabolic processes.
Entwicklung von Berechnungsmodellen für Enzymreaktoren (Teil 1)
Authors: Setzermann U. , Vondran J. , Mohr K.‐H.
Published: December 2004

It has been developed a model for a continuous working enzyme‐reactor to determine the deviation of temperature and concentration in axial and radial direction. It's based on Partial Differential Equations for mass and enthalpy transfer. The model regards the specialities of kinetics of enzyme‐catalytic processes with respect to the reaction rate. A difference method had been choosen which provided applicable results with respect to characteristic quantities of the substance under corresponding initial and boundary conditions. Some pictures show the deviation of temperature and concentration.
A desk‐top computer coupled fermentation system for the study of microbial processes: Description and some applications
Authors: Hampel W. , Woehrer W. , Bach H. P. , Roehr M.
Published: December 2004

The configuration and hardware components of a desk‐top computer coupled system for bench‐top bioreactors are described. Examples of on‐line acquisition of several directly accessible environmental process parameters and computations of directly inaccessible state variables are presented. The system described offers great advantages in experiments for establishing sophisticated control algorithms and for studying the physiological behaviour of microbial populations.
The technological possibilities for measuring of physiological population state features in fermentation practice
Authors: Schmidt A.
Published: December 2004

The known measuring methods for marking the physiological microbial population state are classified and evaluated. From this point the theoretical, measuring and control developmental stage is considered.
Ein Laborkleinfermentorsystem für die biotechnologische Grundlagenforschungl—MTA‐Ausrüstung
Authors: Iske U. , Rost H.‐J. , Portius S.
Published: December 2004

Laborfermentoren stellen ein grundlegendes Arbeitsmittel in der biotechnologischen Forschung dar, dessen Entwicklungsst and in entscheidendem Maße Leistungsfähigkeit und Effektivität der Forschungsprozesse bestimmt. Deshalb ist eng verbunden mit den stündig steigenden Anforderungen an Quantität und Qualität der Informationen aus den verschiedenen hierarchischen Niveaus biotechnologischer Prozesse die Entwicklung hoch instrumentierter leistungsfähiger Laborfermentorsyteme.

Der Trend, biotechnologische Prozesse in ihrer Raum‐Zeit‐Ausbeute traditionellen chemischen Prozessen anzugleichen, führte zur Entwicklung von Fermentorsystemen mit neuen Wirkprinzipien zur Gewährleistung hoher Stoffäbertragungsleistungen. Mit der Realisierung derartiger Hochleistungsfermentoren in großtechnischen Dimensionen ist verbunden die Forderung nach leistungsfähigen Laborfermentoren für die Erarbeitung wissenschaftlicher Grundlagen als Basis für eine gesicherte Maßestabsäbertragung.

Die Entwicklung eines 2,5 l Laborsterilfermentors mit hohen Stoffübertragungsleistungen stellt einen Beitrag zur Vervollständigung der gerätetechnischen Basis für die biotechnologische Grundlagenforschung dar.
Solid‐state (solid‐substrate) food/beverage fermentations involving fungi
Authors: Steinkraus K. H.
Published: December 2004

“Solid‐substrate” fermentation developed in the Orient is a very useful fermentation method. It is presently used to produce a variety of foods, beverages and related products. Solid‐substrate fermentation products utilizing fungi including soy sauce, miso and tempe, ontjom, sake, and bread have been produced for centuries at the home and village level. They are examples of economical methods of preserving and improving the flavor, texture and nutritive values of cereal/legume substrates. “Solid‐substrate” fermentation is also applied to animal products such as milk to produce Roquefort and Camembert cheeses which diversify the food flavors available to man

“Solid‐substrate”fermentation has certain advantages. The substrate is concentrated; the product can be extracted with relatively small quantities of solvent; the product can be easily dehydrated; moisture level can be controlled favoring the desired organisms; enzyme concentration is generally higher than is submerged fermentation; product concentration is generally higher than in submerged cultures; it is the only technique that yields true mushroom fruiting bodies and it can be used not only for production of crude enzyme concentrates (koji) but also for raising the protein content of high starch substrates. It also can be used to increase the content of vitamins at low cost. Disadvantages of “solid‐substrates”from the modern industrial processing view point are the greater difficulty of handling solid substrate and the greater difficulty of controlling the fermentation parameters, temperature, pH and oxygen, and rate of microbial growth compared with liquid submerged fermentations.
Submerged Cultivation of a Fungal Mutant Strain Humicola Lutea 120‐5 Producing Acid Proteinases
Authors: Aleksieva P. , Grigorov I. , Djerova A. , Sheremetska P. , Tchorbanov B.
Published: December 2004

The optimal parameters for the cultivation in 10‐l fermenters of a mutant strain Humicola lutea 120‐5 were established:temperature 30°C, inoculum size 6%, inoculum age 24 h, aeration rate 0,6 vol/vol · min, medium agitation 620 rpm and cultivation time 72 h. A maximal proteolytic activity of 2000 µg tyrosine liberated from 2%casein ml−1 culture filtrate min−1 at pH 3.0 and 40°C was obtained under the fixed conditions. α‐Amylase biosynthesis during the cultivation of H. lutea 120‐5 was observed but it was insignificant to the 72nd h. It is demonstrated that starch can be used as alternative to glucose carbon source. It is proved that the mutant strain H.lutea 120‐5 produced two acid proteinases.
Sorption of penicillium‐cellulase on cellulose and lignin
Authors: Shawky B. , Kasulke U. , Philipp B. , Schulz G. , Hirte W.
Published: December 2004

Sorption of Penicillium cellulase onto cotton linters samples differing in physical structure and onto KLASON‐ lignin from spruce has been investigated by determining cellobiase, CMCL‐ and ‘linters‐activity’ as well as protein content of a cellulase culture filtrate before and after contact with the sorbent at different temperature for different time intervals. CMCL‐ and cellobiase‐activity were found to be reduced much less by the sorption process onto the cellulose samples than ‘linters‐activity’ and protein content. Sorption increased in the order: untreated linters < mercerized linters < wet fibrillated (‘colloidal milled’) linters. With the KLASON‐lignin also a considerable sorption of the cellulase system was observed. Results are discussed with respect to preferential sorption of enzyme components.
Inhibierungserscheinungen bei der alkoholischen Gärung, I. Einfluß der Ethanolkonzentration auf die spezifische Ethanolbildungsgeschwindigkeit von Saccharomyces cerevisiae
Authors: Richter K. , Becker U.
Published: December 2004

Differential values of the specific ethanol production rate \documentclass{article}\pagestyle{empty}\begin{document}$$ v_{(t)} = \frac{1}{{x_{(t)} }} \cdot \frac{{dP}}{{dt}} $$ \end{document}
can be calculated exactly from experimental batch fermentation process data by use of a nonlinear regression programme. The method used is based on the fact, that the function P = f(t) can be approximated by an exponential equation. The specific ethanol production rate is calculated then from the first differential derivation of this equation using the appropriated values of actual biomass concentration. For two strains of Saccharomyces cerevisiae a linear and nonlinear kinetic pattern, respectively, was found for product formation. This result can be explained by a simple mathematical relation according to ν=ν0 − a . Pb,in which the exponent becomes 1 in the case of linear kinetic pattern.
Enhancement of enzymatic degradation of cellulose by application of mixed enzyme systems of different fungal origin
Authors: Szakäcs‐Dobozi M. , Szakäcs G. , Meyer D. , Klappach G.
Published: December 2004

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.
Nucleic acid reduction from yeast activation of intracellular rnase
Authors: Bueno G. E. , Otero M. A. , Klibansky M. M. , Gonzäles A. C.
Published: December 2004

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.
Spektralphotometrische in‐situ‐Messungen der diffusen Reflexion bei der mikrobiellen Kohlenwasserstoffwandlung
Authors: Bayer C. , Iske U. , Glombitza F. , Nagel B.
Published: December 2004

The spectrophotometrical measurement of the diffuse reflectance in fermentation media has been proved useful for the analytical control of the microbial biosynthesis and transformation. A laboratory steril fermenter was fitted at an UV/VIS‐spectrophotometer equipped with a diffuse reflectance attachment. The apparent absorbance ΔE8(328) of aromatic hydrocarbons and the reciprocal scattering E8(650) have been compared with parameters of the discontinuous fermentation of the yeast Lodderomyces elongisporus and the bacteria strain EB 10c on petroleum hydrocarbons as a substrat.
The inhibitory effects of pyrocarbonic acid diethyl ester on lactobacillus casei and its phage Jl – A novel strategy for phage control in technical fermentation processes
Authors: Murata A.
Published: December 2004

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.
Wechselwirkungen zwischen Lektinen und Mikroorganismen II. Identifizierung von Mikrobiellen Stämmen und Mutanten durch die Kinetik induzierter Agglutinationen
Authors: Flemming Ch. , Sattler K. , Flemming I.
Published: December 2004

The kinetic of lectin or antibody induced agglutination between single cells in a complex but highly specific reproducible marker. It is useful for the identification of strains and mutants. Using the described method we are able to differentiate the mutants of yeast strains.
Wirkung von Ölen und fettsäuren auf Wachstum und Enzymbildung bei Thermoactinomyces vulgaris. VI. Studien zur Wirkungsweise von Öl
Authors: Leuchtenberger A. , Jakovleva M. B. , Ruttloff H. , Loginova L. G.
Published: December 2004

Some aspects on the action of vegetable and animal oils and fatty acids on growth and protease synthesis of T. vulgaris were studied to interpret the stimulating effect of these substance. It was found that oil does not influence the hydrolysis of the substrate casein by the protease. However, the effect on the gas exchange during fermentation has a substantial importance. Furthermore, the metabolization of lipids shows that they play a role as carbon source.
Einfluß einiger Faktoren in Abhängigkeit von den Methoden bei der Immobilisierung eines bakteriellen Enzympräparats mit Milchkoagulationswirkung
Authors: Dobreva E.
Published: December 2004

The influence of different factors (binding time, pH, temperature, and enzyme/carrier ratio) on the efficiency of immobilization of enzyme preparation with milk clotting activity from Bacillus mesentericus M strain by use of different carriers and methods of binding was investigated. It has been established that the dependence of immobilization from pH is most pronounced and is mainly influenced by the nature of the carrier. The binding time is of essential importance only by immobilization through adsorption. The temperature has not any influence on the efficiency of immobilization of the indicate preparation. Saturation of many of the used carriers by the different methods for immobilization was achieved at enzyme/carrier ratio 1 : 10, with exception of the cases where glutaraldehyde was used as binding reagent. In this case then the ratio was 1 : 4.
Fluorimetrische und photometrische Schnellbestimmung von L‐Lysin in Fermentationslösungen
Authors: Hesse G. , W. Römer , Miosga N. , Wachtel E.
Published: December 2004

In a methodical paper two analytical‐chemical procedures are described which concern the control of L‐lysine formation during fermentation processes. On one hand lysine is determined fluorimetrically with o‐phthalaldehyde at defined pH, on the other spectrophotometrically with ninhydrine in acidic medium. The analytical conditions are discussed with respect to specifity, interferences, accuracy and reproducibility. A comparison of values with Autoanalyzer technique and two other methods for lysine determination offers the possibility to decide in what manner and with which aim of desired accuracy, economy and rapidity a given specimen has to be analyzed.
Effects of temperature on microbial ethanol production I. The temperature profile curve of ethanol production of the yeast strain saccharomyces cerevisiae Sc 5
Authors: Richter K. , Becker U.
Published: December 2004

The temperature‐profile curve of ethanol production of the yeast Saccharomyces cerevisiae Sc 5 is shown. Accordingly the biokinetic sphere of ethanol formation consists of 5 ranges. The maximum specific ethanol formation rate v0 is reached within the temperature limits of 32°C ≦ T ≦ 36°C, and the maximum temperature for ethanol formation amounts to T″max = 57°C. Within the first suboptimum temperature range ethanol formation is not retarded thermally. Using a modified ARRHENIUS equation the activation energy of ethanol formation was calculated to be ΔHÊtOH = (78.5 ± 2.2) kJ/mol.
Auswirkungen der Methode der Linearisierung des μ‐cs‐Verlaufs auf die Parameteranpassung bei dem Monodschen Modell
Authors: Stiebitz O. , Wolf K.‐H. , Klöden W.
Published: December 2004

Nowadays, the MONOD conception is the foundation for modelling the growth‐connected substrat consumption. The methods of the parameter estimation for μmax and Ks have a variable exactness. Using the experimental MONOD's data [1] variable graphical and numerical methods are analyzed from the point of statistical view. Appropriate objective functions are proposed.
Dynamics, regulation, block description and optimal performance of cellular metabolism in open conditions: Outline of a unifying concept
Authors: Reich J. G.
Published: December 2004

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.
Einflußder Aufbewahrungsmethode auf die Stabilität der biotechnologischen Eigenschaften von Zellulose utilisierenden Pilzen
Authors: Hornecka D. , Czajkowska D. , Ilnicka‐Olejniczak O.
Published: December 2004

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.
A fed‐batch cultivation method for the simultaneous utilization of glucose and formate by yeasts
Authors: Müller R. H. , Zimmermann E. , Babel W.
Published: December 2004

A fed‐batch cultivation method was elaborated which 1. warrants simultaneous consumption of glucose and formate, 2. is easy to employ and provides reproducible results, 3. gives information about the role of formate in yeast growth, 4. results in almost identical conditions for parallel cultures on glucose and glucose/formate. The method was applied to Hansenula polymorpha and Saccharomyces cerevisiae. Relevant results were obtained and were comparable to those found previously under chemostatic conditions. Thus, the method is considered suitable for comparative investigations of yeast growth on glucose/formate to demonstrate the role of formate as an additional energy donor.
Rapid determination of L‐lysine with an enzyme electrode by steady state and kinetic measurement
Authors: Weissbach F. , Kreibich G. , Bartels K. , Schülke W.
Published: December 2004

Fast and simple methods of determination of L‐lysine by a potentiometric enzyme electrode based on a CO2 electrode and L‐lysine decarboxylase are described. Measuring devices for manual and automated operation for steady state response measurement as well as kinetic measurement are compared. Sample frequency may be increased by decreasing the time of a measuring cycle.
Hopf bifurcation for a family of two‐state microbial growth models
Authors: Bley Th. , Wegner B.
Published: December 2004

We describe a family of two‐state microbial growth models, in which growth and maintenance are assigned to two different cell states. The way of splitting periodic solutions for low dilution rates of a continuous fermentation is shown. The existence of these periodie solutions is mainly influenced by the properties of substrate consumption, which the maintenance rate in the second cell state amounts to.
Production of cellulases and xylanase by Trichoderma reesei F‐522 on pretreated wheat straw
Authors: Szczodrak J.
Published: December 2004

Autohydrolyzed and ethanol‐alkali pulped wheat straw was examined as a candidate feedstock for both cellulase and xylanase production and enzymatic hydrolysis. Submerged cultures of Trichoderma reesei F‐522 grown on hydrothermally modified straw provided culture supernatants of the highest enzymatic activities, whereas the maximal efficiency of enzymatic hydrolysis was recorded in straw treated with ethanol‐NaOH mixture. Some culture conditions were optimized to improve the growth and cellulase production by T. reesei on autohydrolyzed wheat straw.
Purification and properties of two β‐glucosidases isolated from Aspergillus niger
Authors: Witte K. , Wartenberg A.
Published: December 2004

The cellulase complex of the fungus Aspergillus niger (strain CBS 554.65 = ATCC 16 888) was fractionated by gel filtration yielding six pronounced peaks. Only proteins from the fraction corresponding to the first peak (96 kDa) showed β‐glucosidase activity vs. the substrate 4‐nitrophenyl‐β‐D‐glucopyranoside (pNPG). These proteins have been fractionated by chromatofocusing, yielding two β‐glucosidases (I and II) which are shown to be homogeneous in isoelectric focusing experiments (pI = 4.6 and 3.8, respectively). Kinetic experiments with pNPG, MU‐glucopyranoside and cellobiose revealed that both types of β‐glucosidases behave like aryl‐β‐glucosidases. β‐Glucosidase‐I acting on pNPG exhibits a split kinetics characterized by high and low substrateconcentration kinetics which are differentiated by different values of V and of Km. In addition, β‐glucosidase‐II is shown to be an exo‐glucohydrolase as deduced from experiments with MU‐cellobiopyranoside.

Experimental features should be emphasized; usual soft‐gel ion‐exchange materials did not work in the chromatofocusing separation of the two β‐glucosidases, in contrast to the 10μ‐Si 500 = DEAE exchange material (Serva) typically used in HPLC‐experiments. Furthermore, protein content determinations based on different procedures yielded widely differing values.
Controlled porous glass (CPG) with reactive epoxy groups as support for affinity chromatography I. Optimization of CPG modification and the binding of glucose with modified surface
Authors: Rogalski J. , Dawidowicz A. L.
Published: December 2004

The selective and complementary interaction between the ligand bound to support surface and isolated substance is the key of the affinity chromatography. This is the reason of the research in the field of certain sorbents. They are obtained by chemical reaction of matrix with proper ligands. It is carried out mainly by using bifunctional substances which make the reaction with the ligand in question possible. This paper deals with the preparation of controlled porosity glass with reactive epoxy groups. In order to obtain such support and avoid application of a proper epoxy silane compound, the double‐step reaction using simple agents was employed. The sorbent syntheses were optimized. The prepared sorbents were applied for coupling some carbohydrates and amino acids.
Energetic efficiency of complex substrate utilization by trichoderma viride
Authors: Leite M. , Apine A. , Zeltina M. , Shvinka J.
Published: December 2004

The efficiency of carbon substrate utilization is evaluated as the thermodynamic efficiency (ηx) of microbial growth.

Three methods based on mass‐energy balance are used for the efficiency studies of complex substrates (straw, plant juices, lye) utilization by microfungi Trichoderma viride.

According to substrate and biomass balance ηx = 0.55, 0.37 and 0.36 for Trichoderma viride growth on alkali pretreated wheat straw during 23, 34 and 50 hours. Cellulose biodegradation increases with cultivation time. However, the efficiency of cellulose utilization for cell mass growth decreases at the same time.

In accordance with oxygen‐balance calculations ηx = 0.75 and 0.71 for the same processes. The discrepancy in results from the above two methods probably can be explained by the following:

Substrate and biomass balance gives underestimated results.

Oxygen balance method includes the part of energy for extracellular product formation and therefore ηx can be overestimated.

The efficiency of complex soluble substrate utilization (lye, green juice, deproteinized brown plant juice) tested by means of pulse method gives the values of ηx = 0.72 – 0.88. Similar high estimates of ηx in C‐limited batch culture are observed for soluble carbohydrates (glucose, galactose, lactose, xylose) but not for acetate. The pulse method is advantageous for testing the “true” efficiency of carbon substrate utilization in a definite physiological environment.
Degradation of L‐arabonate by extracts of different filamentous fungi
Authors: Elshafei A. M.
Published: December 2004

Ten Aspergilli and Penicillia were tested for the capabilities of their extracts in degrading L‐arabinose or L‐arabonate nonphosphorolytically. L‐arabonate dehydratase was nearly absent, while the reverse reaction of 2‐keto‐3‐deoxy‐L‐arabonate (KDA) aldolase was operative in extracts of all the tested organisms grown on L‐arabinose or L‐arabonate as the sole carbon source. Degradation of different related substrates by cell‐free extracts of Aspergillus ustus showed that L‐arabonate, D‐gluconate, D‐galactonate and D‐galactonic acid‐γ‐lactone were degraded under these conditions. Chromatographic studies identified the L‐arabonate degrading products of such degradation in A. ustus as KDA (traces), pyruvic acid and α‐ketoglutaric acid.
Degradation of some sugars and sugar acids by the nonphosphorylated D‐gluconate pathway in Aspergillus ustus
Authors: Elshafei A. M.
Published: December 2004

The degradation of fifteen sugars, sugar acids and related substrates were examined using cellfree extracts of Aspergillus ustus growing on D‐glucose, D‐mannose, D‐galactose or D‐gluconate as the only carbon source. D‐gluconate was superior for the induction of the enzymes capable for the degradation of some of these substrates. The addition of 0.5% malt extract with D‐gluconate to the growth medium or the presence of shaking conditions resulted to an increase in the degradation of those substrates, whileas the incorporation of 0.5% malt extract alone to the medium has no effect. Extracts of D‐gluconate‐grown mycelia of A. ustus degraded D‐gluconate > D‐galactonate > 1 : 5 gluconolactone and > L‐arabonate nonphosphorolytically more effectively. Optimum pH and temperature for the degradation of D‐gluconate were found to be 8.0 and 40°C, respectively. Thermal stability studies on the behaviour of D‐gluconate dehydratase showed that this enzyme was stable at 50°C and 60°C for 30 and 5 minutes, respectively. Specific activity of this enzyme was increased three times when cell‐free extracts were incubated at 60°C for 5 minutes. MgCl2 and CoSO4 were good activators, while CaCl2 p‐mercurychlorobenzoate (PMCB), sodium arsenite, ZnSO4, CuSO4, iodoacetic acid, MnCl2 and FeSO4 were potent inhibitors for D‐gluconate dehydratase activity. Km was calculated for D‐gluconate and found to be 2.5 × 10−2 M.
Charakterisierung der Stärkehydrolysate nach Einwirkung einer thermostabilen α‐Amylase
Authors: Dobreva E. , Ivanova V.
Published: December 2004

The action of thermostable α‐amylase produced by Bacillus licheniformis 44MB82 strain on soluble and insoluble starch, amylose and amylopectin at temperatures 30°C and 90°C was studied. The hydrolysis of soluble starch proceeded rapidly for 10 to 15 minutes after which the maltodextrins thus formed were further dissociated. In the course of 60‐minutes enzyme treatment mainly glucose, maltose and maltosugars (from G3 to G6) as low molecular weight products were found and the formation of maltcse and maltotriose was increased by the longer treatment. The hydrolysis of insoluble starch and amylopectin proceeded in the same way while the amylose was hydrolysed slowly.
Heterotrophic eubacteria isolated from cultures of the cyanobacterium, spirulina maxima
Authors: Davis J. E. , Jones L. P , Zajic J. E.
Published: December 2004

Three distinct heterotrophic eubacterial strains were isolated from mixotrophic cultures of the filamentous cyanobacterium, Spirulina maxima (Gom) Geitl. Spirulina spp. are considered to be prime candidates for the phototrophic production of biomass protein, particularly in developing countries. These cyanobacteria are extreme alkaliphiles and halophiles, making their production in arid regions promising.

Most previous studies on the eubacteria which live in Spirulina culture systems have focused on determining the possible presence of pathogenic species in biomass protein. Little has been done to understand the symbiotic relationships between the cyanobacterium and its eubacterial cosymbionts. From the perspective of a heterotrophic eubacterium, autotrophic cultural systems of Spirulina have limited carbon and energy resources, being limited to cyanobacterial exudates.

In this study, three eubacterial strains were isolated and studied. One strain, a Gram‐negative, non‐sporing, motile rod, grew exceptionally well in a mineral salts medium where only a small amount of a single low molecular weight organic compound (e.g., acetate) was supplied as sole energy source. This strain was also extremely euryresponsive with respect to salinity and alkalinity as well. Two less well‐adapted eubacterial strains are also described.
Nachweis humoraler und lokaler Antikörper nach Einsatz einer bordetella Bronchiseptica‐Lebendvakzine am Schwein
Authors: Mitro S. , Krüger M. , Horsch F. , Kiessling S.
Published: December 2004

The aim of this work was to prove if a Bordetella bronchiseptica living vaccine is able to induce humoral and local antibodies in pigs. The living vaccine was compared with a killed Bordetella bronchiseptica adjuvans vaccine. The results show that piglets of sows vaccinated parenterally with living vaccine and killed adjuvans vaccine develop a stronger humoral immune reaction than piglets vaccinated locally with living vaccine. Sows immunized parenterally with living vaccine permint their piglets in the first three weeks colostral antibodies like sows immunized with killed adjuvans vaccine. The living vaccine induces especially local antibodies.
Anwendung von Methoden der Mustererkennung bei mikrobiell hergestellten Trockenproduktchargen
Authors: Noetzel R. , Schulz P.
Published: December 2004

The application of methods of Pattern Recognition makes it possible to classify dehydrated SCP‐products which were produced under various conditions of production by a low number of signs. These mathematical methods not only allow to draw technological conclusions but also to decide on correctness of the way to produce suitable SCP‐products for feeding of monogastric animal species. There are a large number of possibilities to use these methods of Pattern Recognition in the field of biotechnological research.
Verfahren zur Produktion von ColE1‐verwandten Plasmiden
Authors: Neubauer P. , Hofmann K. , Riethdorf S. , Hecker M.
Published: December 2004

The plasmid ColE1 and its derivatives are the most commonly used vectors in gene cloning experiments. A very often used method to obtain a sufficient amount of plasmid DNA is to treat exponential growing cells of Escherichia coli containing plasmids with chloramphenicol [2]. An amplification of these plasmids is also possible in Escherichia coli relA mutants if one of the necessary amino acid limits the growth [8]. On the basis of this system a fed‐batch fermentation process was developed with a ten times higher yield of plasmid DNA than the method based on chloramphenicol.
Growth and dinitrogen fixation by azospirillum, species grown under various growth conditions
Authors: Shawky B. T.
Published: December 2004

The effect of strain specificity, various culturing conditions, and incubation periods on the growth and efficiency of dinitrogen fixation by A. lipoferum and A. brasilense, grown in semisolid N2 malate medium was investigated.

The properties of the particular strain markedly affected the proliferation as well as the nitrogen gains of Azospirillum in either growth condition. In A. lipoferum strain 1244 and A. brasilense strrain 1771 the multiplication rates were much higher, the counts reaching 7 × 106 and 9 × 106 cells/ml after 15 days in case of 50/300 ml growth condition, associated with high nitrogen gains reaching 99.8 and 114.3 mgl−1, while in A. lipoferum strain 8670 and A. brasilense strain 5677 the counts were 6 × 105 and 2 × 106 cells/ml after both the same period and growth condition, associated with low nitrogen gains, reaching 62.5 and 69.6 mgl−1, i. e., the amounts of nitrogen fixed is usually linked to cell proliferation. The microbial activity in both nitrogen fixation and oxidation of carbonaceous material is directly reflected on the efficiency of dinitrogen fixation. In all treatments the efficiency of N2‐fixation generally increased markedly with time. In A. lipoferum strains 1244 and 8670 the efficiency of N2‐fixation was 118.5 and 107.4 in case of 50/100 ml growth condition after 20 days, while in A. brasilense strains 1771 and 5677 the corresponding figures were 126.5 and 115.4. The response of the available oxygen was linked to the growth conditions, accordingly, the efficiency of N2‐fixation increased by 4.4% & 8.8% in case of A. lipoferum strains 1244 and 8670, and 11.0% & 9.8% in case of A. brasilense strains 1771 and 5677 as a result of increasing the surface area: depth ratio by altering the volume of medium in the experimental flasks.
Effect of organic growth factors upon the biomass production of some yeasts
Authors: Kamra N. , Madan M.
Published: December 2004

Some asporgenous yeasts, isolated from various fruits have been examined for their organic growth factor requisites. Of the fifteen growth factors tested, thiamine, biotin, pyridoxine and inositol are the most commonly required organic growth factors by the yeasts, whereas rest of the growth factors showed variable essentiality. All the species of yeasts investigated required different concentrations of growth factors for their optimum growth. Concentration higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied.
Intensification of glucose oxidase synthesis with aspergillus niger by the way of multistage mutagenization
Authors: Fiedurek J. , Rogalski J. , Ilczuk Z.
Published: December 2004

Conidia of glucose oxidase active Aspergillus niger G 13 strain were subjected to the fourth‐stage mutagenization using different combinations of mutagens in each stage (stage I – UV radiation + nitrosomethylurea, stage II – UV radiation + ethyleneimine, Stage III – acryflavine, stage IV – UV radiation + N‐methyl‐N′‐nitrosoguanidine). In all, 400 strains which showed higher glucose oxidase activity with our own diffusion data method (were isolated out of 5208 colonies after mutagenization). Nine most active mutants were tested in the submerged culture determining the activity of glucose oxidase in the post‐culture liquid which increased from 10.7 to nearly 30%.
Production of active mutant strains of penicillium canescens 20171, forming complex preparation of exogenous glycosidases
Authors: Lomkatsi E. T. , Radiani T. Sh. , Shkolni A. T. , Bilai T. I. , Gomarteli M. M. , Jobava M. D. , Tsereteli A. K. , Kvesitadze G. I.
Published: December 2004

The ability to synthesize extracellular β‐galactosidase (EC 3.2.1.23), α‐galactosidase (EC 3.2.1.22), β‐fructofuranosidase (EC 3.2.1.26) in Penicillium canescens mutant strains (300 cultures) after UV‐irradiation has been checked. Most of the investigated mutants had the ability to produce the mentioned enzymes in an increased amount in comparison with initial strain. The ability of extracellular enzyme biosynthesis in P. canescens mutant strains was increased for α‐galactosidase on 200%, for β‐galactosidase on 275% and for β‐fructofuranosidase−220%. The mutant strains were stable during three years of observation, complitely maintaining increased activity.