bluuebunny/crossref_metadata_2025 huggingface dataset:
Saccharification of cassava peels waste for microbial protein enrichment
Authors: Odunfa S. A. , Shasore S. B.
Published: December 2004

Cassava waste peels may constitute up to 55% of the original tuber. These waste peels were found to contain 41.8% carbohydrate, 1.1% protein, 12.5% ether extract and 4.9%, 4.9% total ash. and 20.8% crude fibre. Studies were conducted to formulate a fermentation medium to convert the waste peels to reducing sugars and to enrich the peels with microbial protein. Amylase producing microorganisms were isolated from rotten cassava tuber discs buried in the soil at different locations. The microorganisms isolated were Aspergillus fumigatus, A. flavus, A. niger, and a Pseudomonas sp. and A. niger; the level of reducing sugar was 20.5 mg/ml. The lowest was by B. subtilis an isolate from fermenting locust bean. Generally the levels of saccharification were higher when the waste media were supplemented with different nitrogen sourses. The crude protein yield in the cassava peel waste media by different microorganisms varied from 5.6% to 17.5%. The highest protein yield was in the waste medium fermented by A. fumigatus followed by A. niger, B. subtilis, Pseudomonas sp. in decreasing order.
Production of single‐cell protein with cellulomonas sp. on hempstalk wastes
Authors: Jeder H. , Deschamps A. M. , Lebeault J. M.
Published: December 2004

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.
Zur Wechselwirkung zwischen einer Penicillium‐Cellulase und wasserlöslichen Cellulosederivaten
Authors: Kasulke U. , Philipp B. , Polter E.
Published: December 2004

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.
Particularities in the kinetics of growth and citric‐acid accumulation by saccharomycoposis lipolytica
Authors: Behrens U. , Thierrsch A. , Weissbrodt E. , Stottmeister U.
Published: December 2004

When glucose is used as C‐source extracelluar citric‐acid accumulation does not start at the point of N‐source exhaustion. A transition phase lasting for about 2–3 hours is observed. It may be assumed that the continuation of growth after the N‐source exhaustion coincides with the delay of the citric‐acid accumulation. During the course of citric‐acid production characteristic interruptions of the glucose uptake and the citric‐acid accumulation are found. The findings are discussed in more detail.
Formation of higher alcohols and phenol by strains of zymomonas sp.
Authors: Rao S. C. , Jones L. P.
Published: December 2004

Strains of the bacteria Zymomonas sp. were studied for their ability to form higher alcohols. In a complex growth medium, six strains were shown to produce significant amounts of 1‐propanol, 1‐butanol, 2‐methyl‐1‐butanol, 3‐methyl‐1‐butanol, 2‐methyl‐2‐butanol, pentanols, secondary hexyl‐alcohols, and trace amounts of n‐hexanol. When resting cells of these organisms were placed into a fermentation medium containing glucose and Tris‐buffer, Z. mobilis 8938 produced increased levels of 1‐butanol, and secondary hexyl‐alcohols at concentrations of 13.5 mg/liter and 5.8 mg/liter, respectively. Another strain, Z. mobilis subsp. mobilis B 806, stimulated the formation of 1‐propanol and 1‐butanol at concentrations of 14.9 mg/liter and 23.52 mg/liter, respectively. Amino acids or amino acid precursors were then added to the fermentation medium. The presence of threonine and α‐ketobutyric acid stimulated Z. mobilis 8938 to produce 82.6 mg/liter secondary hexyl‐alcohols and 8.0 mg/liter n‐hexanol, respectively. Isoleucine and valine increased the production of 2‐methyl‐1‐butanol (394.0 mg/liter) and 3‐methyl‐1‐butanol (113.4 mg/liter), respectively, by Z. mobilis subsp. mobilis B 806. Glutamine enhanced the formation of 2‐methyl‐2‐butanol production to concentrations 38.8 mg/liter in Zymomonas strain B 806. Additional experiments suggested that higher alcohol production could also be accomplished in the absence of glucose when cells were allowed to metabolize the precursors only. The effect of aromatic amino acids on phenol production was determined using resting cells of Zymomonas sp. The maximum yield of phenol (111.6 mg/liter) was found by Zymomonas strain 8938 in the presence of tyrosine. The addition of phenylalanine also stimulated this strain to form 71.4 mg/liter of phenol.
Einsatz eines Hybridrechnersystems zur Prozeßführung von Antibiotikafermentationen in einer Scale‐up‐Linie
Authors: Reimann B.
Published: December 2004

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.
Continuous ethanol production by zymomonas mobilis on an industrial scale
Authors: Sahm H. , Bringer‐Meyer St.
Published: December 2004

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.
Regulation of sterol synthesis by glucose in baker's yeast
Authors: Novotný Č. , Běhalová B. , Doležalová L. , Zajíček J.
Published: December 2004

The ability of ten baker's yeast strains to synthesize sterols was checked. Ergosterol/24(28)‐dehydroergosterol (E/D) ratio had the value of 0.8 to 1 in most strains grown in a medium containing molasses as the carbon source. The ratio values were significantly increased in the cultures grown in a glucose medium. Both a decrease in the content of 24(28)‐dehydroergosterol and a slight increase of the ergosterol content were found to be responsible for the high values of E/D in the glucose‐grown cells. The strains examined could be divided into three groups on the basis of their behaviour towards glucose. The effect of the type of cultivation on sterol accumulation is demonstrated by comparing the sterol content of the representatives of the three groups of baker's yeasts grown in a fermenter or in shaken flasks.
Automatisiertes Laborfermentorsystem mit Mikrorechner „Elektronica‐60”︁ gekoppelt
Authors: Levitan J. S. , Viesturs U. E. , Kristapson M. Z. , Dunce M. E. , Arakeljan V. V. , Sarkissjanz L. S.
Published: December 2004

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”.
Einfluß des furfurals bei der Sulfitablaugeverhefung
Authors: Fischer K , Mohrmann K.‐H.
Published: December 2004

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.
Enhanced Formation of β‐Glucosidase by Aspergillus niger VKMF‐2092 in Fed‐Batch Operation with Frequently Intermittent Glucose Addition
Authors: Kerns G. , Okunev O. N. , Ananin V. M. , Golovlev E. L.
Published: December 2004

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.
Ammonium‐nitrogen metabolism and nitrogen fixation in azotobacter vinelandii
Authors: Shawky B. T. , Ghali Y. , Ahmed F. A. , Kahil T.
Published: December 2004

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.
Zum zeitlichen Verlauf von Substratkonzentrationsprofilen in einer Enzymträgerkugel
Authors: Carl S.
Published: December 2004

In this paper the time evolution of substrate concentration profiles in spherical particles with homogeneous enzyme distribution is investigated. It turns out that the concentration S  S(x, t) is monotone increasing in the time variable t against the uniquely defined steady state Ŝ  Ŝ(x). Explizit formulas are derived for the estimation of the difference between the steady state Ŝ and the presteady state S, that hold for all t ≧ 0, i.c., it is not only determined the order of magnitude of the convergence for sufficiently large t.
Identifizierung prozeßspezifischer lag‐Zeiten und Berücksichtigung bei der Berechnung phänomenologischer Wachstumsparameter
Authors: Reimann B. , Mund K.
Published: December 2004

A significant difference between the maxima of the specific growth rate (μ) and the specific product formation (kp) may indicate a retarded correlation model of biomass (X) and product (P).

Therefore phenomenological growth parameters which connect X and P or their derivations (Yp/x, kp) have to take into consideration this kind of lag‐time in the same way.
Microbial lipases in biotechnology
Authors: Sztajer H. , Zboińska E.
Published: December 2004

The lipolytic activity of microorganisms and substrate specificity of lipases are described. The applications of these enzymes in various industrial processes are discussed.
Solid substrate growth of white rot fungi on coffee pulp
Authors: Rolz C. , De Leon R. , De Arriola M. C.
Published: December 2004

The presence of several antiphysiological factors limit the use of coffee pulp in monogastric and ruminant feeding. Twenty six white rot fungi were grown under solid substrate conditions in previously ensiled and pressed coffee pulp without adding additional sources of nitrogen. All grew and wholly covered the surface of the substrate. Six of them produced fruiting bodies. The weight loss interval ranged between 6.7–28.0% dry matter before fructification and from 17.0 to 48.7% after fructification. Some fungi biodegraded about 70, 55 and 47% of the total polyphenols, caffeine and permanganate lignin present in the original substrate.
Transformation of 7,8‐dihydrocodeinone to 7,8‐dihydroisocodeine by Aureobasidium pullulans
Authors: Fuska J. , Khandlová A. , Proksa B. , Fusková A.
Published: December 2004

Aureobasidium pullulans reduced stereospecifically 7,8‐dihydrocodeinone to 7,8‐dihydroisocodeine. Activity of the culture was inhibited by some substances present in the malt extract.
Stable ionotropic gel for cell immobilization using high molecular weight pectic acid
Authors: Berger R. , Rühlemann I.
Published: December 2004

It is shown that Ca‐ and Al‐pectate gel beads prepared by use of high molecular weight polygalacturonic acid (viz. polygalacturonic acid having a high STAUDINGER index) are well suited for cell immobilization. The pectate beads are much more insensitive to those ions and chemical agents which destructively act on alginate beads (such as phosphate, citrate, gluconate, lactate as well as a high excess of sodium, potassium, and/or ammonium ions), even without addition of gelling cations to the liquid phase.
Ein neues Verfahren zur zweistufigen Kultivierung von Mikroorganismen. Teil I. Prinzip des Verfahrens
Authors: Teich W.
Published: December 2004

The importance of the two‐step process technology in the field of biotechnological processes is demonstrated. Its application especially is pointed out to waste water treatment. The general advantages of such processes exist in its possibility to use different strains of microorganisms in an effective way and to realize parameters of the technological process in a defined sequence. But with the application of two‐step process techniques (add of biomass to the second step) an extension of retention time is connected with a decrease of yield coefficient. This disadvantage may be eliminated by an inactivation of microorganisms after the first step. The inactivation of microorganisms can be realized by increase of temperature, of pH‐value or by addition of toxic substances. The inactivated microorganisms act as inert particles in the second step not utilizing substrate and oxygen. The new process regime has a lot of advantages, eg. increase of biomass concentration, increase of utilization of complexe substrates and possibility of coupling different biotechnological processes.
Production of cellulases by Trichoderma reesei QM 9414 in batch and fed‐batch cultures on wheat straw
Authors: Acebal C. , Castillon M. P. , Estrada P. , Mata I. , Aguado J. , Romero D.
Published: December 2004

Trichoderma reesei QM 9414 was grown in batch fermentation on wheat straw pretreated by different methods as the sole carbon source. Cellulase production was maximal with NaOH treated wheat straw at a concentration of 10 g/l and an initial pH of 5.5. The addition of fresh straw produced an elongation of the exponential phase or the beginning of a new exponential phase when the additions were carried out at 50 and 120 h, respectively. Filter paper and carboxymethylcellulase activities decreased as an answer to the addition of wheat straw and the levels were regained at the end of fermentation. The decreases of activities were accompanied by the increases of soluble sugar levels, which decreased at the end of fermentation. β‐glucosidase activity was stimulated by wheat straw addition at 50 h while not by addition at 120 h; however, at the end of the fermentation the levels of activities were both similar to control. The studies of pH stabilities of these enzymes allow assurance that the effect of the addition of wheat straw on the enzyme activities is not produced by the changes of the pH during the fermentation.
Einfluß von D,L‐Ethionin auf Zellkulturen von Ruta graveolens L
Authors: Hertel S. C. , Gröger D. , Schmauder H.‐P.
Published: December 2004

D,L‐Ethionine was added in varying concentrations (0.1–1 mM) to two cell suspension cultures of Ruta graveolens. Growth, alkaloid formation and activities of some shikimate pathway‐specific enzymes in these cultures were estimated. Also the effect of ethionine on shikimate pathwayspecific enzymes under in vitro conditions was followed. Growth is only slightly inhibited in supplemented cultures. Alkaloid formation is drastically reduced in a low‐producing and to a lesser extent in the high producing cell line by ethionine. Activities of DAHP synthase, chorismate mutase, and anthranilate synthase in the presence of ethionine are in different Ruta strains to a varying degree affected.
Kontinuierliche Methanolfermentation mit Hansenula polymorpha MH 26 unter Zusatz von Getreideschlempe und Melasse
Authors: Schneider J. D. , Hadeball W. , Feiler E.
Published: December 2004

The methanol‐utilizing yeast Hansenula polymorpha MH 26 is thermotolerant and grows at 40°C and pH 3.5 with a maximum specific growth rate of 0.23 h−1 on methanol.

In continuous cultivation the maximum cell yield can be improved of 0.35 (methanol) to 0.44 g dry cells/g methanol (mixtures of methanol and stillage) through additional utilization of the essential growth and nutritive substances of stillage.

The utilization of methanol and sucrose (molasses) at various mixtures is simultaneous possible. Investigations of these mixtures with 14C‐marked methanol show an increasing incorporation of methanol of about 20–30% against methanol alone. This effect is caused by the increasing metabolization of sucrose to carbondioxide and additional energy delivery for better assimilation of methanol.
Streptomyceten als Bildner industriell und diagnostisch bedeutsamer Enzyme
Authors: Hartung B.
Published: December 2004

This review deals with known natural enzyme activities of streptomycetes and their applications. This knowledge may help potential users to exploit these organisms for individual purposes. The data given in tables are based on scientific publications and the IUPAC recommendations regarding nomenclature are followed. Included are only enzymes already utilized, with those of the primary metabolism being neglected.
Characterization of the course of D‐glucitol biotransformation by strains gluconobacter oxydans
Authors: Pelechová J. , Kulhánek M. , Gramanová I. , Krejčí J. , Heřmánková V. , Staněk J.
Published: December 2004

Production strains Gluconobacter oxydans used in manufacture of L‐sorbose from commercial D‐glucitol were evaluated by HPLC determination of D‐glucitol, L‐sorbose, D‐fructose, D‐mannnitol, D‐arabinitol, D‐xylulose, and D‐threo‐2,5‐hexodiulose in the course of fermentation. Serious differences were observed among the strains apparently identical by standard methods.
Protein isolate and other fractions for human consumption from the small‐value fish species black sea minnow (spratus spratus phalericus)
Authors: Dalev P.
Published: December 2004

A technology for the fractionation of the small‐value fish species Black Sea minnow (Spratus spratus phalericus) has been proposed. Four valuable fractions with a possibility for utilisation as food and health products have been proposed: the protein isolate, the aminoacid concentrate, the lipid fraction and the fish‐bone fraction.
Biotechnological process for sulphide removal with sulphur reclamation
Authors: Buisman C. , Post R. , Ijspeert P. , Geraats G. , Lettinga G.
Published: December 2004

A new biotechnological process for sulphide removal is proposed. The process is based on the oxidation of sulphide into elemental sulphur, which can be removed by sedimentation. In this study it was found that elemental sulphur and sulphate are the main oxidation products of the biological sulphide oxidation. The settling characteristics become worse as the sulphide concentration increases, due to polysulphide formation. The start‐up phase of this biological system is very short; Only four days are needed to reduce the sulphide concentration of 100 to 2 mg/l at a HRT (Residence time) of 22 minutes. Also some environmental factors were evaluated. The optimal pH is situated in the pH‐range 8.0–8.5. Significantly lower conversion rates are found at pH = 6.5 to 7.5 and pH = 9.0, while at pH = 9.5 the sulphide oxidation capacity of the system detoriates. The process temperature was 20°C, although the optimal temperature is situated in the range 25–35°C. No substrate inhibition of sulphide was found at sulphide concentrations up to 100 mg/l.
UV/VIS diffuse reflectance and fluorescence spectroscopy of glucose fermentation with saccharomyces cerevisiae
Authors: Bayer C. , Nagel B.
Published: December 2004

UV/VIS diffuse reflectance spectroscopy and fluorescence spectroscopy have been used to investigate the cytochrome and pyridine nucleotide spectra during aerobic biomass growth of Saccharomyces cerevisiae followed by an anaerobic ethanol formation process. The cytochrome and NAD(P)H spectra are closely related to fermentation parameters such as biomass growth rate and ethanol concentration.
Importance of bacteriophages in fermentation processes
Authors: Wünsche L.
Published: December 2004

Any bacterial strain can be infected by virulent phages or harbour one or more prophages. Therefore, bacteria‐phage interactions are to be regarded as fundamental properties of bacteria. In current industrial fermentation processes phages can be advantageously employed for the identification of bacterial production strains (phage typing). In some cases phages are involved in the production of enzymes and special substances. The fundamental importance of phages in any technical fermentation process, however, is based on the peculiarities of their obligately parasitic life cycle. The propagation of phages in fermentation processes can cause complete (or at least partial) lysis of the production strains and, consequently, serious disturbances in the production process and considerable economic losses. The phage problem in the fermentation industry has not yet been completely solved. For the protection of technical processes against virulent phages five measures are discussed: phage‐protected sterile fermentation, employment of alternative cultures, employment of phage‐resistant mutants, employment of phage inhibitors, and employment of immobilized bacterial cells. The problem of the protection of bacterial production strains from prophage induction is more difficult and practically unsolved. Two possibilities to minimize the process risk due to temperate phages, the elimination of inducing factors during the fermentation process, and the selection of production strains which are difficult to induce, are discussed.
Irradiation treatment of straw for its microbiological conversion – a method for the production of feed protein
Authors: Peteryaev E. V. , Vetrov V. S. , Pavlov A. V. , Stakheev I. V. , Babitskaya V. G. , Gorbachev V. M. , Glushonok T. G.
Published: December 2004

A method for improving the nutritional value of straw as a substrate for fungal growth by radiation is described. The conditions for fungal growth on a medium containing irradiated straw of winter rye were studied. It was found that the straw substrate improves both the quantity of carbohydrates and the quality of their composition in the nutrient medium. Easier accessibility of the irradiated substrate to enzymatic hydrolysis allows the time bioconversion of cellulose into protein to be reduced and the protein yield to be increased, thus improving the qualitative composition of the fungal biomass. The data obtained suggest a possibility of converting straw into a fodder product by substituting the method of using reagents for pretreatment by a simpler and less labour‐consuming method.
Enzyme production by growing cells of acinetobacter in presence of sophoroselipid and triton X‐100
Authors: Hommel R. , Götzrath H. , Kleber H.‐P.
Published: December 2004

The effects of an extracellular microbial glycolipid, the interfacial active lactonic sophoroselipid, and of Triton X‐100 on strains of Acinetobacter calcoaceticus are compared. Sophoroselipid diminished growth rates on n‐heptadecane. Both surfactants led to the excretion of enzyme activities into the culture medium. Sophoroselipid increased the release of cytoplasmic malate dehydrogenase whereas in presence of Triton X‐100 the quinoprotein glucose dehydrogenase was also excreted in large amounts.
Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC) V. Analysis of organic acids in the 2‐oxo‐D‐gluconic acid synthesis
Authors: Gey M. , Thiersch A. , Rietzschel A. , Nattermueller W. , Stottmeister U. , Nagel B.
Published: December 2004

A HPLC method for the separation of 2‐oxo‐D‐gluconic acid and 5‐oxo‐D‐gluconic acid was developed and applied to the investigation of the microbial glucose conversion to oxogluconic acids.

Using a strongly basic anion‐exchange resin TEAP‐Si 100 Polyol as stationary phase and HCOOH as mobile phase, the oxogluconicacids could be separated. The method was used to investigate the kinetics of product formation during the microbial oxogluconic acid synthesis.
Biosensoren für die Lebensmittelindustrie
Authors: Liebs P. , Riedel K. , Pfeiffer D. , Zimare U. , Lietz P. , Scheller F.
Published: December 2004

Biosensors are obtaining an increasing significance for analytical purposes as well as for on‐line monitoring and control in biotechnological processes [1]. In the special field of food industry enzyme and microbial biosensors are suited. With enzyme sensors one can analyse in mostly high specific reactions many substances – microbial sensors normally are unspecific. But they have the advantage of high stability and there is no necessity of enzyme isolation and purification. On the basis of the manifold of microbial metabolic pathways one can expect a wider range of application for microbial sensors, much more as existent for enzyme sensors. This paper is dealing with a microbial aspartam sensor.
Industrielle Meßgeräte zur Bestimmung der Trübung von Flüssigkeiten
Authors: Geppert G. , Thielemann H. , Langkopf G.
Published: December 2004

Three different instruments for the determination of turbidity in liquid media are described. The SLP‐2 was developed for the control of high biomass concentrations in fermenters and is fitted with a self‐cleaning mechanism. The SLP‐3 is used for control of very small turbidities, e.g. in brewery products or in drinking water. The SLP‐4 is designed for continuous measurement of higher turbidities in (waste) water or in different products flowing through pipe‐lines. It may be used alternatively as a submerged probe.
Simultaneous saccharification and fermentation of cellulose: Effect of ethanol and cellulases on particular stages
Authors: Szczodrak J. , Targoński Z.
Published: December 2004

The effects of ethanol and Trichoderma reesei cellulase on the saccharification and fermentation processes as well as the tolerance of the cellulase complex for ethanol have been investigated. The studies were conducted with respect to their usefulness in the process of simulataneous saccharification and fermentation of cellulose to ethanol. The following results were obtained. (1) Fermentative activity of Kluyveromyces fragilis yeasts was gradually depressed with increasing intial ethanol concentrations and temperature of fermentation between 35–46°C. (2) Crude cellulase preparation introduced to the culture broth to a final enzyme activity of 0.5 to 2.0 FPU/ml had not distinct effect on the biomass production, ethanol yield, and glucose uptake by yeasts in 48 h fermentation at 43°C. On the other hand, only a negligible decrease in the cellulase complex activity was observed during fermentation process. (3) Saccharification of wheat straw was inhibited by at least 1% w/v ethanol. (4) The enzymes of the cellulase system showed a high stability to exposure to ethanol for 48 h at 43°C.
A survey of problems relating to legal protection of genetic engineering inventions
Authors: Pehu T. , Gyllenberg H. G.
Published: December 2004

In the first patent applications in the field of genetic engineering the main problems were the terminology and the definition of various concepts. This was mainly due to the fact that the field of genetic engineering was new to the patent officials as well as to the patent attorneys. At the moment the terminology and the concepts have already become familiar and patent problems also in the microbiological sector are merely technical. However, new exiting problems have arisen because of the rapid development in the field of plant and animal biotechnology. A lot of work is still needed before the patent system fulfills its purpose as a promoter of technical, economical and social progress also in the field of biotechnology.
Use of antibodies to the lipopolysaccharide core region in the treatment of gram‐negative sepsis and shock
Authors: Appelmelk B. J. , Verweij‐van Vught A. M. J. J , Brade H. , Cohen J. , Maaskant J. J. , Thijs L. G. , Mac Laren D. M.
Published: December 2004

In this paper we review evidence in favor of a protective role for antibodies directed at the lipopolysaccharide (LPS) core region of Gram‐negative bacilli. It will be shown that, given the right animal model, polyclonal antisera raised against O‐antigen lacking, rough mutant strains, can be shown to protect animals against lethal sepsis due to a variety a bacterial species. Evidence for a protective role obtained from clinical studies will also be discussed. It will be stressed how difficult it is to prove that the antibodies directed against the LPS‐core, and not other proteins present in the polyclonal anti‐rough strain antisera, were responsible for the observed protective effects. The solution to some of these problems is the production of monoclonal antibodies (Mabs). We will discuss the findings that purified anti‐core Mabs may give false‐positive outcomes of protection studies, due to the induction of tolerance by small amounts of contaminating endotoxin, present in the antibody preparation. The need to administer the Mab therapeutically instead of prophylactically to the test animals, will be stressed. It will be shown how we succeeded in determining the epitope‐specificities of several anti‐core antibodies. It will be shown also that use of Elisa alone for characterization of anti‐core Mabs may lead to false conclusions concerning epitope specificities. We will prove that synthetic KDO‐(=ketodeoxycctanate) and lipid A‐containing antigens are indispensable tools for thorough characterization of Mabs. Using this methodology we were able to discriminate between specific antigen‐antibody interactions, and the ability of some Mabs to bind “non‐specifically” to hydrophobic surfaces. The relationship between epitope specificity and protective effects of anti‐core Mabs will be described. Finally, we will demonstrate that a KDO‐specific Mabs is capable of protecting mice against lethal sepsis; in other words, it will be shown conclusively that Mabs to defined epitopes in LPS core region are cross‐protective.
Ethanolic fermentation with saccharomyces cerevisiae cells immobilized in pectate gel
Authors: Rühlemann I. , Richter K. , Berger R.
Published: December 2004

High‐molecular weight pectic acid with a STAUDINGER index of 210 ml/g and a degree of esterification of 3%was used as matrix material for the immobilization of Saccharomyces cerevisiae cells. In discontinuous and continuous fermentation tests the gel beads obtained exhibited the same biomass loading capacity (152–155 g dry wt. cells/kg gel) and about the same maximum specific productivity (103.0 g ethanol/kg gel · h) as alginate immobilizates. But there were distinct differences in the swelling behaviour of the two gels. Under the same experimental conditions the increase of bead volume amounted to 27% only for pectate gel in comparison to 129% for alginate gel. In continuous fermentation experiments performed in a horizontal‐column packed‐bed reactor with liquid recycling a mean steady‐state ethanol concetration of 69.1 g/l and a mean productivity of 24.7 g ethanol/lh could be kept constant over a period of more than 10 days.
Presentation of cell membranes by freeze‐fracture electron microscopy
Authors: Meyer H. W.
Published: December 2004

Freeze‐fracturing is especially suitable for the investigation of membrane structures. In contrast to ultrathin sectioning, large areas of the membranes are exposed. The true surface of membranes, however, can be seen only after etching (vacuum sublimation of ice) because during fracturing the frozen membrane is split between the two lipid layers. The representation of the hydrophobic region of the membrane reveals particles representing integral membrane proteins or, exceptionally, micelles of membrane lipids. Special structures on microbial membranes are, e.g., regular particle arrangements, invaginations and lipid domains with a periodic pattern of curvatures. There are still many unsolved questions concerning these structures, but the occurrence or the alteration of such structures as well as the density of “etching holes” on the membrane fracture face can be used as indicators for membrane perturbations.
Structure and serology of the lipopolysaccharides: Cell components of citrobacter
Authors: Romanowska E. , Gamian A. , Romanowska A. , Łgowski C. , Kułakowska M. , Dabrowski J. , Hauck M.
Published: December 2004

The genus Citrobacter consists of enteric rods that utilize citrate as a sole carbon source. Citrobacter serotypes are normal intestinal inhabitants, but some of them have been reported in gastroenteritis and in extraintestinal infections.

Our immumochemical studies on Citrobacter lipopolysaccharides of chemotype G comprised serotypes: 04, 027 and 036. As we found the serotypes mentioned above are distinguished in having O‐specific polysaccharides that are homopolymers of β [1–2] linked 4‐deoxy‐D‐arabinohexopyranose. In accordance with the structural indentity, the Citrobacter lipopolysaccharides showed strong serological cross‐reactivity. Nevertheless, serotypes 04, 027, and 036 form separate entities, as observed in early studies of serologists. To find the reason for the immunological diversity the structural studies on lipopolysaccharide core regions of these Citrobacter serotypes were carried out. Three novel enterobacterial cores were identified. The complete cores 04 and 036 are decasaccharides differing in one structural element only: side‐chain glucose is present in 04 oligosaccharide in the place of galactose in the 036. The core 027 is octasaccharide.

In conclusion, our structural studies have shown hitherto that in Citrobacter chemotype G group only one O‐specific polysaccharide, but three core regions, exist.
Untersuchungen zur Konstruktion von Bordetella bronchiseptica‐Mutantenstämmen durch Transposonmutagenese und deren Prüfung zur Eignung als potentielle Impfstämme
Authors: Kasprzak H. , Rehak E. , Krüger M. , Horsch F.
Published: December 2004

Three wild type strains of B. bronchiseptica were mutagenized with the transposon Tn 5. Since the transponson Tn 5 encodes resistance to kanamycin, a selection for resistance to these antibiotics can be used as an indicator for Tn 5 transposition.

9 mutants were identified that are not able to grow on minimal medium. Subsequent auxotrophic tests on these mutants revealed 7 valine, 1 cysteine and 1 valine and leucine auxotrophic mutants.

It was not possible for us to find B. bronchiseptica transconjugants in the virulent phase I. All in vivo and in vitro tested parameters showed that the isolated mutants were avirulent in phase III.
Comparison of mitotic activity and growth in two long term callus cultures of matricaria recutita L.
Authors: Čellárová E. , Rychlová M. , A. Seidelová , R. Hončriv
Published: December 2004

Callus cultures of two tetraploid plant of Matricaria recutita L. were initiated from leaves and cultured on LINSMAIER‐SKOOG culture medium supplemented with 0.01 mg · 1−1 IAA or 3.00 mg · 1−1 2, 4‐D for three years. The relationship between mitotic activity and growth of calli was studied. The time at which mitotic activity began in both cultures was different. In the callus culture cultivated on the medium with IAA the maximum mitotic activity was observed on the 14th to 17th day of subculture. In the one cultivated on the medium with 2,4‐D, the increase of mitotic activity was observed earlier and corresponded with the beginning of exponential growth. In addition of total mitotic activity individual mitotic phases have also been evaluated. Most mitotically active cells in both cultures were in prophase. Their courses were similar to those of total mitotic activity. Metaphase and telophase stages were present in low frequency. Anaphase occured rarely. The functional dependences of mitotic activity and growth were characterized by appropriate mathematical models.
The controlled porous glass (CPG) with reactive epoxy groups as support for affinity chromatography. II. Modified CPG as support of substrates or coenzyme of glucose oxidase (GOD) for its purification and immobilization
Authors: Rogalski J. , Dawidowicz A. , Fiedurek J. , Leonowicz A.
Published: December 2004

Controlled porosity glasses (CPG) are materials very widely employed as supports for chromatography and biotechnology. In this paper CPG with epoxy groups have been applied as carrier of FAD, glucose and 2‐deoxy‐D‐glucose. Glucose oxidase (GOD) was highly purified on these sorbents. The purified fraction of GOD was also immobilized on the activated CPG. The presented results suggest the higher stability of immobilized form of this enzyme in relation to the native enzyme.
A new procedure of a two‐step cultivation of microorganisms. Part II. Application to the procedure of SCP‐production on the basis of sucrose
Authors: Teich W. , Otto G. , Bergmann H. , Pätz R.
Published: December 2004

The two‐step cultivation of microoganisms described in part I of this series will be explained by referring to its application to the production of SCP on the basis of sucrose/molasses as carbon sources. The inactivation of the yeast Candida utilis is carried out thermally, and the specific death rate was determined to be between 119 × 10−4 s−1, and 324 × 10−4 s−1, respectively. With this new procedure the apparent productivity could be increased by 96.6%, the yield coefficient of molasses increased by 5.8% and of sucrose by 12.9%. The crude protein content of the product in the case of sucrose rose by 104%. The variability of process design is demonstrated.
Continuous culture models with intermediates
Authors: Petrova T. A. , Ivanitskaya J. G. , Smirnova G. R.
Published: December 2004

The number of stability of steady states of minimal structured models are determined theoretically. Regulation of two “bottle‐necks” of cell metabilism by extracellular or intracellular or intracellular intermediates is suggested. The mechanisms of this regulation include substrate and product feed‐forward inhibition as well as feedback product control. The most complex system behaviour is obtained in models with feed‐forward intermediate inhibition. In particular these models exhibit multistability and two limit cycles.

The maximum number of steady states decreases from five to four when the extracellular intermediate is changed by the intracellular one. The number of non‐zero steady states is changed from four to two.

The relevant features of phase‐portrait appear to be independent of the choice of reaction rates. Therefore our results are suitable for a large group of the third order modles. The possibility to verify the theoretical predictions experimentally is also discussed.
Influence of acid phosphatase activity on the saccharification of potato maltodextrins by aspergillus niger glucoamylase
Authors: Żyła K.
Published: December 2004

A preparation of Aspergillus niger acid phosphatase, which had the temperature optimum 60°C, pH optimum 1.8–3.0; good stability at pH 4–5, the ability to hydrolyze glucose‐6‐phosphate at a high rate, and substantial lack of glucogenic activities, was used simultaneously with a glucoamylase in order to learn its influence on the saccharification of potato maltodextrins.

The addition of the acid phosphatase activity in amounts that gave the 50 fold increase, as compared to phosphatase activity which naturally occurs in the glucoamylase (GA) preparation ‘AMG‐200’, was found to influence on the DE level, mainly at the high substrate concentration (40% d.s.) and low glucoamylase dosage (60–100 GAU/kg d.s.). It may also be possible, when using the acid phosphatase addition, to shorten the saccharification time.
Plant cell cultivation as a biotechnological method
Authors: Schmauder H.‐P. , Doebel P.
Published: December 2004

An overview is given about some aspects of history, principles and application of plant cell and tissue cultivation. The main topics of application discussed in the paper are aspects of plant propagation, plant breeding, techniques for in vitro cultivation, in vitro production of secondary plant products, biotransformations, application of immobilized cells as well as economic aspects of plant cell and tissue culture.
The effect of covalent immobilization on ethanol‐induced, leakage in saccharomyces cerevisiae
Authors: Jirků V.
Published: December 2004

Ethanol‐induced leakage of UV‐absorbing compounds from free and immobilized Saccharomyces cerevisiae cells was studied. The resistance of immobilized cells to this ethanol effect is accompanied with increased levels of phospholipids and sterols. These results suggest a positive role of whole cell immobilization in improving yeast ethanol tolerance.
On the inhibition of laccase by lower fatty acids
Authors: Kreuter Th. , Steudel A. , Pickert H.
Published: December 2004

Laccase (E.C. 1.10.3.2) is slowly inhibited by lower fatty acids in a reversible reaction. The degree of inhibition depends on kind and concentration of the fatty acid, but not on the concentration of the enzyme itself. The degree of inhibition increases with the chain length of the fatty acids. The maximum inhibition was found with butyric acid.
Liquid film bioreactors for cell mass production
Authors: Nikolaev N. A. , Voyonov N. A. , Markov V. A.
Published: December 2004

In order to make heat and mass transfer processes in bioreactors more intensive, the turbulent liquid film flow which is proposed for realization in multitubular reactors has been developed. Experiments have been carried out in tubes with smooth and rough surfaces at cocurrent gas and liquid film downward flows with a view to determine the values of the mass transfer coefficients in turbulent liquid hold‐up in contact tubes. The liquid viscosity and REYNOLDS number are changing in a wide range (from 2000 to 60000).

The results show that the maximum values of the mass transfer coefficients and an acceptable hold‐up can be obtained in tubes with rough surfaces at high REYNOLDS numbers of the liquid film. The results of culturing yeasts on hydrolyzate in a laboratory‐size liquid film fermenter are also presented.
A comparative study of industrial and local yeast isolates
Authors: Olasupo N. A. , Scott‐Emuakpor M. B.
Published: December 2004

The biochemical properties of yeasts isolated from sugary substrates such as nectar, plam wine and sugar cane and identified as strains of Saccharomyces carlsbergensis and Saccharomyces cerevisiae were compared with those of imported industrial yeasts.

The results presented here show that local yeasts better convert glucose, maltose and sucrose sugars at refrigeration temperature of 8°C than the imported ones. Significant differences existed in the amount of ethanol produced by both, the local and imported yeasts. Whereas the imported brewer's yeast exhibited copper sulphate resistance varying from 3.0mM to 7.0mM, the local isolates gave copper sulphate resistance values ranging from 2.0 to 15.0mM. The local yeast isolates also grew and flocculated faster than the industrial yeasts.

The results are discussed in relation to the problems of the brewing industry in Nigeria, a third world's country.
Acid proteinases production by humicola lutea cells immobilized in polyhydroxyethylmethacrylate gel
Authors: Aleksieva P. , Petricheva E. , Konstantinov Ch. , Robeva M. , Mutafov S.
Published: December 2004

The spores of Humicola lutea entrapped in polyhydroxyethylmethacrylate gel were precultivated in production medium for mycelial formation. The immobilized mycelium was reused in batch mode for acid proteinases production. The influence of precultivation time, initial inoculum gel volume, and gel particle size on the enzyme activity and proteinases production half‐life were studied. After 70 h precultivation of the entrapped spores (10 ml initial inoculum volume, 12–27 mm3 gel particle size) maximum proteinases activity of 100–140% (compared with free cells) was registered in 15 reaction cycles. Under the same condition the half‐life time was 18 cycles, while for the free cells it was 5 cycles. The main advantage of the polyhydroxyethylmethacylate immobilized H. lutea was the long acid proteinases production half‐life at a low concentration of outgrowing cells in the medium.
Recent advances in the knowledge of the metabolism of bacterial polyhydroxyalkanoic acids and potential impacts on the production of biodegradable thermoplastics
Authors: Steinbüchel A.
Published: December 2004

Bacteria are able to synthesize a wide variety of different thermoplastic polyhydroxyalkanoic acids (PHA). The physiology of PHA metabolism has been studied in most detail in the aerobic hydrogen bacterium Alcaligenes eutrophus. Strains of this bacterium are already used for the production of biodegradable polyesters on a technological scale. The current knowledge on the pathways for PHA synthesis, on the genes essential for PHA biosynthesis and on genes affecting the accumulation of PHA in this bacterium will be reviewed.