bluuebunny/crossref_metadata_2025 huggingface dataset:
FERM – a decision support system for fermentation processes
Authors: Guthke R. , Schulz V. , Knorre W. A. , Haupt B. , Wernstedt J.
Published: December 2004

For recombinant DNA product fermentations in the laboratory and pilot scale as well as for antibiotic fermentations at the industrial scale decision support program systems for personal computers were developed. It assists the operator to solve control and decision tasks. Applying this program the data and knowledge bases increase, which include measured and derived process data, parameters and comments of previous fermentation runs as well as algorithmic and declarative rules.
Nonionic tensides modify papain structure and proteolytic activity
Authors: Szögyi M. , Cserháti T.
Published: December 2004

The effect of 33 polyethoxylated nonionic tensides with various hydrophobic moieties was studied on the proteolytic activity and phase transition behaviour of papain. Tensides with longer ethyleneoxide chain markedly increased the phase transition temperatures of papain indicating possible hydrogen bond formation between the hydrophilic ethyleneoxide chain and the polar substructures of papain. The character of lipophilic moiety of tensides influences also each physicochemical parameter of papain suggesting the existence of hydrophobic interactions too. The significant positive linear correlations between the activity increasing and structure stabilizing effects of tensides make probably that the structure modification of papain accounts for its enchanced proteolytic activity.
Modelling of the calculation of the power input for aerated single‐ and multistage impellers with special respect to scale‐up
Authors: Möckel H.‐O. , Wolleschensky E. , Drewas S. , Drewas S. , Rahner H.‐J.
Published: December 2004

For both laboratory and industrial scale fermenters the stirred fermenter is often being used. Especially for the design procedure of industrial fermenters with variable speed drive it is important to know the exact power characteristics for single and multiple impellers. The calculation procedure used for estimating the gassed power input gives the possibility to calculate the gassed power drawn by at maximum 3 impellers in vessels up to 3.5 m in diameter in aerated water. For calculation one only needs known parameters. This power input is valid for low and medium viscous fermentation broths too because especially after the addition of antifoam agents the properties of the liquid phase are then comparable to water as a coalescing liquid. It is possible to calculate the gassed power drawn by each impeller of a multiple system. This calculation procedure is applicable to different fermentation broths where in the range of low aeration rates the results differ from those for water.
Ready‐to‐use microbiological culturing set
Authors: Čderský I. , Kybal J. , Sikyta B.
Published: December 2004

A ready‐to‐use microbiological culturing set is described which contains a solid nutrient medium for single use. The set consists of a transparent circular dish with a flange along the upper rim, sterile solid medium, transparent lid with a grip, into which the dish loosely fits, and a multilayer covering foil which provides an air‐tight sealing of the cover. The set can be used without any problems for 2.5 years after its fabrication, as verified by culturing different microorganisms on several solid nutrient media.
A simple and versatile system for fermentation control by on‐line HPLC analysis of medium components
Authors: Koliander W. , Arnezeder C. , Hampel W. A.
Published: December 2004

The configuration and applicability of a system for on‐line determinations of media components by high performance liquid chromatography (HPLC) is described, assembled only from commercial available stand‐alone devices. The fermentation broth is circulated in a bypass through a magnetically stirred filtration unit. The clear filtrate is injected at preset intervals by an electrically actuated valve into the HPLC analysis system. Excess filtrate is circulated back to the fermenter to minimize liquid loss. The system offers aseptic operation, an excellent long‐term stability and a relatively short response time. A wide range of media components is detectable by appropriate choice of analytical HPLC columns and detectors. The system was tested for the analysis of carbohydrates in cultivations of Saccharomyces cerevisiae, Streptomyces olivaceus and Arthrobacter sp.
Evidence for the β‐glucosidase activity and cellobiose fermentation by various kloeckera strains
Authors: Vasserot Y. , Chemardin P. , Arnaud A. , Galzy P.
Published: December 2004

Twenty one yeast strains were tested for their β‐glucosidase activity. Only four produced significant quantities of β‐glucosidase but none of them was able to secrete it. These four strains were tested under fermentative conditions and none of them was able to ferment cellobiose anaerobically.
Features of aspergillus japonicus cellobiase formation and optimization of its production
Authors: Okunev O. N. , Solovjeva I. V. , Michaleva N. I. , Sokolov D. M.
Published: December 2004

We studied some mechanisms of cellobiase formation in Asp. Japonicus VKM F‐2092 aiming at the subsequent development of controlled cultivation to produce the enzyme.

Formation of cellobiase was found to be of noninducible constitutive character. The enzyme was predominantly localized in the cytosole and the periplasm, its minor portion being cell‐wall bound.

The release of the enzyme into the medium was due to autolytic processes.

The two‐phaseness of cellobiase formation in Asp. Japonicus grown on a mineral medium with 0.5% glucose was shown to be determined by the following mechanisms:

Catabolic repression. We established glucose concentrations causing the repression and found it to be dependent on carbon sources in the growth medium.

Catabolic inhibition. Cellobiase activity was found to be inhibited by assumed glucose metabolites in the presence of nitrate nitrogen in the medium.

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Practical recommendations to optimize the process of cellobiase production by Asp. Japonicus are given.
Efficient transformation of thermotolerant methanol & strains of methylophilus spp. via electroporation
Authors: Haider M. Z. , Al‐Taho N. , Al‐Salameen F. , Kadri M. H. , Al‐Amad S. , Spanier E.
Published: December 2004

Plasmid transformation of three thermotolerant strains of methylotrophic bacterium Methylophilus spp. was investigated using three different methods. The plasmids could be transformed by electroporation and were stabily maintained in these methylotrophic bacteria. The calcium chloride (competent cell) method was successful only in the case of one of the three strains studied. Protoplast transformation of methylotrophic bacteria was not successful. The antibiotic resistance markers conferred resistance on the transformants, whereas the wild‐type bacteria were sensitive to the antibiotics.
Growth of thiobacillus ferrooxidans under electrochemical reduction of inorganic energy source used
Authors: Hübner K.
Published: December 2004

An electrolytic cell was designed and constructed for the formentation of T. ferroxidans using Fe2+ as the energy‐supplying substrate. The Fe3+ produced by T. ferrooxidans by fermentation is continuously reduced to Fe 2+ in the electrolytic cell. A suitable version of the electrolytic cell permitted the elimination of most inorganic solid matter (precipitate) from the fermentation process.

The fermentation of T. ferrooxidans was carried out with and without the electrolytic cell. Fermentation with the cell yielded significant rises both in the maximum obtainable growth rate and the biomass concentration.

The experimental of data are discussed and the theoretical substrate consumption coefficient was calculated for Fe2+ as a function of the pH and the coefficient was compared with the experimental results.
Production of lipids from a thermoacidophilic bacillus strain. I. Lipids from bacillus acidocaldarius ZIMET 11274
Authors: Vier B. , Rogge G. , Voigt B.
Published: December 2004

A new isolated Bacillus strain was cultivated continuously at 68°C and pH 3 for a long time. Extractable lipids represent about 3.6% of cell dry weight and are made up of 18% neutral lipids, 39.3% glycolipids, and 42% acidic lipids. Main components of the fatty acid fraction are ω‐cyclohexylundecanoic acid and ω‐cyclohexyltridecanoic acid, respectively. MK‐7 and hop‐22(29)‐ene are components of the unsaponifiable fraction. The glycolipid fraction contains the pentacyclic triterpenoid tetrahydroxybacteriohopane.

Based on the thermoacidophilic growth conditions, the morphologic and physiological properties, and the nature of lipids, it can assumed that the new isolated strain belongs to the species Bacillus acidocaldarius.
Growth of a lactate dehydrogenase deficient mutant of bacillus stearothermophilus in continuous culture
Authors: Shama G.
Published: December 2004

A lactate dehydrogenase deficient strain of B. stearothermophilus, lld‐15, was outgrown by revertants to lactate production when cultivated in a chemostat at D = 0.25 h−1 on a rich complex medium at a sucrose concentration of 2.5% (w/v) but was maintained without reversion at this dilution rate when the sucrose concentration was only 0.5% (w/v). In batch culture the revertant showed characteristics which distinguished it both from B. stearothermophilus strains lld‐15 and NCA 1503.
Conversion of furfural into furfuryl alcohol by saccharomyces cervisiae 354
Authors: Diaz De Villegas M. E. , Villa P. , Guerra M. , Rodriguez E. , Redondo D. , Martinez A.
Published: December 2004

The influence of aeration, stirring conditions, and the addition of furfural on the yield and productivity of furfural – furfuryl alcohol bioconversion by the yeast strain Saccharomyces cerevisiae 354 was investigated.

The formation of furfuryl alcohol increases up to 32 hours of incubation corresponding to the addition of furfural, while the cell growth essentially ceased at 20 hours.

The conversion of furfural into furfuryl alcohol under anaerobic and low aeration conditions was 70% and the productivity 0.5g · 1−1 · h−1, when the final concentrationof of furfural amounted to 35 g · 1−1.
Multiple shoot formation and phenotypic changes of R0 regenerants in Hypericum perforatum L.
Authors: Čellárová E. , Kimáková K. , Brutovská R.
Published: December 2004

Seedings of Hypericum perforatum L. have produced multiple shoots on RM medium supplemented with 2.22 or 4.40 μM BAP. Regenerants were evaluated for variability in several morphological characteristics. A comparison with the control showed significant differences in fresh and dry matter and height of plants, but did not effect branching and the number of glands containing dianthrones.
Microbial transformation of furfural to furfuryl alcohol by saccharomyces cerevisiae
Authors: Villa G. P. , Bartroli R. , López R. , Guerra M. , Enrique M. , Peñas M. , Rodríquez E. , Redondo D. , Jglesias I. , Díaz M.
Published: December 2004

Biotransformation of furfural by Saccharomyces cerevisiae 354 was performed in a sugar cane molasses medium containing salts. The furfural added was rapidly reduced to furfuryl alcohol until a final addition of 3%, without inhibition in the cells growth. An efficient conversion of 96% was obtained by feeding 6 g · l−1 every 6 hours.
Production of Pleurotus ostreatus mushrooms on sugar cane agrowastes
Authors: Klibansky M. M. , Mansur M. , Gutierrez I. , González L.
Published: December 2004

The growth of different strains of Pleurotus spp. on sugar cane agrowastes was evaluated. Three hybrid strains with good production outcomes and yields exceeding 17% were selected. Strain 184 (P. ostreatus x P. pulmonarius) showed the best results.

Three spawn materials (wheat grain, millet grain and milled corn cob) at different spawning levels were tested and a significant influence was found. The obtained results were best explained in terms of total nitrogen content of the initial mixture (spawn + substrate), suggesting a probable nitrogen limited growth of the mushroom on sugar cane residues. A 10% millet grain spawn was found to be a reasonable compromise.

Productive responses decreased with an increase in bag's capacity (8–10–12 kg), even though the same diameter was maintained in order to avoid pronounced temperature profiles. Smaller bag's capacities (8–10 kg) were recommended.

It was also shown that the utilization of water hyacinth (Eichhornia crassipes) mixed 50/50 with sugar cane residues as substrate caused a twofold increase of crop responses, confirming the advantages of this substrate supplementation.

The obtained results identified sugar cane agrowastes as a feasible substrate for Pleurotus spp. production with yields and biological efficiencies comparable and to some extent better than others reported with conventional lignocellulosic residues such as cereal straw.
Screening and selection of bacteria with high amylolytic activity
Authors: Castro G. R. , Ferrero M. A. , Méndez B. S. , Sin¯eriz F.
Published: December 2004

515 microorganisms of the genus Bacillus which produce starch‐degrading enzymes were isolated from natural environments in the course of a screening programme. Treating the Bacillus strains on agar plates with iodine reagent for 30 seconds led to the selection of clones with increased amylolytic activity. This methods is very convenient for the screening of large numbers of amylolytic strains.
Dinitrophenol influences the rate and yield of Acetobacter methanolicus during the growth on glucose
Authors: Müller R. H. , Babel W.
Published: December 2004

Acetobacter methanolicuswas grown on glucose in the presence of dinitrophenol (DNP) under carbon/energy‐limited conditions. DNP affected both the growth yield and the growth rate (Dsh) at which the energy generation was shifted from a complete to an incomplete substrate oxidation by using the PQQ‐linked glucose dehydrogenase. The more the growth yield was decreased, the higher both the DNP concentration and the growth rate became. At about 0.53 mM DNP, growth was completely stopped. Dsh decreased from 0.21h−1in the absence of DNP to 0.175 h−1and 0.075 h−1in the presence of 0.2 mM and 0.4 mM DNP, respectively. The experimental data are discussed in terms of the limitations in the generation of energy and some stress situations which are exerted by the presence of the uncoupler.
Characterization of transgenic mice lineages. II. Transgenic mice expressing HBsAg particles and showing female sterility
Authors: Pérez A. , Castro F. O. , Martínez R. , Falcón V. , Baranovsky N. , Berlanga J. , Aguirre A. , Infante J. , Guillén I. , Aguilar A. , de la Fuente J.
Published: December 2004

The tissue specificity of the expression of the hepatitis B surface antigen (HBsAg) in transgenic mice was studied. Northern blot hybridization and electron microscopy of various tissues revealed the higher HBsAg transcription levels confined to the liver and kidney, and to a lesser extent to the spleen and intestines. In electron microscopic studies we found HBsAg particles in the serum of transgenic animals to be positive by ELISA to HBsAg. The expression of the transgene was localized in situ in the ovary, liver, kidney, and spleen of transgenic mice, employing a polyclonal antiserum directed against the HBsAg and conjugated with protein A‐gold. Surprisingly, F1 transgenic females from the CB‐104 line, expressing HBsAg in the serum, showed impaired fertility, although the ovarian function was not diminished. Normal off‐spring were obtained after cross embryo transfer between transgenic (Tg) females to non‐transgenic (Ntg) recipients or from Ntg embryos transferred to Tg recipients. We speculate that this phenomenon could be related to a disruption on a gene(s) somehow involved in the reproductive performance of the transgenic females.
Evaluation of the effects of a polyurethane carrier on the degeradation of chlorinated anilines by Pseudomonas acidovorans CA50
Authors: Loidl M. , Stockinger J. , Hinteregger C. , Streichsbier F.
Published: December 2004

A previously described model system for the treatment of harzardous chloroaniline‐containing waste waters using immobilized bacterial cells in a bioreactor was enhanced in its degradation efficiency. This was achieved by the substitution of the calcium alginate heads by an inert polyurethane (PU)‐carrier. The supply of chloroaniline‐polluted waste waters with the PU‐carrier (1.25% w/v) resulted in a distinct decrease of the pollutant concentrations in the solution due to the effects of adsorption. Nevertheless, the initially bound amounts of the chloroanilines were also degraded, which was proved by the chloride balance. In comparative batch‐degradation experiments with the Pseudomonas acidovorans strain CA50 with and without the addition of the PU‐carrier (1.25% v/w), respectively, the advantages of the PU‐supplied treatment system were demonstrated; among others a marked shortening of the degradation periods was achieved. The advantage of the PU‐carrier was also shown by using a bubble reactor. In this connection, it is particularly worth mentioning, that high degradation rates can be achieved for a long time even for strongly persistent pollutants.
Generation of rules for expert systems by statistical methods of fermentation data analysis
Authors: Guthke R. , Ludwig B.
Published: December 2004

Five new methods for determining the relations between kinetic data of fermentations are described and applied to an industrial antibotic fermentation process. The input data for these method are the elements of the distance matrix dij, which quantify the sum of the deviation squares between the time dependent kinetics x (t) of the fermentation runs i and j. For each measurable or calculable kinetic state variable, one n x n distance matrix must be calculated where n is the number of fermentation runs. All methods compare these distance matrices by statistical or graph‐theoretical approaches. The algorithms obtained are universally applicable if enough kinetic data are available, especially from more than 10 comparable fermentation runs. The algorithms were developed for the use in knowledge acquisition modules of expert systems.
The relationship between the microbial activity of the autochthonous microorganisms of pristine and contaminated soils and their potential for the degradation of mineral oil hydrocarbons
Authors: Miethe D. , Riis V. , Babel W.
Published: December 2004

The microbial activity of pristine and contaminated soils was investigated by measuring the following parameters: glucose induced respiration, dimethylsulphoxide reduction and the hydrolysis of fluorescein diacetate. The viable counts were determined by the plate count method.

The ability of the autochthonous microorganisms of the investigated soils to degrade diesel fuel was determined in a closed system on the basis of the oxygen consumption and by direct measurements of the hydrocarbon concentrations.

As expected, compost showed the highest microbial activity with regard to all three parameters, followed by the grassland and the arable soil samples which were also found to have high activity. However, soils that had been exposed to mineral oil for a long period of time showed significantly lower values.

Microorganisms from contaminated sites had a high degradation potential; few pristine soils reached similar turnover rates. The investigations showed that the level of the degradation of diesel fuel in pristine soils correlated with their microbial activity, but this correlation was not found in the investigated contaminated soils.
Construction of broad‐host‐range plasmids for the expression of heterologous genes in Acetobacter methanolicus B58
Authors: Föllner C. G. , Schröder R. , Babel W.
Published: December 2004

The construction of different plasmids reported here on the basis of a broad‐host‐range RSF1010 replicon allows an efficient expression of heterologous genes in the acidophilic methanol‐assimilating bacterium Acetobacter methanolicus B58.

The promoter‐probe vector pRS201 was used for the identification and isolation of the promoter containing sequences derived from the DNA of the Acetobacter phage Acm1. Further, this plasmid was coupled with the Escherichia coli promoters tac and pr creating the expression vectors pRS201tac and pRS201pr, respectively. After the insertion of the chloramphenicol acetyltransferase (cat) gene of the cloned promoters downstream, the chloramphenicol acetyltransferase (CAT) was determined in a cell‐free extract of both E. coli and A. methanolicus.

Using E. coli promoters as well as promoters of the Acetobacter phage Acm1 arranged in tandem with the promoters of the heterologous genes to be expressed, the pectat lyase gene (ptlB) of Erwinia carotovora and the threonine A gene (thrA) of E. coli were successfully expressed in A. methanolicus.

The stability of recombinant plasmids under various conditions in A. methanolicus strains was tested using antibiotic‐free media.
Stability studies of thermophilic anaerobic sludges under suboptimal feeding conditions and temperatures
Authors: Obaya M. C. , Valdés E. , Ramos J.
Published: December 2004

The behaviour of thermophilic anaerobic sludge from the UASB process was investigated under suboptimal conditions.

Stability studies, carried out during the normal operation of the reactors, showed that a short‐term decrease in temperature had no influence on the behaviour of the process.

Nevertheless, interruptions in feeding and a long‐term decrease in temperatures can produce very drastic effects on the stability of the system.
Granulation of digested sewage sludge in mesophilic UASB reactors treating distillery waste waters from sugar cane molasses
Authors: Ramos J. , Obaya M. C. , Valdes E. , Villa P. , Eng F.
Published: December 2004

Five 4.02‐1 UASB (Upflow Anaerobic Sludge Blanket) reactors were continuously operated at 30°C under different hydrodynamic regimes for more than 120 days. The effect of the upflow liquid velocity (ULV) over the range of 0.25 to 2.0 m/h on the biological characteristics of the granules formed by treating vinasses (waste water of alcohol distilleries) from sugar cane molasses was investigated constantly maintaining the volumetric loading rate (VLR) (8 g COD/l · d). Granular sludge was found at all the ULV tested. The size, shape, etc., of the granules indicated that the ULV had a considerable effect on the sludge cultivated in this type of system, thereby acting as a selection process for the biomass. The best results in relation to the time of appearance, size, shape, consistence, stability, composition, and the accumulation were observed in the ULV range between 0.25 and 0.5 m/h.

Microscopic studies of the granules using optical and epifluorescence microscopes and the scanning electron micrograph (SEM) showed a heterogeneous biomass and revealed the cell characteristics.
Monoterpenol glycosides in plants and their biotechnological transformation
Authors: Vasserot Y. , Arnaud A. , Galzy P.
Published: December 2004

The present paper reviews the different monoterpenols and monoterpene polyols identified in the glycoside form in the plant kingdom. The glycosidic moieties involved are also considered. The natural pathways for the synthesis and hydrolysis of these monoterpene glycosides and the different hypothesis concerning their metabolism are discussed. The present state of different projects for the biotechnological transformation of these aromatic precursor compounds is reported.
Fermentation kinetics of free and immobilized Penicillium raistrickii able perform the 15α‐hydroxylation of 13‐ethyl‐gon‐4‐ene‐3,17‐dione
Authors: Schlosser D. , Irrgang S. , Schmauder H.‐P.
Published: December 2004

Growing Penicillium raistrickii i 477 cells immobilized by microencapsulation, entrapment in calcium alginate beads and photopolymerization were used for the 15α‐hydroxylation of 13‐ethyl‐gon‐4‐en‐3,17‐dione (I) to 15α‐hydroxy‐13‐ethyl‐gon‐4‐en‐3,17‐dione (II). The immobilized cells had lower maximum specific growth rates and yield coefficients when cultivated on the carbon source glucose than the non‐immobilized cells, which leads to lower volumetric productivities than the use of nonimmobilized cells. However, the cells immobilized by microencapsulation and calcium alginate entrapment showed a specific productivity equal to that of the respective non‐immobilized cells based on product formation per dry biomass and time. Photommobilized cells were not able to grow in the presence of the steroid because the substrate concentrations within the polymer reached inhibiting amounts for growth and product formation. In the absence of the steroid, the growing photoimmobilized cells showed a prolonged lag‐phase in comparison with the free cells.
The effects of xylanase type enzymes on the different layers of birch wood ORGANOSOLV pulp fibre walls
Authors: Leite M. , Eremeeva T. , Treimanis A. , Egle V. , Bykova T. , Purina L. , Viesturs U.
Published: December 2004

Some effects of the xylanase treatment on the separate birch ORGANOSOLV pulp fibre wall morphological layers were examined. These investigations were focused on the outer layers, i.e. the primary wall (P) and the outer layer of the secondary wall (S1), as well as the central layers, i.e. the central layer of the secondary wall (S2) and the tertiary wall (T). Step by step, the fractionation of the pulp components in the polar solvents N,N‐dimethylformamide (DMFA), dimethylsulphoxide (DMSO) and DMSO/H3PO4 was used as a mild technique for the isolation of the lignin‐carbohydrate complexes. The different residual amounts of lignin and hemicelluloses in the outer and central pulp fibre wall layers as well as the different lignin‐hemicellulose ratios were determined. The size‐exclusion chromatographical (SEC) analysis showed a higher initial lignin content in the region of the high molecular mass (MM) fibre wall fraction extracted with “DMSO/H3PO4” than the outer cell wall layers. In the central layers, the amounts of soluble lignin (calculated on the mass of total dissolved substance) were approximately the same for all the three solvents.

The xylanase treatment brought the most considerable changes in the high MM part of the residual lignin (the lignin carbohydrate complex). This was true for both the P‐S1 and S2‐T layers. The careful brightness comparison of the outer and central fractions after the X‐E‐P‐P bleaching sequence showed a surprisingly low bleachability of the outer layer fraction. The xylanase action depended on the composition of the lignin‐carbohydrate complex (LCC) and the extent of the maintenance of the outer layers during the pulping process.
Characterization of casein peptones by HPLC profiles and microbiological growth parameters
Authors: Reissbrodt R. , Beer W. , Claus H. , Müller R.
Published: December 2004

Thirty six pancreatic casein peptones from various producers were analyzed by HPLC and by microbiological growth tests. The data were compared by using the principal coordinate analysis and simple mathematical tests. The Proteose peptone quotient, PQ1, determined by the growth of Escherichia coli, separated these casein peptones into three groups, depending on their suitability as nutrients compared to Proteose peptone as a standard. These groups corresponded to the HPLC patterns, characterized by the specific peaks of polypeptides, peptides and amino acids, respectively. The peaks of the high‐molecular weight polypeptides were negatively correlated with the growth parameters. The peptides of a low molecular weight promoted the growth of Staphylococcus aureus with and without the exhaustion of usable N compounds and in the presence and absence of glucose (PQ2 and PQ3). The colony sizes correlated weakly with certain peaks only. HPLC patterns, thus, seem to be useful for the characterization of casein peptones for the standardization of nutrient media as well as for special applications.
Production of rifamycin B and SV by free and immobilized cells of Amycolatopsis mediterranei
Authors: Farid M. A. , El‐Diwany A. I. , El‐Enshasy H. A. , Abu‐Shady M. R.
Published: December 2004

The effect of growth conditions (incubation time, inoculum size, initial pH value) and some nutrient concentrations on the growth and rifamycin B and SV production by free and immobilized cells of Amycolatopsis mediterranei CBS 42 575 was studied. In alginate beads, the immobilized cells behaved like the free cells, but a pronounced difference was observed in antibiotic production and cell growth. The rifamycin production by the immobilized cells was higher than that obtained by the free cells. The immobilized cells were also reused repeatedly for six batch cultivations with a fresh medium charged into flasks at the beginning of each batch. It was found that the immobilized cells were stable, and the rifamycin yield was almost constant during the first three batches and then decreased.
Physiological restriction of the L‐lactic acid production by Rhizopus arrhizus
Authors: Rosenberg M. , Krišofíková L.
Published: December 2004

The influence of basic physiological factors on the quality of inocula and L(+)‐lactic acid production by Rhizopus arrhizus CCM 81 09 were studied.

The most effective preparation of the spores (5 × 107 spores/ml) and subsequent good lactate production was achieved on the agar medium with soil extract and malt agar. The optimum initial amount of active spores for inoculation was 103–104 spores/ml. The preparation of inoculum required intensive stirring with lower aeration and pH maintained in the range from 4.8 to 6.0 by the addition of CaCO3. The maximum yield of lactic acid production was achieved by using 5% (v/v) of 24‐h‐old inoculum. The intensity of lactic acid production in the inoculum was proportional to its production in the subsequent steps of fermentation and can be used as a fast control of the physiological state of the producers.
A new version of an in situ sampling system for bioprocess analysis
Authors: Hilmer J.‐M. , Scheper Th.
Published: December 2004

In this article, attention is focussed on an on‐line sampling device for bioreactors and its characterization regarding sterility and response time. The integration of this device into analytical systems for biotechnology (FIA with biosensors) resulted in on‐line analysis systems for bioprocess control. The new ESIP version of an in situ sampling system for bioprocess analysis produced by the EPPENDORF‐NETHELER‐HINZ GmbH, Germany, had a short response time of 8 min (99%), which was determined by means of conductivity measurement after an increase of the medium conductivity due to the gradual addition of KCl. Effectiveness and reliability of the module were tested by bubble point measurement resulting in a bubble point pressure of 2.1 bars. The sampling probe was tested successfully for use in a broad variety of microorganisms and cultivations.
Penicillium citrinum protoplasts: Preparation, regeneration and lipolytic activity of regenerants
Authors: Maliszewska I. H. , Zboińska E. M.
Published: December 2004

The conditions for an optimum formation of protoplasts from mycelium of Pencillium citrinum, which produces extracellular lipase, were examined. The best results were achieved using Novozyme 234 in combination with β‐glucuronidase. Chitinase or β‐glucuronidase alone were not able to produce protoplasts under the given conditions. For the regeneration frequency, the type of osmotic stabilizer was important. The highest regeneration frequency (84.6% protoplasts) was achieved by using 0.6 M KCl as an osmotic stabilizer. Some regenerants were more effective in producing lipase than the parent. In particular, strain no. P‐8 showed a three times higher lipolytic activity than the parent strain, but this high enzyme activity was unstable after subculture.
Relationship between citric acid and extracellular acid phosphatase production by Aspergillus niger
Authors: Fiedurek J. , Pluta B. , Szczodrak J. , Jamroz J.
Published: December 2004

Optimum conditions for citric acid production by Aspergillus niger in submerged culture were established. Some correlation was found between the ability of the fungus to produce citric acid and its capability to accumulate extracellular acid phosphatase. Mutagenization and passage on sodium citrate (10–25%) medium gave rise to eleven A. niger strains able to grow when the concentration was 25%. Two mutants showed an increase in citric acid production (8.8–25.7%), accompanied by the highest activity of acid phosphatase (43.1–46.6%).
Substrate specificity of laccase from Lentinus edodes
Authors: D'Annibale A. , Celletti D. , Felici M. , Di Mattia E. , Giovannozzi‐Sermanni G.
Published: December 2004

In previous studies, the white‐rot basidiomycete Lentinus edodes, strain SC‐495, was proved to be a “selective” lignin degrader and its extracellular crude preparations arising from solid‐state cultures were successfully employed in biopulping experiments on annual plants. This fungus produced extracellular laccase as the predominant phenoloxidase when growing in solid‐state fermentation on corn stalks. Laccase from this strain was purified and partially characterized, as an initial approach towards the study of its ligninolytic complex. Laccase was purified 69.6‐fold by anion‐exchange chromatography and two affinity‐chromatography steps with an overall yield of 7.45%. The native enzyme exhibited a molecular mass of 74 kDa, an isoelectric point of 3.42 and a carbohydrate content of 7.5%. The absorption spectrum of laccase showed a maximum at 605 nm, typical of blue‐copper oxidases. The optimum pH and temperature for the activity of laccase were 4.0–4.2 and 50°C, respectively. Kinetic experiments, performed with a wide range of phenolic compounds, showed that the reaction rate and the substrate affinity greatly varied depending on the nature of substituents and their reciprocal positions on the aromatic ring. In particular, the enzyme showed high affinity to phenolic compounds bearing methoxyl or methyl groups, but no affinity to those bearing the nitro group directly attached to the benzene ring, nor to non‐phenolic lignin‐related compounds, such as trans‐cinnamic acid or 3,4‐dimethoxycinnamic acid. The huge differences in terms of reactivity of the enzyme towards phenolic compounds suggests that a preliminary systematic screening should be advisable when using laccase in effluent treatment applications.
Application of statistical selection procedures for selecting the mutant with the highest enzyme activity from a set of mutants of the species Aspergillus niger
Authors: Römisch U. , Gargova S.
Published: December 2004

The enzyme Glucoamylase [1,4‐α‐D‐glucan‐glucohydrolase EC 3.2.1.3] is very important for the food industry. It is used for producing glucose, ethanol and beer, as well as in technological processes that require the decomposition of starch. Eight mutants of the species Aspergillus niger are evaluated and tested with respect to their production of Glucoamylase and proved to be suitable. The task is to find the mutant showing the highest enzyme activity with a given precision. Conventionally, this kind of multiple decision problem is handled by the analysis of variance (Model I), which tests the homogeneity of the population means, but in this case the results do not supply the desired information. Provided that the enzyme activities of the mutants are different, selection procedures can be used to choose the mutant with the “best” or at least a “good” level of activity.

In this paper, a short methodical summary about the two classes of selection procedures is given, i.e. the indifference zone (and d‐correct) procedures and the subset procedures. By the example of the selection of a mutant with high enzyme activity the planning of experiments is shown. Depending on suppositions about the variances, different selection rules are applied. Starting with the subset procedure of GUPTA, the number of mutants is reduced to seven. The following application of the d‐correct procedures of BECHHOFER, DUNNETT and SOBEL allow us to calculate the necessary sample size of n = 49. Then the mutant whose sample has the largest mean will be selected as a “good” one with a given precision of d = 4 [u/l] and a probability of correct selection of (1–β) = 0.9

This application is result of a cooperation between the Dept. of Food of the Technical University, Berlin, and the Dept. of Biotechnology of the Higher Institute of Food and Flavour Industry, Plovdiv, sponsored by the DAAD andthe TU Berlin.
Characteristics of a microbial assay for the detection of halogenated hydrocarbons using cells of an actinomycete‐like organism as a biological component
Authors: Peter J. , Buchinger W. , Karner F. , Hampel W.
Published: December 2004

Cells of an Actinomycete‐like bacterium, strain GJ70, with the ability to degrade several haloalkanes were used as a biological component in a discontinuous microbial bioassay for the detection of 1,3‐dichloropropene and 1,2‐dibromoethane in water. The cells were entrapped in different matrices such as calcium alginate, carrageenan, chitosan, polyacrylamide‐hydrazide and chitosan‐carboxy‐methyl cellulose; the specific dehalogenating activity of the immobilized cells to a stirred sample solution and by the use of an ion selective electrode (ISE) for the quantification of enzymatically released halogen ions, the concentration of halogenated hydrocarbons could be estimated by determining the change of electrode potential within a period of 5 min. The detection limits for 1,3‐dichloropropene and 1,2‐dibromoethane were below 100 μg/l and 25 μg/l, respectively; the relative standard deviation was < 10%. In addition, several chlorinated and brominated hgydrocarbons were converted by the bacterial cells at a reduced rate e.g. 1, 2‐dibromopropane, 1‐bromoethane, 1,5‐dichloropentane, etc. Moreover, temperatures of between 20 and 40%C did not affect the enzymatic activity of the cells, and a pH of between at 5 and 9 had little influence. Several organic substances and non‐metabolizable compounds did not affect the conversion, whereas some heavy metal ions acted as inhibitors.
Levan production by Zymomonas mobilis cells. Attached to plaited spheres
Authors: Bekers M. , Ventina E. , Laukevics J. , Kaminska E. , Upite D. , Vigants A.
Published: December 2004

In this work, an immobilization method for polymer‐levan production by a non‐flocculating Z mobilis culture was developed. The extent of cell attachment to the stainless steel wire surface, culture growth and product synthesis were described. It was established that during short‐term passive immobilization of non‐flocculation Z mobilis cells on a stainless steel wire surface, sufficient amounts of biomass for proper levan and ethano fermentation could not be obtained. Adherence of cells was improved by pressing the paste‐like biomass within stainless steel spheres knitted from wire with subsequent dehydration. Biomass fixed in metal spheres was used for repeated batch fermentation of levan. The activation period of cells within wire spheres (WS) was 48 h in duration. During this time, cell growth stabilized at production levels of ethanol and levan of Qeth = 1.238 g/l × h and qeth = 0.47 g/l × h; Qeth = 0.526 g/l × h and qeth = 0.20 g/l × h. Five stable fermentation cycles were realized using one wire sphere inoculum, and maintaining a stable ratio of 2.4 of biomass suspended in the medium to biomass fixed in the sphere. Using fixed Z mobilis biomass in the WS, the total amount of inoculum could be reduced for batch fermentation. Large plaited wire spheres with biomass may have potential in fermentation in viscous systems, including levan production.
Growth of Paenibacillus larvae, the causative agent of American foulbrood in honey bees and Bacillus popilliae, the causative agent of milky disease in beetle larvae in lepidopteran cell cultures
Authors: Steinkraus K. H. , Mortlock R. P. , Granados R. R. , McKenna K. A. , Villani M. G. , Robbins P. S.
Published: December 2004

TNM‐FH Lepidopteran insect cell culture medium containing 10% fetal bovine serum (FBS), while allowing limited vegetative growth of Paenibacillus larvae (wild‐type strain), the causative agent of American foulbrood, contained no viable vegetative cells upon subculture, nor were any heat resistant spores produced in this medium alone. However, TNM‐FH medium cotaining embryonic or midgut cells from Trichoplusia ni, hemocytes from Estigmene acrea, ovarian and embryonic cells from Spodoptera frugiperda, embryonic cells from Plutella xylostella, Spodoptera exigua and Pseudaletia unipuncta or ovarian cells from Lymantria dispar, supported both heavy vegetative cell growth and moderate production of heat resistant spores. EX‐CELL 405 serum‐free insect cell culture medium alone appeared to contain the appropriate nutrients required for both vegetative growth and sporulation of P. larvae. However, in the presence of embryonic cells from T. ni, limited vegetative growth occurred and the P. larvae cells appeared to die off. This was confirmed by the fact that no colony growth occurred upon subculture, nor were any heat resistant spores detected. This was true also in the presence of fat body cells from T. ni, except that a limited number of spores (4,000/ml) were detected in the form of cology‐forming units (CFU) on plates following heating to 80°C for 20 minutes. In a parallel study with a wild‐type strain of Bacillus popilliae, vegetative cells grew only in TNM‐FH medium in the presence of mid‐gut BTI‐Tn‐MG and ovarian (Tn‐368) cells of T. ni. No heat resistant spores, however, were detected in any of the cultures. When BTI‐Tn‐MG and Tn‐368 cells were further challenged with four variant cultures of B. popilliae, vegetative growth and limited sporulation were achieved. The BTI‐Tn‐MG cell line in TNM‐FH medium produced as many as 12,000 spores/ml after 21 days in culture.
Influence of some physicochemical factors on the viscosity of aqueous levan solutions of Zymomonas mobilis
Authors: Vina I. , Karsakevich A. , Gonta S. , Linde R. , Bekers M.
Published: December 2004

Zymomonas mobilis strain 113 “S” produces levan – an extracellular, viscous, biologically active, non‐toxic fructose polymer with a unique structure and extraordinary properties. This polysaccharide was isolated at two different degrees of purity by alcohol precipitation from aqueous solutions and was characterized with respect to some rheological properties and stability of viscous solutions.

The effects of temperature, pH and salt concentration on the viscosity of 1–3% levan solutions were examined. The viscosity of levan solutions was found to be quite stable and reversible at room temperature over a wide range of pH from 4 to 11. The viscosity was slightly affected by increased salt concentration. Levan solutions were rather stable at high temperatures (up to 70°C, 1 h, pH 6), where the viscosity could be almost completerly restored (up to 80–100%). Therefore, the degradation of the polymer structure under these conditions is probably insignificant. Temperatures of 70–100°C with a pH of less than 3.5 caused irreversible degradation of the levan structure.

The above‐mentioned properties of levan, obtained from Zymomonas mobilis 113 “S”, demonstrated the potential for the development of various therapeutic forms of pharmacologically‐active levan and their application in medicine as well as in the food and other industries.
Characterization of microbial endo‐β‐glucanase immobilized in alginate beads
Authors: Busto M. D. , Ortega N. , Perez‐Mateos M.
Published: December 2004

Endo‐β‐glucanase (endo‐β‐1,4‐glucano‐glucanase EC 3.2.1.4), isolated from Trichoderma reesei, was immobilized in calcium alginate beads, retaining 75% of its original activity. The polyanionic moiety surrounding the immobilized enzyme displaced the pH‐activity profile to alkaline regions with respect to that of the free enzyme. The enzyme was inhibited by carboxymethylcellulose, but this inhibition appeared to be decreased by immobilizatíon. The enzyme immobilized in alginate beads showed a Km value (1.02% w/v) lower than that of the enzyme (1.31%). The apparent Vmax of immobilized cellulase preparations (238.3 μmol glucose/ml × h) decreased by a factor of 0.59 with respect to that of the soluble enzyme. The optimum temperature (60°C) of the free and entrapped enzymes remained unaltered. In contrast, the half‐life of the endoglucanase immobilized in calciumalginate beads was 4.6 h at 55°C and 5.4 h at 60°C, while that of the free enzyme was 3.0 h at 55°C and 1.2 h at 60°C. A technological application of the immobilized enzymes was tested using wheat straw as a source of fermentable sugars. The hydrolytic degradation of straw, by means of a crude extract of free and immobilized cellulases and β‐glucosidase, released a large amount of reducing sugars from wheat straw after 48 h (between 250–720 mg glucose/g straw), carrying out more than a 90% saccharification. A mixture of immobilized β‐glucosidase and free cellulases maintained 80% of the activity of the soluble counterparts, and the co‐immobilization of both types of enzymes reduced by hydrolytic efficiency to half.
Performance of airlift bioreactors in the cultivation of some antibiotic producing microorganisms
Authors: Gavrilescu M. , Roman R. V.
Published: December 2004

The specific aspects of airlift reactors emphasizing their function relevance to particular application as bioreactors are presented.

The two main groups of airlift reactors – external‐loop and concentric‐tube reactors – were investigated on a pilot‐plant scale with regard to their performance during the cultivation of unicellular and filamentous microorganisms which produce Bacitracin, Cephalosporin C and Nystatin. Some results were compared to those obtained in conventional stirred tank bioreactors. The comparison was carried out based on physical properties (oxygen transfer rate (OTR), volumetric mass transfer coefficient (kLa) and efficiency of oxygen transfer (E)), cell mass, productivity and substrate consumption, secondary metabolite production, and efficiency of the product formation with regard to the specific power input.

It was shown that B. licheniformis, C. acremonium and S. noursei fermentations occurred similarly to those performed in stirred vessels, proving that the capacity of the airlift bioreactors surpassed the problems which arise from the morphology and rheology of the broths. From the chemical engineering point of view, it was obvious that the primary tasks of a bioreactor (uniform distribution of microorganisms and nutrients over the entire fermenter volume, appropriate supply of biomass with nutrients and oxygen) were fulfilled by the airlift bioreactors tested. In addition, the efficiency of oxygen transfer (OTR referred to power input) in the airlift fermenters proved to be about 38% higher than in the stirred tank bioreactors (expressed as average values), while the sorption efficiency (OTR referred to antibiotic production) was found to be 22% greater in the airlift system than in an STR.

Therefore, the biosyntheses were performed with about a 30–40% increase in energy efficiency and energy savings compared to the conventional system.

Moreover, the lack of mechanical devices in the airlift system provides greater safety and a gentler environment for the cultivation of microorganisms.