bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth efficiency of thielavia terrestris mycelial structures
Authors: Gromosova E. N. , Fomina M. A. , Podgorsky V. S. , Leite M. P. , Zeltina M. O. , Shvinka Y. E.
Published: December 2004

The growth energetic efficiency (η) of two mycelial forms of Thielavia terrestris (pellets and diffused form) was studied by different methods. η Values determined by the pulse method are similar for the two forms, but the values determined by C balance for pellets were lower than those for diffused mycelium. These balance data prove that pellets yield more extracellular products than the diffused mycelium form, which is also confirmed by experimental data for different amounts of carbon in the culture fluid.

Growth efficiency can be determined by various methods based on the principles of mass and energy balance. The estimates most frequently used are the biomass and substrate balances. However, growth efficiency determination according to oxygen balance (particularly by the pulse method) is simpler and more accurate; as it makes possible the immediate fixation of changes in the physiological condition of microorganisms and the determination of complex substrate utilization efficiency [1]. Earlier the possible use of this method for evaluating the growth efficiency of heterotrophic bacteria [2], hyphalic and yeast forms of microscopic fungi [3] was shown. The aim of the present study is the comparative investigation of the growth efficiency of two mycelial structures (hyphalic and pellets) by different methods as well as by pulse additions.
Nitrogen – a guide element in the bioconversion of lignocellulosics
Authors: Weichert D. , Schröouter H.
Published: December 2004

Several balanced experiments of protein enrichment have shown that if ammonia is the sole N source in the bioconversion of lignocellulosics, significant data on the process can either be received from the N consumption determined, or from fixed organic nitrogen.

Nitrogen can be a guide element for such data as cell biomass, utilized substrate, degree of bioconversion, specific substrate consumption coefficient, crude protein and crude protein yield, which are all necessary for the classification of fungi and substrates as well as for process characterization and optimization.
Kinetic analysis and modelling of streptokinase fermentation
Authors: Stuebner K. , Boschke E. , Wolf K.‐H. , Langer J.
Published: December 2004

The kinetics based on the MONOD conception of anaerobic, discontinuous, isothermal, isobaric fermentation producing a special protein in secondary metabolism is studied.

The kinetic analysis results in a growth limitation by the primary product which shows a sigmoidal behaviour, a lineary correlation between the specific substrate degradation and the specific rate of formation lactic acid and a lineary correlation in a good approximation between the formation of proteins and substrate degradation.

In this study a process model with coupled differential equations is provided. Kinetic and stoichiometric coefficients are determined.
Formation of ethanol and higher alcohols by immobilized zymomonas mobilis in continuous culture
Authors: Oaxaca V. A. , Jones L. P.
Published: December 2004

Cells of Zymomonas mobilis ATCC 10988 were immobilized in 1.5% calcium alginate and packed in a column bioreactor for a series of fermentations utilizing 10.0% glucose media with the addition of one of the following amino acids or keto acids: L‐leucine, L‐isoleucine, L‐valine, α‐ketoisocaproic acid, α‐ketobutyric acid, or α‐ketoisovaleric acid. This was done in order to study the rates of production of higher alcohols during ethanolic fermentations at varying dilution rates while under the influence of amino acids or keto acids.

Results indicate that the EHRLICH mechanism is operative in Zymomonas sp. α‐Ketobutyrate enhanced the production of n‐propanol and act‐amyl alcohol. α‐Ketoisocaproic acid stimulated the production of isoamyl alcohol. α‐Ketoisovaleric acid increased the levels of isobutanol. The amino acids also gave rise to their corresponding alcohols but to a far lesser degree than did the keto acids. During high glucose utilization, ethanol yields ranged from 87% to 94% of theoretical with productivity ranging from 60.08 g/l/h in one fermentation (at a dilution rate of 1.35 h−1) to 70.42 g/l/h in another (at a dilution rate of 1.58 h−1). At dilution rates of 1.58 h−1, higher alcohol productivity rose to as high as 4,313 mg/l/h in the presence of α‐ketoisocaproic acid, 1,734.49 mg/l/h using α‐ketoisovaleric acid, and 1,618.05 mg/l/h in α‐ketobutyric acid. The concomitant production of ethanol and higher alcohols in all of the fermentations indicates that glucose is required for the production of the higher alcohols from their corresponding amino acids or keto acids.
Laboratory glass fermenter on the basis of the airlift principle
Authors: Schiemenz E. , Wendlandt K.‐D. , Mirschel G. , Simon D.
Published: December 2004

A 1.5‐1 minifermenter consisting of RASOTHERM glass on the basis of the airlift principle was constructed and tested in the Institute of Biotechnology.

The development of this fermenter bridged the gap between shake flasks and lab‐scale fermenters and provided a possibility for the continuous cultivation of extremely halophilic bacteria. It was demonstrated that the fermenter can be used for cultivating bacteria that are sensitive to shear stress. It can also be recommended for purposes of cultivation of plant and animal cells because of this advantage and the possibility of this fermenter to be sterilized.
Biotransformations of industrial use
Authors: Kieslich K.
Published: December 2004

Biotransformations represent a useful tool for the production of various chemical compounds because of their main advantages: attack of non‐activated positions, regio, stereo and enantio‐selectivity, and the mild reaction conditions.

Organic chemistry can use these advantages in various enzymatic type reactions.

One of the most interesting and promising groups of these biotransformations are the various oxidative reactions.

The following article intends to give a short insight in the present state of this part of the broad field of biotransformations.

Examples of technically interesting processes, preferably results of newer developments, should illustrate

the variety of enzymatical oxidative reactions used.

the various structures of educts for aimed oxidative modifications and.

the application in the pharmaceutical, food and chemical industries.
Isolation of auxotrophic mutants from acetobacter methanolicus MB 58
Authors: Föllner C. , Babel W.
Published: December 2004

The lysine content of the biomass of the acidophilic facultatively methylotrophic bacterium Acetobacter methanolicus MB 58 was increased by genetic manipulations.

A homoserine auxotroph, MB 58.196, and a threonine auxotroph, MB 58.195, were obtained from Acetobacter methanolicus MB 58 by N‐methyl‐N′‐nitro‐N‐nitrosoguanidine treatment.

Investigations of enzyme activities revealed that the homoserine auxotroph lacks homoserine dehydrogenase activity, and the threonine auxotroph lacks homoserine kinase activity.

Concerning the lysine‐producing ability, only the homoserine auxotrophic mutant accumulates lysine in the intracellular pool. The intracellular lysine content of this mutant was increased 40‐fold.

An excretion of amino acids into the medium was not detected. A homoserine resistant mutant, MB 58.196.10, isolated from MB 58.196 by UV‐irradiation, was able to excrete lysine. About 95% of free lysine were found in the culture medium. Altogether, the free lysine concentration was increased 800‐fold in comparison to the wild‐type strain.

By these genetic manipulations the total lysine concentration of MB 58.196 was increased to 2.7% and of MB 58.196.10 to 56% in comparison to the wild‐type strain.
High performance bacterial fermentation process with two gaseous substrates
Authors: Pöhland H.‐D. , Hühn H. J. , Klarmann H. , Prause M. , Soyez K.
Published: December 2004

Two methane utilizing bacteria strains, GB 21 and WSB 874, were cultivated with methane as sole carbon and energy source in a submerged continuous fermentation process. The aim of the investigations was to reach high biomass concentrations (>25 g BDM ·kg−1 medium) and high productivities (>3 g BDM · kg−1 · h−1). A precondition for the high‐performance fermentation process was to ensure a transfer rate of methane and oxygen in quantities required by the microorganisms. For this purposes a high performance stirred pressure fermenter was used. The fermentation process is characterized by the transfer of two gaseous substrates. In order to develop a technical process it was necessary to investigate both the correlations between the two gases and the productivity of the fermentation process and the influence of system pressure on the microorganisms.

Within a pressure range of up to 0.7 MPa a biomass concentration of up to 50 g BDM · kg−1 medium and a productivity of up to 9 g BDM · kg−1 · h−1 was reached in a continuously running fermentation process under nonsterile conditions. Under these fermentation conditions the microbial population consisted of a dominating main culture GB 21 or WSB 874, respectively, and an accompanying flora (type II). The microbial population was very stable in its composition during the fermentation process running continuously for weeks and months.
“Ecological biotechnology” – the new dimension in technology
Authors: Moser A.
Published: December 2004

Ecological restructuring of all areas is the most essential action needed for the future of our cultures on earth.

This paper intends to clarify how human technology activities can be embedded in the cycles of the biosphere.A new quality of life will be maintainable by this concept of ecologically sustainable technology.The background of this innovation is explained in more detail and the fundamentals are eluciatated comprehensively. A series of principles of general validity are derived from the study of ecosystems in biosphere, which are to be transferred to technologies. This will result in the new technology paradigm of “ecologic process engineering” which is part of a new paradigm in sciences.
Hollow fibre modules as membrane reactor in biocatalysis
Authors: Luther H. , Hirsch S. , Schuster E. , Weber E.
Published: December 2004

As shown in the case of the enzymatic cleavage of Penicillin G by Penicillin acylase hollow fibre modules of the type MLW (molecular separation value of 10,000 Dalton) produced for blood dialysis are also suitable as membrane reactor.

The enzymes physically bound in the hollow fibre allow a reproducible reaction rate and are characterized by an acceptable stability.

The studies indicate an operating stability which makes possible low production costs of amino penicillin acid.
Molecular cloning of the gene, expression in E. coli and purification of the thermus aquaticus DNA polymerase I
Authors: Lleonart R. , Campos M. , Suáarez A. , Vaźquez R. , de la Fuente J. , Herrera L.
Published: December 2004

The Thermus aquaticus DNA Polymerase I gene was isolated by using standard recombinant DNA techniques and cloned into an E. coli vector in front of the lac promoter. E. coli cultures produced thermostable polymerase when induced with the analog IPTG. A purification procedure is shown which renders an enzymatic preparation suitable for PCR reactions.
Effect of different nitrogen and carbon sources on the proteolytic activity
Authors: Ibañez A. M. , Altuna B. , Díaz de Villegas M. E.
Published: December 2004

Two‐three fold increases in the levels of proteolytic activities in one strain of Bacillus licheniformis (R1‐8) were obtained when changes in the nature of the nitrogen source (food and fodder yeast instead of soybean meal) and in the amount of invert sugars in the culture medium were performed.
Nutritional conditions for the germination of streptomyces galbus 5ME‐13 spores
Authors: Sengupta S. , Paul A. K.
Published: December 2004

The nutritional conditions for the germination of spores of Streptomyces galbus 5ME‐13 were determined under laboratory conditions. The germination of the spores was intiated by the emergence of 1–2 germ tubes after the second hour of incubation and attained its maximum at the sixth hour. This was accompanied by a steady rise in the optical density of the germinating spore suspension. A malt‐extract yeast‐extract medium was found to be the best medium for the germination of the spores.

Glycerol as the sole source of carbon was the best supporter for spore germination while, as N source, L‐alanine was preferred. The optimum pH and temperature for spore germination were 7.2 and 30°C, respectively.
Cellulase secretion by immobilized protoplasts of Trichoderma reesei
Authors: Marinova D. N. , Atev A. P.
Published: December 2004

Protoplasts from Trichoderma reesei were immobilized in alginate and induced to produce cellulase (endoglucanase and β‐glucosidase) enzymes. The specific activities of the synthesized enzymes were higher in immobilized protoplasts than in both free and immobilized mycelia.

Immobilized protoplasts show an enhanced rate of exocellular β‐glucosidase production compared to intact mycelia due to the lack of cell wall. The ratio of the exocellular/intracellular β‐glucosidase was 5.9 for immobilized protoplasts and 0.32 for free mycelia.
Transformation of D‐xylose by sporobolomyces lactosus
Authors: Proksa B. , Sláviková E. , Uhrínová S.
Published: December 2004

The new yeast species, Sporobolomyces lactosus, transformed D‐xylose into a mixture of disaccharides. Hydrolysis of this mixture yielded D‐glucose only. The main component of disaccharide mixture was α,α‐trehalose.
Some biological characteristics of the casing soil and their effect during Agaricus bisporus fructification
Authors: Cochet N. , Gillman A. , Lebeault J.‐M.
Published: December 2004

The intent of this work was to study the biological and biochemical aspects of the casing soil role on every stage of the A. bisporus fructification. We reported the development of mycelial thick threads of A. bisporus in the casing soil.

Moreover, we pointed out the protective role of the calcium salts crystals surrounding the hyphae during the incubation stage. On the electron‐micrographies, the mycelial aggregates were surrounded by bacteria, and this bacterial growth seemed to be related to the calcium salts crystals disappearance.

The positive influence of A. bisporus upon bacterial growth, and vice versal, was confirmed with PETRI dish cultures.
Studies on root nodules of leguminous plants bioproduction of indole acetic acid by a Rhizobium sp. from a twiner Clitoria ternatea L.
Authors: Roy M. , Basu P. S.
Published: December 2004

The Rhizobium sp. isolated from the root nodules of Clitoria ternatea L., a leguminous twiner, produced a high amount of IAA (16.4 μg/ml) from tryptophan in an unsupplemented basal medium. The production of IAA started simultaneously with the growth and had no different growth and production phase. The growth and production were parallel and increased up to 45–50 h. The IAA production by the Rhizobium sp. was increased by 520% when the medium was supplemented with fructose (1.5%), MnSO4 (1.0 μg/ml), riboflavin (0.10 μg/ml) and Triton X‐100 (0.01%). The possible role of the rhizobial production of IAA on the rhizobia‐legume symbiosis is discussed.
Perspectives of phototrophic microorganisms in environment protection and ecology
Authors: Pulz O. , Kretschmer P.
Published: December 2004

The ecophysiological properties – light effectuated neosynthesis of biomass from inorganics – make microalgae become interesting organisms of preventive and sanitating environmental protection with regard to the inorganic impact. They are filling an underestimated gap.

Medium‐term solutions of the heavy metal accumulation in the tertiary sewage disposal, the trophy sanitation of surface and ground waters and of algal induced recultivation of waste‐land seem to be attainable.

The investigation of the role of microalgae in world‐wide material cycles will be of long‐term importance to biotechnology and global ecology.
Methods of artificial intellect in controlling biotechnological processes (Part 1)
Authors: Kristapsons M. , Sarkisyants L.
Published: December 2004

Presently, an urgent problem is the application of artificial intellect (AI) methods as a complex way of controlling and optimizing technological processes. The paper presents major principles of a bystage application of AI in biotechnology as knowledge extraction from data obtained by decomposing the sign space to clusters.
Purification and enzymatic properties of α‐galactosidase from Penicillium janthinellum
Authors: Elshafei A. M. , Foda M. S. , Aboul‐Enein A. , Afify A. S. , Ali N. H.
Published: December 2004

α‐Galactosidase (E.C.3.2.1.22) from Penicillium janthinellum was purified by precipitation and fractionation with ammonium sulphate, cold acetone or ethanol, calcium phosphate gel, and column chromatographies on Sephadex G‐100 and G‐200. The enzyme was purified about 110.39‐fold when Sephadex G‐100 was used. α‐Galactosidase exhibited the optimum pH and temperature at 4.5 and 60°C, respectively. The optimum enzyme stability was obtained at pH 3.5 for 24 h (at room temperature). The enzyme was found to be thermostable below 65°C up to 40 minutes and was gradually inactivated by increasing the temperature above this degree. The MICHAELIS constant was 0.55 mM for p‐nitrophenyl‐α‐D‐galactoside. The α‐galactosidase activity was strongly inhibited by Hg++ and slightly activated by Mn++. The results show the possibility of producing a thermostable enzyme from a low‐priced agricultural product, for instance, lupine.
Production of propionic acid by microbiological way. Part 2. Effect of the pH value on cell growth and acid production
Authors: Obaya M. C. , Ramos J. , Villa P. , Valdés E. , Eng F.
Published: December 2004

The batch propionic acid fermentation of sugar cane molasses by Propionibacterium acidi propionici PP‐1 was studied at various pH values ranging from 5 to 7. The optimum pH range for cell growth was between 6 and 7, whereas the specific growth rate decreased with the pH in the acidic range down to 0.197 h−1 at pH 5.

The propionic acid yield increased with decreasing pH; it changed from 22% (wt/wt) at pH 7 to 38% at pH 5. It has been obvious that this process is inhibited by the products of the fermentation and more severely in the acidic range where the acids are in an unionized state.

A generalized equation of the non‐competetive inhibition was adjusted for each pH value, and kinetic inhibition constants were estimated.
The influence of MAILLARD's reaction in sugar cane molasses on the kinetic fermentation parameters of Candida utilis NRRL Y‐660
Authors: Otero M. A. , Reyes A. , González J. , Peña M. A.
Published: December 2004

Growth inhibition of Candida utilis NRRL Y‐660 took place in molasses stored at 60°C for 120 days. The specific growth rate (μmax) was reduced from 0.42 h−1 to 0.200 h−1 as a result of a lack of affinity from the microorganism to the substrate and the increasing maintenance necessities. The Ks values arose from 1.40 mg/ml to 4.28 mg/ml within the whole experiment. At the same time, the maintenance coefficient (m) increased from 0.250 to 3.80 mg/ml. In a continuous culture the “wash‐out” conditions were reached at dilution rate values (D) close to 0.40 h−1. The process productivity decreased up to 15% from its original value in fresh molasses.
L‐Methionine production by double auxotrophic mutants of a ethionine resistant strain of Brevibacterium heali
Authors: Mondal S. , Das Y. B. , Chatterjee S. P.
Published: December 2004

A number of lysine plus threonine double auxotrophs have been isolated from a ethionine resistant methionine producing strain of Brevibacterium heali previously isolated from soil by mutagenesis with N‐methyl N′‐nitro‐N‐nitrosoguanidine in two steps. This strain excreted L‐methionine in sufficient amounts. For the three potent mutants tested, the medium of ALFOLDI was judged to be the best. Biotin and ammonium nitrate were found to be optimal at 5 μg/l and at a 40 mM level, respectively. With such an optimal dose, the strain BhLT 27 yielded 25.5 g/l methionine in a flask culture containing methionine‐analogue ethionine at a minimal inhibitory concentration.
Production of oxytetracycline by immobilized Streptomyces rimosus cells in calcium alginate gels
Authors: Farid M. A. , El Diwany A. I. , El Enshasy H. A.
Published: December 2004

Streptomyces rimosus Pfizer 18234–2 cells were immobilized in calcium alginate and used for the production of oxytetracycline. The influence of the incubation period, alginate concentration and storage in CaCl2 were investigated. From the results of the repeated batch fermentations of the shake flasks, a good level of antibiotic was maintained for a period of about 28 days using 4% calcium alginate. The cell leakage and cell concentration inside the beads were affected by the alginate concentration and storage in CaCl2 solution.
Stimulation of multiple shoot regeneration from seedling leaves of Hypericum perforatum L. by pluronic F‐68
Authors: Brutovská R. , Cellárová E. , Davey M. R. , Power J. B. , Lowe K. C.
Published: December 2004

The effects of the non‐ionic surfactant, Pluronic F‐68, on the growth of shoots regenerated from seedlings (14 days post‐germination) of Hypericum perforatum L. were studied. The supplementation of agar‐solidified medium with 0.001% (w/v) of Pluronic increased the mean fresh weight of the regenerants after 60 days by 40% and the mean number of plant regenerants recovered per seedling by 34%; a less pronounced increase in the number of regenerants occurred with 0.01% (w/v) of the surfactant. By contrast, the mean fresh weight of the regenerants cultured in the presence of 0.1% (w/v) Pluronic F‐68 was 15% lower than untreated controls, although the mean number of regenerants per seedling remained unaltered. The growth of seedling leaf‐derived Hypericum callus after 60 days was unaffected by all the concentrations of Pluronic tested. However, there was a tendency for callus cells grown in the presence of Pluronic to be more highly pigmented with anthocyanins. The cultivation of leaf explants with 0.001% or 0.01% (w/v) Pluronic did not affect either the mean fresh weight of the regenerants or the mean number of regenerants per explant. However, decreases in both the mean fresh weight and the mean number of regenerants (both 33.0% lower than the control) occurred following the cultivation with 0.1% (w/v) Pluronic.
Glucose oxidase biosynthesis in relation to biochemical mutations in Aspergillus niger
Authors: Fiedurek J. , Szczodrak J.
Published: December 2004

The production of extracellular glucose oxidase in a submerged culture by a number of auxotrophic, 2‐deoxy‐D‐glucose resistant and protease‐less mutants of Aspergillus niger was evaluated. Among the auxotrophic strains, no evident dependence was found between the kind of the nutritional requirements and the level of the glucose oxidase activity. However, the majority of auxotrophs, requiring serine or niacin, showed a higher enzyme activity (from 16 to 680%) than the parent strain. The dynamics of the glucose oxidase synthesis by the free and immobilized mycelium of the most active niacin− mutant of A. niger was also investigated.
Changes in protein secretion of Aspergillus niger caused by the reduction of the water activity by potassium chloride
Authors: Bobowicz‐Lassociska T. , Grajek W.
Published: December 2004

The effect of the rapid reduction of the water activity (aw) on the extracellular protein and amylolytic activity of Aspergillus niger was studied. An aw value gradient from 0.90 to 0.99 in KCl solutions was applied for the mycelium treatment. It was found that the aw reduction considerably influenced the protein secretion. This phenomenon was dependent on the age of the treated mycelium and the range of the aw gradient. The highest protein and enzyme secretion yields were obtained at aw = 0.98 using a 72‐h old mycelium. In comparison with the non‐treated mycelium, the increase in the secretion amounted to about 60% for the amylolytic activity and 37% for the soluble protein, respectively. It was shown that the mycelium incubated in KCl solutions of an aw value from 0.90 to 0.99 had the ability for regeneration in fresh CZAPEK‐DOX medium. The effect of the osmotic shock on the protein secretion was limited only for the treated cell population and declined in the mycelium which was regenerated after the transfer into the culture medium.
Non‐selective precultivation of bacteria able to degrade different polycyclic aromatic hydrocarbons (PAH)
Authors: Mahro B. , Rode K. , Kasche V.
Published: December 2004

The influence of the precultivation with different carbon sources on the ability of three different bacterial strains (Sphingomonas sp. strain BA2, Gordona sp. strain BP9, Mycobacterium sp. strain VF1) to grow on phenanthrene. anthracene, pyrene or fluoranthene as the sole source of carbon and energy were studied. The strains were found to maintain their ability to grow on two of the four PAH after 30 serial transfers in liquid nutrient broth medium without selective pressure. The ability to grow on these PAH as the sole carbon and energy source was also maintained after curing experiments with acridine orange. The high stability of the PAH‐degradation phenotype suggests that the tested strains carry at least parts of the PAH‐degradation pathway genes on the chromosome. The PAH‐degradation versatility of the strains was also influenced by the carbon source being used for precultivation. Possible reasons for the particularly good impact of the precultivation on hexadecane on the PAH degradation are discussed in this paper.
Improved ethanol production from whey with Saccharomyces cerevisiae using permeabilized cells of Kluyveromyces marxianus
Authors: Rosenberg M. , Tomáška M. , Kaňuch J. , Šurdík E.
Published: December 2004

Permeabilized cells of Kluyveromyces marxianus CCY eSY2 were tested as the source of lactase in the ethanol fermentation of concentrated deproteinized whey (65–70 g/l lactose) by Saccharomyces cerevisiae CCY 10–13–14. Rapid lactose hydrolysis by small amounts of permeabilized cells following the fermentation of released glucose and galactose by S. cerevisiae resulted in a twofold enhancement of the overall volumetric productivity (1.03 g/l × h), compared to the fermentation in which the lactose was directly fermented by K. marxianus.
Enhancement of the biological degradation of soils contaminated with oil by the addition of compost
Authors: Hupe K. , Lüth J.‐C. , Heerenklage J. , Stegmann R.
Published: December 2004

The fundamentals of the biological treatment of contaminated soils were investigated in bioreactors with the aim to optimize the processes of biological soil treatment in order to achieve the highest possible degree of degradation within the shortest period of time. Preinvestigations using test systems at different scales have provided information about the possibilities of enhancing the decomposition processes which are dependent on various factors, such as milieu conditions, additives, etc., that must be known before remedial actions are taken.

The investigations made so far have shown that compost is a favourable additive when oil‐contaminated soils are biologically treated. The degradation of contaminants can be enhanced by the addition of compost. This positive effect is attributed to various mechanisms. In this paper, results of a variety of test systems at different scales are presented.

In test series, different amounts of biocompost were added to investigate the influence on the degradation of diesel fuel. It was demonstrated that by increasing the compost content – the cumulative O2 consumption caused by the degradation of the diesel fuel contaminants increased.

It could be shown that the reduction of the diesel fuel contaminants in the soil was independent of the compost age and amounted to approximately 94% of the initial quantity.

The addition of biocompost could also enhance the degradation of real contaminants. After a test period of 162 days in set‐ups with compost addition, more than 75% of the lubricating oil contaminants disappeared, while less than 37% of the contaminants disappeared in set‐ups without compost addition.

Moreover, by the addition of compost, the formation of pellets during the dynamic treatment of soil materials could be reduced.
Performance of industrial scale bioreactors with modified RUSHTON turbine agitators
Authors: Roman R. V. , Tudose Z. R. , Gavrilescu M. , Cojocaru M. , Luca S.
Published: December 2004

The data presented here with respect to the behaviour of industrial scale stirred tank bioreactors equipped with modified RUSHTON turbine agitators in the biosynthesis processes of antibiotics are valid for that case that the power consumption is the same as it is in standard RUSHTON turbine agitators.

Each modified RUSHTON turbine agitator was obtained through the variation of the blade surface by adding perforations so that the ratio between the perforation surface area and the full surface area (or the surface fraction of the perforations) is 0.36.

In the fermentations of Streptomyces aureofaciens, Streptomyces rimosus and Penicillium chrysogenum producing tetracycline, oxytetracyline and penicillin, respectively, in bioreactors equipped with modified RUSHTON turbine agitators, the relative antibiotic production is increased by more than 30% compared to standard bioreactors.
Isolation and characterization of an alkaliphilic bacterium capable of growing on 2,4‐dichlorophenoxyacetic acid and 4‐chloro‐2‐methylphenoxyacetic acid
Authors: Hoffmann D. , Müller R. H. , Kiesel B. , Babel W.
Published: December 2004

A bacterial strain, called P4a, was isolated from debris of concrete samples of a demolished herbicide factory. The samples were contaminated with chlorinated and methylated phenoxyalkanoic acids. Strain P4a was able to utilize 2,4‐dichloro‐ (2,4‐D) and 4‐chloro‐2‐methylphenoxyacetic acid (MCPA) as the sole source of carbon and energy; degradation of 2,4‐dichlorinated and 4‐chloro‐2‐methylated phenoxypropionic acid and ‐butyric acid derivatives was not found. Growth on 2,4‐D was observed from a pH of 5.6 up to a pH of about 10, with optimum growth at around 8.5. No supplements were found to be required for growth on 2,4‐D, but the presence of yeast extract increased the growth rate from less than 0.05 h−1 to 0.2 h−1. The strain was metabolically active up to pH values of 12, which corresponded to the pH of aqueous eluates from such material. It was able to degrade 2,4‐D under these conditions up to an initial concentration of 400 mg/1 and in fact did degrade 1,600 mg/l of 2,4‐D at an initial pH value of 11. Strain P4a was tentatively identified as Comamonas acidovorans on the basis of the substrate utilization pattern (BIOLOG), fatty acid profile (MIS) and G+C content.
Selection of hemicellulosic hydrolysate pretreatments and fermentation conditions to stimulate xylitol production by ethanol‐producing yeasts
Authors: Converti A. , Del Borghi M.
Published: December 2004

Xylitol production from hardwood hemicellulosic hydrolysates by well‐known ethanol‐producing yeasts was stimulated through an experimental schedule including pretreatments of the hydrolysate, the choice of the best xylitol producer and the selection of the optimum fermentation conditions. The xylitol or ethanol yields obtained on consumed xylose demonstrated that their production was stimulated under completely different conditions, as to be expected by the fact that these catabolites are the final products of different metabolic pathways. In particular, the catabolism of Pachysolen tannophilus, that is the best ethanol producer from this natural substrate, could be targeted towards xylitol rather than towards ethanol production by ensuring a strongly reducing environment through a suitable pretreatment of the hydrolysate. The final removal of fermentation inhibitors by adsorption onto highly adsorbing substances allowed a further 20% xylitol yield increase.
Mixing times in an external‐loop airlift bioreactor with static mixers
Authors: Gavrilescu M. , Roman R.‐V.
Published: December 2004

The influence of static mixers on mixing time and circulation time in an external‐loop airlift bioreactor with gas‐induced and forced‐liquid circulation was investigated.

The study was carried out with water and three viscous, non‐Newtonian starch solutions. The mixing time was determined for the overrall flow loop using a classical tracer response technique.

It was found that the mixing time is highly dependent on the superficial gas velocity and the presence of static mixers. The shortest mixing time is achieved in a forced‐loop airlift reactor without static mixers, where the average mixing time value is only 1/3 of the time necessary for mixing in the airlift reactor with gas‐induced liquid circulation and static mixers.

The pseudoplasticity of the liquid phase insignificantly influences the mixing time and the circulation time.
Hydrolyzed whey as a medium for propionic acid fermentation
Authors: Czaczyk K. , Trojanowska K. , Wiszumirska E.
Published: December 2004

Whey, hydrolyzed by using pure enzymes and enzymatic preparations, was fermented by propionic acid bacteria in batch cultures. The course of propionic acid fermentation was examined by the determination of cell dry weight, lactose utilization, production of volatile free acids and biosynthesis of vitamin B12. The production of propionic acid by Propionibacteria increased when hydrolyzed whey was used as a medium. It rose from 6.3 to 6.7 g/l in the control compared to 8.0–8.8 g/l when pepsin, papain, alcalase, or pescalase were applied as hydrolyzing agents. A significant decrease in the biosynthesis of vitamin B12 (more than 50%) was observed in all cases compared to the control (cultivation on medium without hydrolysis).
Flow cytometric discrimination between Acinetobacter calcoaceticus 69‐V and Alcaligenes eutrophus JMP134 by fluorescently labelled rRNA‐targeted oligonucleotide probes and DNA staining
Authors: Herrmann C. , Babel W. Th. , Lösche A. , Müller S. , Bley S.
Published: December 2004

In situ hybridization with fluorescently monolabelled rRNA‐targeted oligonucleotide probes (17 to 18 nucleotides) was used to discriminate between Alcaligenes eutrophus JMP 134 and Acinetobacter calcoaceticus 69‐V by flow cytometry. The strains were grown in batch experiments in a mixed population. The forward light scatter and fluorescence of each bacterial cell were measured with a single laser cytometer. The intensity of fluorescence after rRNA staining depended on the content of ribosomes, which correlated with the growth rate of bacteria. Therefore exponentially growing cells could be clearly detected. For other growth phases, signal amplification was necessary using multiple probes. The two bacterial strains were identified with differently labelled probes under an epifluorescent microscope. Using a single laser cytometer, rRNA based identification was possible nut not ideal. Better discrimination between the two strains of the mixed population was achieved by DNA staining, combined with the different forward light scatter signals. Due to the significantly different cellular DNA and GC content of both strains, the fluorescent dye DAPI (4′, 6‐diamidino‐2‐phenylindole), preferring AT‐rich regions of DNA, was found to be a supplementary tool for population analysis. The abundance ratios of the two strains in mixed culture determined by DNA or rRNA staining were similar.
Studies on cultivation, biological efficiency and chemical analysis of Pleurotus sajor‐caju (FR.) SINGER on different bio‐wastes
Authors: Patrabansh S. , Madan M.
Published: December 2004

Three different kinds of biomass, namely Populus deltoides, Eupatorium adenophorum and sericulture waste were used individually for the cultivation of Pleurotus sajor‐caju, alone and mixed with paddy straw. P. sajor‐caju, when used alone, exhibited a very good colonizing ability on these substrates, except in sericulture waste. The biological efficiency of P. deltoides and E. adenophorum when used as pure substrate was 75 and 77%, respectively, but it increased to 102% when P. sajor‐caju was cultivated in a mixture with paddy straw in a ratio of 1:2. Experiments examining the growth on sericulture waste in both pure and mixed substrate are encouraging. From the analysis of substrate before and after the cultivation of P. sajor‐caju it was noted that subsstrates were enriched in their protein content as a result of growth of this mushroom. The percentage of degradation of cellulose, hemicellulose and lignin showed that P. sajor‐caju is capable of utilizing all three major components. The fruit bodies of P. sajor‐caju were analyzed for crude protein content, crude fat and carbohydrate content. The energy values in the fruit bodies of P. sajor‐caju and different organic wastes were found to vary from 282 to 309 kcal/100 g and from 319 to 467 kcal/100 g, respectively. It was found, however, that the energy recovery from organic wastes by fruit bodies was very low, i.e. 4.19‐8.73 kcal/100g of dry substrate.
Hydrolysis and transformation of cellulose with Aspergillus niger IBT‐90 enzymes
Authors: Galas E. , Pyc R. , Romanowska I.
Published: December 2004

Hydrolysis and transformation of Fibrenier cellulose (USA) with enzymes from Aspergillus niger IBT‐90 was studied. The process was performed at 50°C and pH 4.8 for 24 h using an enzyme complex either as a properly diluted culture filtrate or as a mixture of isolated and purified enzymes from A.niger IBT‐90. In the latter experiments, enzyme‐substrate ratios expressed as units of activity per 1 g of cellulose were as follows: endoglucanase E1 and E2, 40; β‐glucosidase, 40 and cellobio‐hydrolase, 2. Cellulose concentration was 5%. It was proved that the crude celluloytic complex from A. niger IBT‐90 exhibits higher efficiency in the decomposition of cellulose in comparison to the mixture of enzymes isolated from this complex, as was revealed in assays of reducing sugars and determinations of light transmission throughout cellulose fibres using a computer analysis of the microscopic image. Comparison of both the endoglucanases E1 and E2 showed that the first enzyme is more active against cellulose. It liberated more reducing sugars and caused more significant decomposition of fibres. The predominant effect of the endoglucanase E2 was a smoothing of the fibre surface. The cellobiohydrolase split a cellulose fibre into many short fibres.
β‐Galactosidase in immobilized cells of Daucus carota L.
Authors: Poór J.
Published: December 2004

The cell suspension culture Daucus carota L. was permeabilized by Tween 80 and immobilized by glutaraldehyde. β‐Galactosidase showed an optimum pH of 4.7 and an optimum temperature of 55 °C. The enzyme hydrolysis was linear for 3 h, reaching a 65% conversion. A very good level of storage stability was achieved when using dry catalyst, or a solution of 0.15 M NaCl with the addition of chloramphenicol, (l‐methyldodecyl)‐dimethylamin‐4‐oxide (ATDNO), chlortetracycline hydrochloride (CLCTC) or by freezing the immobilized cells in 0.15 M NaCl. The cells characterized by high enzyme activity and stability in long‐term storage showed convenient physicomechanical properties.
Development of toxicity tolerant water hyacinth (Eichhornea crassipes) for effective treatment of raw sewage
Authors: Ayade B. B.
Published: December 2004

Pioneering research efforts in the handling of municipal sewage in developing countries have involved the use of water hyacinth (Eichhornea crassipes) to purify sewage for possible re‐use of the effluent water for domestic purposes. The ability of water hyacinth to remove pollution from raw sewage has been found to be impaired by sewage toxicity. Trials were therefore carried out to adapt water hyacinth to toxicity and thereby increase its ability to remove pollutants from raw sewage. The plants were adapted using an active bio‐degrader consisting of Pseudomonas aeruginosa, Escherichia coli, Klebsiella ozaenae, Klebsiella edwardsiella and Baccillus subtilis. The adaptation progressed through 20, 40, 60 and 80% sewage dilution until plants capable of growth in 100% raw sewage were obtained. Plants were observed for morphological growth and at four weeks, samples were collected for tissue analysis.

The plants progressively absorbed nutrients from sewage up to the fourth week, when signs of toxicity were obsereved through wilting, loss of turgidity and reduction in leaf number. However, plants that survived through a series of adaptations under various sewage dilutions exhibited luxuriant growth on raw sewage. In synergy with the active bio‐degrader, the efficiency of the adapted water hyacinth to remove pollutants (nutrients) from raw sewage was enhanced by 93%.
Characteristics of immobilized thermostable amylases from two Bacillus licheniformis strains
Authors: Ivanova V. , Dobreva E. , Legoy M. D.
Published: December 2004

Covalent immobilization of thermostable α‐amylases from catabolite resistant and sensitive Bacillus licheniformis strains on controlled pore glass (CPG) and porous silica (Spherosil) beads and ionic binding on DEAE‐cellulose, Amberlite and Dowex were investigated. Preparations with satisfactory operational stabilities and activities up to 1,600 U/g of support (ionic binding) and 800 U/g carrier (covalent coupling) were obtained. Immobilization led to a narrowing of the pH interval of maximum activity. The fixed amylases were stable in limited pH regions around the optimum pH level. An enhancement of the enzyme thermostability was observed. Apparent shifts of the optimum temperatures were not found. The apparent Vmax decreased up to 80 times. The Km′ remained unchanged (for amylopectin as the substrate) or increased up to 10 times (soluble starch). Maltose, maltotriose and maltopentaose were the main products of the hydrolysis. A significant increase in maltopentaose content was observed.
Growth of Thermus aquaticus and its TaqI endonuclease production
Authors: Altintas M. M. , Ülgen K. Ö.
Published: December 2004

The culture behaviour of Thermus aquaticus was characterized. The response of the bacterium to various carbon (tryptone, glucose, glycerol) and nitrogen sources (yeast extract, NaNO3, (NH4)2SO4, leucine, thymine, thiamine, glutamic acid) was studied. Amino acids did not support growth, but CASTENHOLZ salt medium supplemented with yeast extract and glucose or tryptone resulted in good growth and production. A suitable medium composition giving the highest biomass concentration and enzyme yield was developed. The simple medium containing TYE‐NaCl resulted in the highest biomass concentration, whereas CASTENHOLZ mineral medium supplemented with tryptone and yeast extract gave the highest specific activity and enzyme yield. The effect of inoculum age and size on growth was also investigated in order to improve the yield and process consistency. The use of shake flasks inoculated with precultures at their early or late stationary phase resulted in the same biomass concentration (0.56 ± 0.015 g/l) and similar maximum specific growth rates (0.258 ± 0.003 h−1). Inoculum sizes between 1 and 2.5 per cent were optimal for cell growth. As the other papers on thermophilic microorganisms, including the T. aquaticus YT‐1 strain, gave qualitative information on growth, the results presented here cannot be compared with others on a quantitative basis. TaqI endonuclease was purified using a 5 step protocol including cell disruption, adsorption, precipitation, column chromatography and final dialysis. The enriched fraction had a specific activity of 33,600 U TaqI endonuclease per mg protein.
Production of extracellular polysaccharides by a Rhizobium species from root nodules of Cajanus cajan
Authors: Datta C. , Basu P. S.
Published: December 2004

The ability of the Rhizobium sp., isolated from the root nodules of the leguminous pulse yielding shrub Cajanus cajan, to produce extracellular polysaccharides (EPS) was checked. A large amount of EPS (1, 128 μg/ml) was produced by the bacteria in yeast extract mannitol medium. Growth and EPS production started simultaneously, but the production reached its maximum level in the stationary phase of growth at 28 h. The EPS production by this Rhizobium sp. was much higher than by many other strains from nodules of Cajanus cajan which took a much longer time to reach maximum EPS production than this strain. The maximum EPS production (2,561 μg/ml) was obtained when the medium was supplemented with mannitol (1%), cetyl pyridinium chloride (2 μg/ml) and KNO3 (0.2%), in which the production was increased by 276% compared to the control. The EPS production rose in the period up to 65 h with increased mannitol concentration. The EPS contained arabinose, xylose and rhamnose monomers. The possible role of rhizobial EPS production in root nodule symbiosis is discussed.
Removal of cadmium by Pleurotus sajor‐caju basidiomycetes
Authors: Cihangir N. , Saglam N.
Published: December 2004

The bioaccumulation of cadmium by the white rot fungus Pleurotus sajor‐caju onto dry biomass was investigated using aqueous media with concentrations in the range of 0.125 mM–1.0 mM The highest cadmium uptake (between 88.9 and 91.8%) was observed with aerobic fungal biomass from the exponential growth phase. Up to 1.0 mM cadmium gradually inhibited mycelium development, but never blocked it completely. Freeze‐dried, oven‐dried and non‐metabolizing live Pleurotus sajor‐caju biomass types were tested for their capacity to adsorb the test ion Cd2+ within the pH range of 4.5 to 6.0. Freeze–dried biomass proved to be the most efficient biomass type for Cd2+ metal adsorption. Therefore, Pleurotus sajor‐caju may be used for heavy metal removal and bioremediation.
Continuous biodegradation of phenoxyalkanoate herbicides by Sphingomonas herbicidovorans MH in a PU‐supplied bubble reactor
Authors: Hinteregger C. , Streichsbier F.
Published: December 2004

The continuous aerobic degradation of phenoxyalkanoate herbicides by Sphingomonas herbicidovorans MH was investigated in a bubble reactor filled with modified polyurethane‐foam (PU 90/51) as a carrier for the adsorptive immobilization of the bacterial cells. The PU‐foam was applied in the form of plates (5 × 10 × 10 mm) and the amount added was equivalent to a PU‐load of 1.25% [w/v]. Strain MH is capable of detoxifying the dichloro‐substituted phenoxyalkanoates 2,4‐DP, 2,4‐D and 2,4‐DB and the methylchloro‐substituted phenoxyalkanoates MCPA, MCPP and MCPB. Degradation of the respective substrate was followed by HPLC analyses and by determination of the chloride release. No intermediates of the degradation pathways or “dead end” products were detected by HPLC analyses. The PU‐bubble reactor with immobilized 2,4‐DP‐pre‐grown cells was run continuously at 30°C at the high dilution rate of D = 0.5h−1 with 2,4‐DP (0.2 g/l), and with subsequent changes to each of the other phenoxyalkanoates as a single substrate in the feed and with an intermittent return to 2,4‐DP. Finally, after an intermediate substrate accumulation, 2,4‐D, 2,4‐DP, MCPA and MCPP could be degraded under the aforementioned conditions corresponding to a maximum degradation rate of Qphen = 100 mg/l × h. In the case of 2,4‐DB, a slightly reduced conversion rate of about 94% could be calculated. In contrast to these results, 0.2 g/l of the more recalcitrant MCPB could not be metabolized at this high dilution rate of D = 0.5 h−1 by the biofilm of Sphingomonas herbicidovorans MH, but it was degradable at a reduced dilution rate of D = 0.25 h−1. Complete detoxification of a stoichiometric mixture of the dichloro‐ and the methylchloro‐substituted phenoxyalkanoates including MCPB, respectively, at a total concentration of 0.2 g/l was achieved at D = 0.25 h−1, corresponding to a degradation rate of Qtot = 50 mg/l × h. Finally, the efficiency of the PU‐immobilized cells of Sphingomonas herbicidovorans MH in detoxifying mixtures of all six herbicides could be increased to Qtot = 75 mg/l × h by the further addition of PU‐foam particles corresponding to a final PU‐load of 2.5% [w/v]. This PU‐bubble reactor was successfully operated for more than 12 months to clean up synthetically concocted waste waters with fluctuations in phenoxyalkanoate concentration and composition.