bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hemicellulolytic enzymes of the ligninolytic white‐rot fungus Phlebia radiata. Influence of phenolic compounds on the synthesis of hemicellulolytic enzymes
Authors: Rogalski J. , Hatakka A. , Longa B. , Wojtaś‐Wasilewska M. 
Published: December 2004

AbstractThe ligninolytic fungus Phlebia radiata growing in a low‐nitrogen medium with wheat bran as the sole carbon source was induced by some lignin monomers, e.g. vanillic, veratric and ferulic acids. In the medium these substances showed a mainly stimulating influence on the hemicellulolytic enzymes activity except for arabinofuranosidase and ferulic acid esterase.
Investigation of the bacitracin biosynthesis in an airlift bioreactor
Authors: Gavrilescu M. , Roman R.‐V. 
Published: December 2004

AbstractResults of pilot plant studies using an external‐loop airlift bioreactor (170 l fermentation volume, liquid height‐to‐riser diameter: 27, loop‐to‐tower cross‐section‐area: 0.1225) have proven the relative merits of such a system in the bacitracin biosynthesis produced by the Bacillus licheniformis submerged aerobic cultivation.The results were compared to those obtained in a pilot‐scale stirred‐tank bioreactor with the same values of kLa. Excepting the aeration rate of 0.2 vvm, the fermentation process performed at 0.5 vvm and 1/0 vvm, respectively, unfolded similarly in the two fermentation devices with respect to the cell mass production, substrate utilization and bacitracin production during the fermentation process.In the riser section of the airlift bioreactor, the dissolved oxygen levels were higher, while in the downcomer section they were lower than those realized in the stirred tank bioreactor.Power requirements of the airlift fermenter were by 17–64% lower than those for a mechanically agitated system, depending on the aeration rates, which led to an important energy saving.Moreover, the lack of mechanical devices in the airlift system provides safety and a more gentle environment for the cultivation of microorganisms.
Staining procedures for flow cytometric monitoring of bacterial populations
Authors: Müller S. , Lösche A. , Bley T. 
Published: December 2004

AbstractDual or multiple parameter flow cytometric analysis is developing into a powerful method for characterizing microbial populations. The distinguishing of the populations only by assignment of size/shape measurements by scattered ligth renders as not satisfactory.To differentiate between the cells, the employment of a specific fluorescence marker is absolutely necessary. Methods are presented for the flow cytometric determination of DNA and the polymer poly‐β‐hydroxybutyrate (PHB) content in three different bacterial strains. The measurement of the 3β‐hydroxysterol content enables the differentation between yeast and bacterial organisms in mixed microbial populations. Monitoring the ratio of live to dead bacterial cells in soil or water samples, e.g. in pure culture systems, is shown.
Investigations into the growth behaviour of a toluene‐degrading Pseudomonas strain, taking the high vapour pressure of toluene into consideration
Authors: Löser C. , Ray P. 
Published: December 2004

AbstractA toluene‐degrading Pseudomonas species isolated from waste water was studied with regard to its growth behaviour. The dependence of the growth rate on the pH value, on the toluene concentration and on temperature, as well as the O2 consumption of the isolate were determined. The fact that toluene is a highly volatile substrate, which is present both in the liquid and in the has phase of a reactor, was considered in the experiments. It is shown that the volatility of toluene has to be taken into consideration for an accurate determination of the toluene concentration in the medium.
Enhancement of methionine production by methionine analogue ethionine resistant mutants of Brevibacterium heali
Authors: Mondal S. , Chatterjee S. P. 
Published: December 2004

AbstractIn order to improve the methionine yield of the isolate B. heali, attempts were made to isolate mutants resistant to the methionine analogue DL‐ethionine after mutagenesis with N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (NTG). The minimum inhibitory concentration (MIC) of ethionine for B. heali was found to be 2 mM. After mutagenesis and screening, five mutants resistant to 50 mM of ethionine were isolated. The yield of the best ethionine resistant mutant, B. heali Br EthR, was 13 mg/l of methionine medium under optimum cultivation conditions.
Heavy metal sorption by marine algae and algal by‐products
Authors: Sandau E. , Sandau P. , Pulz O. , Zimmermann M. 
Published: December 2004

AbstractAll the oceans are plentiful with marine algae. Non‐viable marine macroalgae are able to adsorb heavy metal ions. Compared with other biosorbents, such as fungi, bacteria, yeasts and microalgae, they have the advantage of being easily available, cheap and having high heavy metal sorption capacities. The by‐products of marine phaeophyceae are even more cost‐effective heavy metal biosorbers.Experiments of heavy metal sorption using non‐viable Fucus vesiculosus, Ascophyllum nodosum and algal by‐products were carried out to investigate the factors influencing and optimizing the heavy metal biosorption.The pH value, biomass concentration, heavy metal concentration, heavy metal species, competing ions, algal varieties and time were the most decisive parameters. The sorption isotherms showed increasing sorption capacities and decreasing sorption efficiencies with an increase in the initial heavy metal concentration. Sorption kinetics of different metals were established. Biomass concentration influenced the sorption efficiencies very much, but reduced the sorption capacity per g biomass. The pH value controlled the sorption (pH 3–7) and desorption (pH 1–2) decisively.Beside heavy metal contaminated model waters, actual industrial effluents were treated successfully by algal sorbents in batch experiments and continuous column tests.Transmission electron micrographs of different contaminated and untreated algal specimens are available.
Investigations into the antibiotic activity of tea fungus/kombucha beverage
Authors: Steinkraus K. H. , Shapiro K. B. , Hotchkiss J. H. , Mortlock R. P. 
Published: December 2004

AbstractTea fungus/kombucha, an acetic acid flavoured fermented tea beverage, is widely consumed in various parts of the world and has more recently become a fad in the United States. This is due in part to the fact that it can be produced in the home, and it is reported to be medicinal, effective against arthritis, psoriasis, chronic fatigue, constipation, indigestion and metabolic diseases. Among 264 references from 1852 to 1961, there are reports of antibiotic activity against Agrobacterium tumefaciens and medicinal value against a variety of diseases. The medicinal value appears to be related to that attributed to vinegar, one of our most ancient foods. We decided to test tea fungus/kombucha for its antibiotic activity against Helicobacter pylori, a primary cause of gastritis related to peptic ulcers and gastric carcinoma, Escherichia coli, Staphylococcus (Micrococcus) aureus and Agrobacterium tumefaciens. Tea containing 4.36 g of dry tea per litre and 10% of sucrose and fermented with the tea fungus showed no antibiotic activity in the beverage beyond that caused by acetic acid, a primary product of the fermentation.
Application of an airlift bioreactor to the nystatin biosynthesis
Authors: Gavrilescu M. , Roman R.‐V. 
Published: December 2004

AbstractPilot plant studies were performed using a concentric‐tube airlift bioreactor of 2.5 m3 fermentation volume. The results have proven the relative merits of such a system in the biosynthesis of nystatin, produced by Streptomyces noursei, in submerged aerobic cultivation and batch operation mode. The results were compared to those obtained in a pilot‐scale stirred tank bioreactor of 3.5 m3 fermentation volume.The fermentation processes in the two fermentation devices were similar with respect to substrate utilization, biomass production and nystatin biosynthesis.In the riser section, the dissolved oxygen concentration was higher than that in the downcomer.The volumetric oxygen mass transfer coefficient was dependent on the rheological behaviour of the biosynthesis liquids, which was not constant during the fermentation process.The total energy consumption for nystatin production in the airlift bioreactor was 56% of that in the stirred tank, while the operating costs represented 78% of those in the stirred tank bioreactor.
Ethanol fermentation of HTST extruded rye grain by bacteria and yeasts
Authors: Czarnecki Z. , Nowak J. 
Published: December 2004

AbstractHigh temperature extrusion cooking of rye was used as a pretreatment for ethanol fermentation, and yeasts and bacteria were compared for their fermentation rates. Extrusion cooking caused, on average, a 7.5% increase in ethanol yield in comparison to autoclaved samples. The best results were achieved for grain with a moisture of 21‐23% which was extruded at temperatures of 160‐180 °C.Extrusion decreased the relative viscosity of rye grain water extracts, so it was possible to mash it without α‐amylase. The efficiency of fermentation of extruded rye without Termamyl was equal to that of autoclaved and traditionally mashed rye (using α‐amylase).The rate of fermentation of extruded rye grain by Zymomonas was higher during the first stage, but the final ethanol yield was similar for the bacterium and the yeast.Though both microorganisms gave good quality distillates, the concentration of compounds other than ethanol achieved from extruded rye mashes, which were fermented by Z. mobilis, was five times lower than for yeasts.
An advanced method based on artificial intelligence for controlling biotechnological processes (part II)
Authors: Sarkisjants L. , Krishtapsons M. 
Published: December 2004

AbstractA new finite‐state method is proposed which has been designed for use in biotechnological processes, in particular for the control of the pH in acidic waste water.The automation of expedient behaviour takes into account the non‐linear character of the process and a good control stability in spite of variations in the influent acidic concentration, dissociation constant of the acid and change of the pH set point.To design the controller with the proposed method, no model of the process is required. Simulation studies show that expedient behaviour of an automaton in a random medium for the control of the pH neutralization process can give a good performance.
Transformed root cultures for biotechnology
Authors: Wysokinska H. , Chmiel A. 
Published: December 2004

AbstractThis review is concerned with the application of hairy roots, i.e. plant roots formed from plant cells after transformation by Agrobacterium rhizogenes for the production of bioactive compounds. Transformed root cultures have been established from numerous species of dicotyledonous plants. The plants, as well as the main products accumulated in hairy root cultures derived from these plants, are listed in this paper. Data are presented on novel compounds, hitherto detected only in transformed roots but not occurring in the corresponding intact plants.The possible use of hairy root cultures for the over‐production of secondary metabolites and biotransformation of chemicals is discussed. In order to enhance the productivity of hairy root cultures, various methods have been derived, and optimized procedures are proposed. They include selection of high‐producing clones, elicitation, composition of growth media, culture conditions and genetic approach. Hairy roots usually store secondary metabolites in vacuoles inside the cells. Therefore, several methods have been used to increase the amount of products released into the medium. Unfortunately, no general procedure is known that works in all cases, and the excretion behaviour of hairy root cultures varies from one species to another and even within one species from one clone to another.Special attention is given to the cultivation methods and bioreactor systems for hairy root cultures. Hairy roots are cultivated usually in shake flasks; however, shake flask culture is not suitable for the complex optimization and continuous control of the culture conditions. In this paper, we are going to present bioreactors proposed for the cultivation of hairy roots under more or less controlled conditions. Modifications of typical bacterial bioreactors, i.e. stirred tanks, airlift loop reactors and other constructions, are presented. A very special type of bioreactor providing good conditions for loose root mass multiplication without oxygen or substrate limitations, is the mist bioreactor. Nowadays, it is practically impossible to select the one best bioreactor type for hairy root culture.
Estimation of biological kinetic parameters from an analysis of the BOD curve of waste waters–effects of a chemical preoxidation
Authors: Beltrán F. J. , Garcíaaraya J. F. , Álvarez P. 
Published: December 2004

AbstractUrban waste waters were treated with pure ozone or combinations of ozone, hydrogen peroxide and/or UV radiation to study the course of resulting BOD (biological oxygen demand)‐time profiles and to propose a kinetic model. BOD‐time profiles of chemically treated waste waters show an initial lag period that first order kinetic models cannot describe. A second order kinetic model is then proposed that satisfactorily fits experimental BOD‐time profiles, except when hydrogen peroxide has been used. In these cases, BOD‐time profiles present the highest lag periods observed. By applying this model, three parameters are determined: the biokinetic constant (k) which is an index of the biological removal rate; the potential amount of biodegradable matter (BODT), and the measure of the size of inocula and microbial activities of microoganisms (λ). The model was checked with experimental results of BOD‐time profiles corresponding to both untreated and chemically ozonated urban waste waters. Ozonated waste waters showed the highest values of k and BODT, which implies an improvement of waste water biodegradability after ozonation. However, values of λ corresponding to ozonated waste waters presented lower values than those of untreated waste waters. This was due to the lag period observed in the BOD‐time profile, which was a consequence of a lack of microorganism acclimation to ozonated waste waters. The effect of the ozone does, pH and carbonates during ozonation on COD (chemical oxygen demand) and the above indicated parameters was also studied. There was an optimum ozone dose which was 138 mg/l for this specific system. This led to the highest biodegradable fraction (φ) and the highest biokinetic constant (39% increase in φ and 4.7‐ fold increase in the value of k, respectively, compared to untreated waste waters.). Another significant fact was that a higher COD reduction was observed in the absence of carbonate during ozonation at basic pH values. In addition, the percentage of variation in the biodegradable fraction (Δφ) of ozonated waste water increased compared to the untreated waste water at acid pH. The results suggest that ozonolysis, the direct molecular ozone way of reaction, due to its selective character, increases the biodegradability of waste water more than other chemically advanced oxidation processes based on hydroxyl radical reactions.
Isolation of phenoxy herbicide‐degrading Rhodoferax species from contaminated building material
Authors: Ehrig A. , Müller R. H. , Babel W. 
Published: December 2004

AbstractBacterial strains have been isolated from contaminated concrete debris which exhibit the metabolic capability to degrade 2,4‐chlorinated and 4‐chloro‐2‐methyl‐substituted phenols and phenoxyalkanoic acids including phenoxyacetate and phenoxypropionate derivatives. These strains were taxonomically identified. Two of them were found to belong to the β‐subgroup of the proteobacteria and showed strong similarity to Rhodoferax fermentans. Preliminary investigations by PCR amplification using respective primers revealed that the strains harbour tfdA‐like gene sequences.
A comparison of methods for DNA extraction from paraffin‐embedded tissue for microsatellite instability analysis by polymerase chain reaction
Authors: Kullmann F. , Schölmerich J. , Bocker T. , Rüschoff J. 
Published: December 2004

AbstractIn a prospective study, nuclear DNA was extracted from colorectal tumours and normal mucosa which had been fixed in buffered formalin and embedded into paraffin. DNA‐extraction was performed using three different methods: a commercial kit which was not especially created for this use; a known fast procedure without DNA‐cleaning steps; and a more conventional DNA‐preparation protocol with DNA‐cleaning. Using the polymerase chain reaction (PCR), DNA was amplified by being targeted onto two β‐globin fragments with different lengths (536 bp and 989 bp) and (CA)n repeats localized on chromosome 5q (D5S346) and chromosome 17p (TP53CA) with a length of about 100 bp for detection of microsatellite instability. The success rate of microsatellite amplification was 100% with all methods. The 536 bp β‐globin fragment could be amplified with a success rate ranging from 40% to 100%. The amplification of the 989 bp β‐globin fragment was unsuccessful. Significant differences were observed between the three methods in the final DNA concentration and DNA yield. In microsatellite instability studies of paraffin‐embedded tissues, the investigator can expect a high success rate of nearly 100% using any of the described methods.
Immobilization of glucoamylase on polyamide nets
Authors: Miller E. 
Published: December 2004

AbstractThe formation of reactive groups on polyamide nets (nylon 6) and the subsequent immobilization of glucoamylase were investigated. Different mesh sizes of the nets and two chemical methods of enzyme coupling ‐ i( partial hydrolysis of the polyamide with subsequent glutaraldehyde binding and ii) O‐alkylation of the carrier using a treatment with a benzene‐methyl sulphate mixture – were used. The reactivity of immobilized glucoamylase (GA) was tested by hydrolysis reactions using 1% starch solutions. The highest reactivity (140 μg glc/)min × cm2 was obtained for methylated nylon samples attached to a glass rod and by coupling glucoamylase on the nylon surface which had been treated with lysine and glutaraldehyde. This method resulted in a more reactive and more stable preparation of immobilized glucoamylase as compared to a simpler method of coupling glutaraldehyde to partially hydrolyzed nylon.
Ethanol production from native cassava starch by a mixed culture of Endomycopsis fibuligera and Zymomonas mobilis
Authors: González C. , Delgado O. , Baigorí M. , Abate C. , Callieri D. A. , De Figueroa L. I. C. 
Published: December 2004

AbstractThe conversion of starch from unhydrolyzed cassava flour to ethanol by a pure culture of Endomycopsis fibuligera and by a co‐culture of this amylolytic yeast and the bacterium Zymomonas mobilis was studied.The best overall results were obtained using the mixed culture. After 96 h of fermentation of a medium containing 150 g/l initial cassava starch, an ethanol concentration of 31.4 g/l, a productivity of 0.33 g ethanol/l × h and a yield of 0.21 g ethanol/g initial starch were reached. The highest yield (0.37 g/g) was obtained after 48 h when using a medium containing 50 g/l initial starch.
Hydrolysis of cellobiose using β‐glucosidase from Penicillium funiculosum. Kinetic analysis
Authors: Romero M. D. , Aguado J. , Rodriguez L. , Calles J. A. 
Published: December 2004

AbstractThe kinetics of cellobiose hydrolysis was studied using β‐glucosidase from Penicillium funiculosum, both free and immobilized on nylon powder, at different temperatures, pH values, enzymatic activities and initial cellobiose and glucose concentrations.The experimental results were fitted to a kinetic model by considering the substrate and product inhibitions as well as the thermal deactivation of β‐glucosidase with a mean deviation of less than 10%. The immobilization of β‐glucosidase led to an increase in the stability of the enzyme against changes in the pH value.
Ethanol utilization for metabolite production by Candida utilis strains in liquid medium
Authors: Domenech F. , Christen P. , Páca J. , Revah S. 
Published: December 2004

AbstractEthanol has been reported to be a gaseous pollutant, originating from the agricultural industry. Interest in its biodegradation has increased over the last two decades. Most of the current studies have focused on its elimination by mixed cultures. This study is part of a broader project intended to utilize Candida utilis strains for gaseous ethanol elimination and to eventually bioconvert them into biomass and/or volatile metabolites. We present here the study of six strains (one from the ATCC and five from the ICIDCA collection) cultivated in a liquid medium, with initial ethanol concentrations of 16 g/l and 32 g/l. At 16 g/l, a maximum ethanol elimination rate of 0.13 g/l × h was obtained in four of the six strains (ATCC 9950, L/375–1, L/375–5 and L/375–10). This rate increased to 0.21 g/l × h with an initial ethanol concentration of 32 g/l. The L/375–5 strain was the best biomass producer (3.3 g/l) at 32 g/l, while the highest ethyl acetate production (0.80 g/l) was obtained with the L/375–1 strain. The L/375–25 and L/375–26 strains which showed very low ethyl acetate production were, by way of contrast, efficient acetaldehyde producers, with 0.54 g/l and 0.66 g/l measured in the broth. While biomass production reached its maximum after two days of culture, the production of acetic acid and ethyl acetate continued during the third day. The results for biomass and metabolite production obtained with the ICIDCA collection strains (L/375–1, L/375–5 and L/375–10) were better than those obtained with the ATCC 9950 strain, although the latter often has been reported to be particularly suitable for metabolite production.
Use of natural polymers as immobilizing agents and effects on the growth of Dunaliella salina and its glycerol production
Authors: Thakur A. , Kumar H. D. 
Published: December 2004

AbstractAgar‐agar, agarose, carrageenan and calcium alginate were used for the immobilization of Dunaliella salina cells. Out of the four, agar‐agar was found to be the most effective and therefore the study was carried out on it using different pH values ranging from 6 to 10 and cell densities from 0.1 to 0.8 μg chlorophyll (chl, a) per bead to find which are is best suited for glycerol production. The maximum glycerol production of 9.2 μM/mg chl a was recorded in agar‐agar immobilized algae and this was followed by 8.4 μM/mg chl a in calcium alginate. The maximum cell number 6.2 × 109/ml and the specific growth rate (μ) of 0.80 l/day were reached at pH 8 in agar‐agar immobilized algae. It was shown that the maximum amount of glycerol was produced when the cell density was 0.8 μg chl a/ block. Changing the medium after 24 hours affected the rate of glycerol production at different pH values. Using a cell density of 0.8 μg chl a/block at 16 W/m2 light intensity increased the glycerol production in comparison with the use of free living cells.
Methylobacterium rhodesianum produces poly‐3‐hydroxybutyrate and after mutagenesis in addition exopolysaccharides
Authors: Breuer U. , Babel W. 
Published: December 2004

AbstractMethylobacterium rhodesianum MB 126, a pink‐pigmented facultatively methylotrophic bacterium that uses that serine pathway for the assimilation of reduced C1 compounds, is able to produce poly‐3‐hydroxybutyrate (PHB) under certain limitation conditions. Mutants of this bacterium, which were isolated after the treatment with sodium nitrite, are impaired in their ability to synthesize PHB, but produce another polymer in addition to PHB, namely an exopolysaccharide (EPS). This paper attempts to explain this surprising behaviour.