bluuebunny/crossref_metadata_2025_split huggingface dataset:
The microbial conversion of different agricultural residues and its biological efficiency
Authors: Patrabansh S. , Madan M. 
Published: December 2004

AbstractA number of agricultural residues such as Saccharum munja Roxb. (Sarkanda), Oryza sativa L. (Paddy straw, as the control), Vinna unguiculata (L.) Walp (Cowpeas), Abelmoschus esculentum (L.) Moench (Lady's finger), Zea mays L. (Maize) and Cyamopsis tetragonoloba (L.) Taub. (Guar) were used for the cultivation of Pleurotus sajor‐caju (Fr.) Singer. The biological efficiency of the fruit bodies of Pleurotus sajor‐caju from the above mentioned substrates were found to be 13.47, 11.20, 8.37, 8.31, 6.87, and 6.08 percent, respectively. S. munja and paddy straw were found to be the best substrates for the growth of P. sajor‐caju followed by Z. mays, V. unguiculata, A. esculentum, and C. tetragonoloba.
Yeast entrapment in Duckweeds: Immobilization performance and biomass localization within the support particles
Authors: Richter E. , Ehwald R. , Blinkrei K. 
Published: December 2004

AbstractCell structured support material (CSM) prepared from Wolffia arrhiza fronds were loaded with Saccharomyces cereevisiae by the propagation of yeast cells introduced in the aerenchyma. The loading process could be strongly accelerated by preventing the growth of freely suspended yeasts in the fermenter. The pathway of the inoculation through the stomata could be visualized by transparent light microscopy of amylase and protease treated CSM. Slices of the loaded CSM clearly showed that the framework of the inner chlorenchyma cells remains intact during the propagation of the included yeast cells. Most of the yeast cells were found to be localized as a dense suspension within unbroken cells. During long‐term treatment of the loaded CSM at high convection, about one third of the yeasts was released into water with a constant rate greater than 0.34 h−1. The residual amount of yeast cells remained in a stable compartment from which further loss did not occur for the period tested (20–48 h). It is assumed that the stable compartment is identical with the interior of chlorenchyma cells. The results are discussed in relationship to the possible use of the immobilized biomass in fermentation.
Determination of the Ks values during the growth of Alcaligenes eutrophus on phenol, 2,4‐dichlorophenoxyacetic acid and fructose
Authors: Müller R. H. , Babel W. 
Published: December 2004

AbstractThe determination of the KS values presented here is based on the estimation of the stationary substrate concentrations in continuous cultivation experiments. The separation of biomass from the suspension was performed by an ultrafiltration step which succeeded within one second. The decay of substrate concentration during sampling was calculated to amount to less than 6% of the stationary substrate concentration at relevant growth rates. The KS values derived from these reduced substrate concentrations deviated by only 10% from the theoretical values at a biomass concentration of about 1 g/1. Thus relevant kinetic parameters can be calculated from the data obtained by this procedure. Values of 11, 59 and 14 μM were obtained with 2,4‐dichlorophenoxyacetic acid (2,4‐D), phenol and fructose, respectively. Similar KS values were derived with 2,4‐D and fructose by using a respirationbased determination for reasons of comparison. With phenol this value was only 7 μM which is as cribed to a physiological background.
Xylitol formation by Candida guilliermondii grown in a cane bagasse hemicellulosic hydrolysate: Effect of aeration and inoculum adaptation
Authors: Felipe M. G. A. , Vitolo M. , Mancilha I. M. 
Published: December 2004

AbstractThe xylose conversion into by Candida guilliermondii was evaluated in sugar cane bagasse hemicellulosic hydrolysate. The effect of air flow rates of 0.4, 0.6 and 0.8 vvm cn xylitol formation was studied. In addition, inoculum previously adapted to the hydrolysate was also tested in the fermentation carried out at 0.6 vvm. The results showed that xylitol production depends markedly on the aeration rate and on the previous adaptation of the yeast to the hydrolysate. When the highest productivity of xylitol was 0.39 g/l × h. However, during the fermentation carried out at an air flow rate of 0.6 vvm with adapted inoculum, the productivity increased to 0.65 g/l × h. Furthermore, the adapted cells performed quite well in the presencel of acetic concentrations of about 4.5 g/l in the medium.
Production of extracellular polysaccharides by a Rhizobium species from the root nodules of Tephrosia purpurea Pers
Authors: De P. S. , Basu P. S. 
Published: December 2004

AbstractThe Rhizobium sp., isolated from the root nodules of the leguminous climbing herb, Tephrosia Purpurea Pers., produced high amounts of extracellular polysaccharides (EPS) in yeast extract mannitol medium. Growth and EPS production started simultaneously, but the production reached its maximum in the stationary growth phase of the bacteria. Attempts were made to optimize the cultural requirements for growth and maximum EPS production. The EPS production was increased by 72.5% over the control when the medium was supplemented with mannitol (2%), thiamine hydrochloride (5 μg/ml) and KNO3 (0.1%). The EPS contained glucose, galactose and mannose monomers. The possible role of the rhizobial EPS was discussed.
Culture conditions for the production of amylolytic enzymes by a thermophilic Clostridium sp.
Authors: Odibo F. J. C. , Ulbrich‐Hofmann R. 
Published: December 2004

AbstractThe growth of a thermophilic Clostridium sp. and the production of α‐glucosidase, α‐amylase and pullulanase were studied under anaerobic conditions using different carbon and nitrogen sources and varying pH values and temperatures. Growth and enzyme activities were highest with soybean meal as the nitrogen source. The optimum concentration was 2.5% [w/v] for the production of α‐amylase as well as pullulanase and 2% [w/v] for α‐glucosidase. The best carbon source proved to be soluble starch for α‐amylase, and pullulanase and maltose for α‐glucosidase. Growth and enzyme production reached their optimum at pH 6.5 to 7.0 and 70°C. Under these conditions, the enzyme activities followed exponential growth with maximum yields of α‐glucosidase, α‐amylase and pullulanase at 28, 36, and 44 h.
Degradation of waste waters from olive oil mills by Yarrowia lipolytica ATCC 20255 and Pseudomonas putida
Authors: De Felice B. , Pontecorvo G. , Carfagna M. 
Published: December 2004

AbstractWaste waters from olive oil processing may cause severe pollution in the Mediterranean area, since they have a high level of chemical oxygen demand (COD) (100–200 g/l) and contain other organic and inorganic compounds. In all olive oil producing countries, the reduction of pollution in olive oil mill waste waters at reasonable costs and using techniques suitable for most industrial applications is an unsolved problem.For this paper, the yeast Yarrowia lipolytica ATCC 20255 was grown on waste waters from an olive oil mill in a 3.5 1 fermenter under batch culture conditions.The results showed that the yeast was capable of reducing the COD value by 80% in 24 h. In this way, a useful biomass of 22.45 g/l as single cell protein (SCP) and enzyme lipase were produced.During this process, most of the organic and inorganic substances were consumed, only aromatic pollutants were still present in the fermentation effluents. Therefore, we used a phenol degrader, namely Pseudomonas putida, to reduce phenolic compounds in the fermentation effuents after removing Yarrowia lipolytica cells. P. putida was effective in reducing phenols in only 12 h.
The role of formate for the growth of Rhodococcus opacus UFZ B 408 on pyridine
Authors: Brinkmann U. , Babel W. 
Published: December 2004

AbstractR. opacus UFZ B 408 is able to use pyridine, a potentially growth‐inhibiting substrate, as the sole source of carbon, energy and nitrogen. In a previous publication [1] we reported that with the simultaneous utilization of a second carbon and energy source in carbon‐substrate‐limited chemostat culture, stable steady states could be achieved at higher dilution rates than with growth on pyridine as the sole substrate. Owing to the higher growth yield during growth on such a substrate mixture, both the specific pyridine consumption rates and the residual pyridine concentrations were lower at similar dilution rates than with growth on pyridine alone. Therefore, the critical growth‐inhibitory pyridine concentration was only achieved at a higher dilution rate.With the investigations presented here in carbon‐substrate‐limited continuous culture, the simultaneous utilization of pyridine and formate by R. opacus UFZ B 408 was studied. The yield coefficient during growth on pyridine as the sole substrate amounted to about 0.55 g dry mass/g pyridine. Theoretically, however, the carbon‐metabolism‐determined yield coefficient should have been about 0.915 g dry mass/g pyridine. Because of the difference between these two values the conclusion was drawn that pyridine is energetically deficient. That means that during growth on pyridine a part of the substrate was dissimilated to supply the energy required for the incorporation of the pyridine carbon into biomass. Formate cannot be used as a carbon source for growth by R. opacus UFZ B 408. However, with growth on pyridine, formate was oxidized simultaneously. During growth on pyridine/formate mixtures, the yield coefficient could be enhanced up to 0.7 g dry mass/g pyridine. That means that biologically usable energy, generated in the course of the formate oxidation, was used for the assimilation of pyridine carbon. The increase in the yield coefficient was related to the utilization ratio of formate to pyridine in a linear manner. However, the carbon‐metabolism‐determined yield coefficient of 0.915 g dry mass/g pyridine could not be achieved. That can be put down to the fact that R. opacus UFZ B 408 possesses only a limited capacity to oxidize externally supplied formate. Because of the limited formate oxidation capacity the probability is low that, with simultaneous utilization of formate, stable steady states could be achieved at substantially higher dilution rates than with growth on pyridine alone.Enzymatic studies revealed the induction of both NAD(P)+‐linked glutaric dialdehyde dehydrogenase and isocitrate lyase during growth on pyridine. Therefore, the conclusion was drawn that pyridine is metabolized by R. opacus UFZ B 408 via the same pathway described for the utilization of pyridine by Nocardia Z1 [2]. This conclusion implies that the ability to oxidize formate represents a metabolic performance which seems not to be directly related to the pyridine metabolism of R. opacus UFZ B 408.
Modelling L‐glutamic acid production with Corynebacterium glutamicum under biotin limitation
Authors: Bona R. , Moser A. 
Published: December 2004

AbstractThe production of L‐glutamic acid with Corynebacterium glutamicum under biotin limitation was studied. Assuming a formal type of cell maturation, an adequate formal kinetic model was developed. This model includes growth, dependent on biotin, and uses the same retention term for describing the lag phase and cell maturation. Special attention was paid to the graphical interpretation of the performance between the variables, which is relevant for kinetics. Comparison between experiments and the model resulted in different degrees of agreement. However, the main trend of the experimental patterns of the complex bioprocess can clearly be mirrored in this model.
Production of indole acetic acid in root nodules and culture by a Rhizobium species from root nodules of the fodder legume Melilotus alba DESR.
Authors: Datta C. , Basu P. S. 
Published: December 2004

AbstractThe root nodules of Melilotus alba DESR., a fodder legume, contained high amounts of IAA. A tryptophan pool present in the nodule might serve as a source of IAA production. Presence of IAA oxidase and peroxidase in the nodules indicated the metabolism of IAA, at least in part, in the nodules. The Rhizobium species isolated from the root nodules produced a high amount of IAA (190 μg/ml) from L‐tryptophan supplemented basal medium. IAA production and microbial growth were coincident. The production of IAA by the Rhizobium sp. was increased by 315% when the medium was supplemented with lactose (1%), NiCl2 (10 μg/ml), cetyl pyridinium chloride (0.5 μg/ml) and glutamic acid (0.4%), in addition to L‐tryptophan (3 mg/ml). The possible role of the rhizobial production of IAA on the rhizobia‐legume symbiosis is discussed.
Influence of oxygen on the degradation of diesel fuel in soil bioreactors
Authors: Hupe K. , Heerenklage J. , Woyczechowski H. , Bollow S. , Stegmann R. 
Published: December 2004

AbstractIn fixed‐bed bioreactors, the influence of the oxygen content in the inlet air on the biodegradation of diesel fuel in unsaturated soil/compost mixtures was analyzed at 30°C over a period of 7 weeks. Firstly, a wide range from 0 to 80 vol.% O2 was investigated. Subsequently, the range below 5 vol.% O2 was examined more closely. Over the whole test period of seven weeks, no significant influence of oxygen could be observed above 1 vol. % O2 in the inlet air ‐ either on the decrease of the total contaminants or on the total mineralization. Anaerobic conditions should be avoided for the degradation of diesel fuel. During the test period, the courses of CO2 production varied significantly depending on oxygen supply. Furthermore, a model was developed to estimate the total mineralization as a function of oxygen supply. More investigations are recommended in order to test this model for practical application.
Detection of chlorocatechol 1,2‐dioxygenase genes in proteobacteria by PCR and gene probes
Authors: Kleinsteuber S. , Hoffmann D. , Müller R. H. , Babel W. 
Published: December 2004

AbstractIn various bacterial strains belonging to the β‐subdivision of proteobacteria which are capable of degrading chlorinated monoaromatic compounds, chlorocatechol 1,2‐dioxygenase genes were detected by PCR and Southern hybridization. Using PCR primers derived from the conserved sequence motifs of chlorocatechol 1,2‐dioxygenase genes tfdC, clcA and tcbC, PCR products of the expected size were obtained with the test strains, but not with negative control strains. The specificity of the PCR products was verified by hybridization using an oligonucleotide probe for an internal sequence motif which is evolutionarily conserved among chlorocatechol 1,2‐dioxygenases and some other dioxygenases that catalyze the intradiol aromatic‐ring‐cleavage. Hybridization with the tfdC PCR product from the 2,4‐D degradative plasmid pJP4 under stringent conditions revealed different extents of homology of the chlorocatechol 1,2‐dioxygenase genes to the canonical tfdC sequence in the various strains. These findings were confirmed by the nucleotide sequence analysis of the tfdC‐specific PCR products. From our results, we conclude that the PCR primer set is more suitable than the hybridization with pJP4‐derived gene probes for the detection of diverse chlorocatechol 1,2‐dioxygenase genes in proteobacteria.
Microbial cleaning of waste gas containing volatile organic compounds in a bioreactor system with a closed gas circuit
Authors: Berthe‐Corti L. , Conradi B. , Hulsch R. , Sinn B. , Wiesehan K. 
Published: December 2004

AbstractThe cleaning of the exhaust gases of a bioreactor containing volatile hydrocarbons in a bioreactor system with a closed gas circuit is described. The bioreactor system consisted of three different reactor types: a stirred tank which was filled with hydrocarbon‐containing waste water to simulate the exhaust gases of a remediation process; a trickle‐bed reactor for aerobic treatment of the exhaust gas from the stirred tank; and a photoreactor containing an algae culture which assimilated CO2 from the trickle‐bed reactor and also produced O2. With this bioreactor system, it was possible to efficiently remove volatile organic compounds (VOC) from the waste gases. Depending on the type of waste water investigated, elimination rates of 41% to 93% of BTEX (benzene, ethylbenzene, toluene, xylene) and 29% to 53% of VCH (volatile chlorinated hydrocarbons) were obtained. Due to the photosynthesis of the algae in the system's photoreactor, oxygen concentrations between 12% and 18% [v/v], equivalent to about 57% to 83% DOT, were obtained. This concentration permitted the aerobic degradation to be carried out without having to add fresh air. The trickle‐bed reactor and the photoreactor worked continuously, whereas the waste water in the stirred bioreactor was replaced in different batches. The accumulation of toxic compounds in the nutrient solutions of the trickle‐bed (EC‐50 > 30 g/l) and of the photoreactor (EC‐50 > 35 g/l) was low. Carbon dioxide concentrations in the gas flow were higher than in fresh air (1% to 3% [vol/vol]), but no long‐term accumulation of CO2 occurred. This means that the algae in the photoreactor were active enough to assimilate the CO2 which had been produced. They were also able to produce sufficient oxygen for aerobic hydrocarbon degradation. The system described is a first step towards treating waste gases which results from the bioremediation of hydrocarbon‐contaminated media in a closed gas circuit without any emission (e.g. VOC, CO2, germs).
Selection of hydroxyproline‐resistant cell lines from Solanum Tuberosum L. Callus. II. Plant regeneration and frost tolerance of regenerated plants
Authors: Anjum M. A. 
Published: December 2004

AbstractThe calluses of two hydroxyproline‐resistant lines (D20‐1 and D30‐1) of Solanum tuberosum L. were transferred to a solidified MS medium containing 1.0 mg/I IAA, 2.0 mg/l zeatin, 40.0 mg/l adenine sulphate, 1 g/l casein hydrolysate, 20 g/l sucrose and 10 g/l agar for plant regeneration. The shoot regeneration was only achieved from the callus of line D20–1. Regenerated shoots exhibited morphological variability. The degrees of frost tolerance were higher in the leaves of the regenerated plants compared with the leaves of the non‐selected control plants, but lower than that of the callus from which they were regenerated.
Separation of two dichlorprop/α‐ketoglutarate dioxygenases with enantiospecific properties from Comamonas acidovorans MC1
Authors: Müller R. H. , Babel W. 
Published: December 2004

AbstractComamonas acidovorans MC1, which is capable of degrading the chiral phenoxypropionate herbicides 2‐(2,4‐dichlorophenoxy)propionate [dichlorprop, (RS)‐2,4‐DP] and 2‐(4‐chloro‐2‐methylphenoxy)propionate [mecoprop, (RS)‐MCPP] and of degrading the phenoxyacetate herbicides 2,4‐dichlorophenoxyacetate (2,4‐D) and 4‐chloro‐2‐methylphenoxyacetate (MCPA), was investigated with respect to the enzymatic basis of this broad substrate specificity. The initial steps of the degradation pathway of (RS)‐2,4‐DP and 2,4‐D were studied. By applying either ion exchange chromatography or hydrophobic interaction chromatography it was possible to separate two enzyme fractions with etherolytic activity, which exhibited pronounced substrate specificity. One enzyme fraction was highly specific for the degradation of the R‐enantiomer of 2,4‐DP and did not essentially attack the S‐configuration. The other enzyme fraction showed pronounced activity toward the cleavage of the S‐enantiomer and additionally utilized 2,4‐D with almost equal velocity; (R)‐2,4‐DP was even cleaved at a low rate by this enzyme. These results confirm the existence of phenoxyalkanoatedegrading enzymes with enantiospecific properties in strain MC1.
Sanitization of immobilized biocatalysts for the production of 6‐aminopenicillanic acid
Authors: Nováčková J. , Plháčková K. , Sikyta B. 
Published: December 2004

AbstractFive different chemical reagents and γ‐rays were tested for the sanitization of immobilized biocatalysts with high penicillin G acylase (PGA) activity. The most effective chemical reagents were N‐cetyl‐N,N,N‐trimethylammonium bromide (CTAB) and 2‐isopropyl‐5‐methylphenol (thymol). The optimum concentration of CTAB for the treatment of the immobilized enzyme was 0.25% [w/v] and 1 h, for immobilized cells 0. [w/v] and 3 h. The optimum concentration of thymol for the immobilized enzyme was found to be 0.1% [w/v] and 1 h, for immobilized cells 0.27% [w/v] and 2 h. The optimum dose of γ‐rays for the sanitization of the immobilized enzyme was established as 3.2 kGy, for immobilized cells as 4.5 kGy.
Application of zeolites in the downstream processing of the character impact compound 2,5‐dimethyl‐4‐hydroxy‐furan‐3‐one (furaneol)
Authors: Pundsack E. , Scheper Th. 
Published: December 2004

AbstractThe purpose and scope of this article is to introduce capable zeolites into downstream processing of natural compounds, especially flavour compounds like 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furan‐3‐one (Furaneol®Furaeol is a registered trademark of FIRMENICH, Ch
). The synthesis and the recovery of Furaneol from L‐rhamnose are presented. Therefore adsorption isotherms of the zeolites ZSM5 and DAY with varying modules have been determined and adsorption experiments using model and reaction mixtures of Furaneol synthesis were performed and will be discussed.
Functionalized conducting polymers: Enhancement of the redox reversibility of polypyrrole by substituting polyether chains at the 3‐positions
Authors: Delabouglise Didier , Garnier Francis 
Published: December 2004

The performance of solid state batteries which employ conducting polymers as electrodes can be enhanced by the substitution of polyether chains onto the polymer backbone. The synthesis of pyrrole substituted in this manner (see Figure) is reported and the redox characteristics of the polymer based on this starting block described.magnified image
Ferroelectric liquid crystal with extreme polarization: X‐Ray structure analysis of the crystalline phase
Authors: Colquhoun Howard M. , Dudman Christopher C. , Robinson Gareth C. , O'Mahoney Caroline A. , Williams David J. 
Published: December 2004

Ciral liquid crystalline compounds which adopt the S phase are of interest as they can possess a spontaneous, permanent and macroscopic dipole moment (ferroelectric polarization) even in the absence of external fields. The compound reported here (see figure) has the highest known spontaneous polarization (520 nC cm−2) and therefore could improve the switching speeds of electro‐optic devices substantially.
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Dielectric spectroscopy: Fashionable again
Authors: Kremer Friedrich , Vallerien Sven U. , Zentel Rudolf 
Published: December 2004

The molecular dynamics of polymers and liquid crystals (see figure) affect the properties of these materials. The different modes of, for example, relaxation can be studied to great effect using a modern version of an old spectroscopic method—dielectric spectroscopy—which makes use of molecular dipoles to gain an insight into these processes.
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Synthesis of ceramic nanoparticles by the ultrasonic injection of an organosilazane precursor
Authors: Gonsalves Kenneth E. , Strutt Peter R. , Xiao Tongsan D. 
Published: December 2004

Communication: Ceramic and metallic materials with nanometer‐scale morphology possess novel properties important in nanoprecision manufacturing, where isotropic material properties are required in miniaturized components, and in the development of new composite materials with strengths approaching the theoretical limtis Unlike currently used methods for the synthesis of nanoparticles which can only produce small quantities, the new method reported here (see figure) which involves laser‐induced cross‐linking of a liquid silazane precursor to give Si3N4/SiC ceramics can yield up to 100 g/h.
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Surface resistance of thick film YBa2Cu3OX
Authors: Alford Neil McN. , Button Tim W. 
Published: December 2004

Research News: Radio‐frequency and microwave applications of high‐Tc superconductors (HTSC), for example delay lines (see figure) require films exhibiting a low surface resistance. A method has recently been developed for processing thick films of HTSC which results in a higher critical current density and lower surface resistance than previously achieved.magnified image