bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of extracellular polysaccharides by a Rhizobium species from root nodules of Cajanus cajan
Authors: Datta C. , Basu P. S. 
Published: December 2004

AbstractThe 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

AbstractThe 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

AbstractThe 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.
Biodesulphurization of mengen lignite by Rhodoccocus rhodochrous in a batch stirred and aerated tank fermenter
Authors: Bayram Z. , Bozdemir T. , Durusoy T. , Yürüm Y. 
Published: December 2004

AbstractThe biodesulphurization of Mengen lignite by a mesophilic bacterium, Rhodococcus rhodochrus ATCC 53968, was investigated in a batch stirred and aerated reactor. The experiments were carried out at 28°C with an inoculum percentage, initial pH, initial sodium acetate and lignite concentration of the biodesulphurization medium of 8% [v/v], 6.5 mM, 20 mM and 20 g/l, respectively. Variations in the sulphur contents of the lignite relative to the biodesulphurization period were monitored. The effects of the stirring and aeration rates on the removal of different sulphur forms from coal were investigated in the ranges 450–1,200 rpm and 0.1–0.53 vvm and the optimum values were found to be 500 rpm and 0.18 vvm, respectively. An increase in the total sulphur reduction with increasing biodesulphurization time was observed. The maximum total sulphur removal percentage was found to be 15.2% at 1,200 rpm after four days of incubation. The highest total sulphur removal rate was calculated on the second day of microbial desulphurization for each run. The total and organic sulphur contents of the coal after biodesulphurization were correlated with the stirring and aeration rates by using the non‐linear least squares regression method. In the experimental runs lasting 8 days, the highest organic sulphur reducing percentage of 10.1% was obtained at a stirring rate of 500 rpm and an aeration rate of 0.40 vvm.
Production of extracellular polysaccharides by a Rhizobium species from the root nodules of Melilotus alba
Authors: Datta C. , Basu P. S. 
Published: December 2004

AbstractThe Rhizobium sp., isolated from the root nodules of the leguminous fodder herb Melilotus alba, produced large amounts of extracellular polysaccharides (EPS) (963.5 μg/ml) in a yeast extract mannitol medium. Growth and EPS production started simultaneously, but EPS production reached its maximum during the stationary phase of growth of the bacteria, at 20 hours. EPS production was increased with all of the thirteen sugars tested. Different nitrogen sources, such as nitrates, glutamic acid, casamino acid and L‐asparagine, increased the EPS production although it was inhibited by glycine, nitrite and ammonium salts. Among the vitamins and metal ions, only pyridoxal phosphate and ZnSO4 promoted EPS production. Attempts were made to optimize the cultural requirements for growth and maximum EPS production. Maximum EPS production (1457.0 μg/ml) was obtained when the medium was supplemented with glucose (1%), pyridoxal phosphate (2 μ g/ml), ZnSO4 × 7 H2O (10 μg/ml) and glutamic acid (0.1%). Under these conditions, the production was increased by 254.3% compared to the control. The EPS contained arabinose, xylose and rhamnose monomers. The presence of arabinose and xylose in the EPS produced by a Rhizobium sp. was uncommon.
Dynamic responses of biofilters to changes in the operating conditions in the process of removing toluene and xylene from air
Authors: Marek J. , Paca J. , Gerrard A. M. 
Published: December 2004

AbstractThe dynamic behaviour of biofilters intended to remove toluene and xylene from air was studied during transient states. Laboratory scale biofilters were filled with a mixture of peat, bark and wood and inoculated with a mixed microbial population. Toluene and xylene were applied both as single pollutants and as mixtures. Attention was focused on the evaluation of the following transients: the response of biofilters to step changes and peaks in pollutant concentrations, the effect of changes between single and multiple pollutant loadings and the response to shutdown periods.The biofilters demonstrated a good dynamic stability during transient states induced by change in inlet pollutant concentrations. Their time periods did not exceed three hours. No interaction between xylene and toluene degradation was observed during changes in loading with single pollutants or their mixture. The performance interruptions lasting less than 24 hours were found to have no significant influence on the removal efficiency of biofilters. When the biofilters were reacclimated after longer starvation periods, a short temporary decrease in efficiency whose minimum and duration were proportional to the length of a preceding shutdown period was observed. The longest starvation period (7 days) resulted in a reacclimation lasting 7 hours only. Adaptations of a microbial population to new operating conditions as well as sorption/desorption processes were suggested as the main factors influencing the dynamic reponse characteristics.
Improvement of the bioavailability of hydrocarbons by applying nonionic surfactants during the microbial remediation of a sandy soil
Authors: Löser C. , Seidel H. , Zehnsdorf A. , Hoffmann P. 
Published: December 2004

AbstractDuring the microbial treatment of a sandy model soil artificially contaminated with polycyclic aromatic hydrocarbons (PAHs), a large residual pollution was found. The remainig PAHs were sorbed into the micropores of the soil and were therefore not bioavailable. Using a lab‐scale precolator, the microbially pretreated soil was subjected to aftertreatment with surfactants with the aim of further degradation of its pollution. Two commercial nonionic surfatants of the polyethoxylate type, Präwozell F1214/5 N and Sapogenat T‐300, were used. The surfactants differ both in their physicochemical properties (CMC value, PAH solubilization capacity, adsorption onto soil) and in their microbial degradability. During aftertreatment under permanently aerobic conditions, only a weak PAH accumulation in the liquid phase was observed, which was due to a low solubilization rate as well as to simultaneous microbial degradation of the dissolved PAHs. Temporary anaerobiosis successfully suppressed the microbial degradation of both the surfactant and the solubilized PAHs, resulting in a more intensive PAH accumulation. But the PAH content of the soil ‐ the essential criterion for evaluating the efficiency of surfactant application ‐ was not decreased to a larger extent with surfactants than without them. To find out why the surfactants failed to act, the surfactant and hydrocarbon distribution among the liquid and solid phases was studied in mixtures of phenantherne‐spiked solis and Präwozell‐containig liquids; at heavy phenanthrene loading, the aqueous phase was saturated with PAH; at weak loading, it was unsaturated. Model‐aided data analysis showed that the soil may contain PAH in two fractions: strongly sorbed into soil pores and, in the case of heavy loading, also weakly attached to the soil surface. The latter is easily extractable, resulting in a PAH‐saturated liquid, while strongly adsorbed PAH is only partially dissolved due to competition between the micelles and the soil pores for the PAH. The microbially pretreated soil contains only strongly bound PAHs, which are as difficult to extract by surfactants as they are poorly accessible for microbes.
Influence of crude oil contamination on the bacterial community of semiarid soils of Patagonia (Argentina)
Authors: Pucci O. H. , Bak M. A. , Peressutti S. R. , Klein I. , Härtig C. , Alvarez H. M. , Wünsche L. 
Published: December 2004

AbstractAutochthonous bacteriocenoses in semiarid soils in Patagonia were found to be capable of rapidly adapting to high contamination with crude oil. This adaptation at community level is due to the selective enrichment of hydrocarbon‐utilizing bacteria always present in these soils. Immediately after a heavy contamination with crude oil, the authochthonous bacteriocenosis contained about 28% hydrocarbon‐utilizing bacteria which could be classified into eight ecotypes with characteristic metabolic profiles. Mainly n‐alkanes were used as growth substrates of representative strains. After seven months' exposure to crude oil, the bacteriocenosis consisted almost entirely of hydrocarbon‐utilizing bacteria. At least fourteen ecotypes were distinguishable, and the majority of representative strains were able to metabolize a broad spectrum of aliphatic and aromatic hydrocarbons. Corresponding to the significant alteration of the physiological diversity, drastic changes to the taxonomic diversity were also found. Whereas at the beginning of the study the autochthonous bacteriocenoses were dominated by GRAM‐positive genera of the Actinomycetales (Dietzia, Gordona, Nocardia, Rhodococcus, Streptomyces) with high ecological potency, after just two months' exposure to crude oil, GRAM‐ negative bacteria (especially Pseudomonas stutzeri) became predominant within the hydrocarbon‐utilizing bacteriocenoses accompanied by some GRAM‐positive genera of the Actinomycetales with a significantly lower abundance. These findings underline the importance of Pseudomonas and some genera of Actinomycetales for processes of natural attenuation and the technically supported in situ bioremediation of soil polluted by crude oil in Patagonia.
Variation revealed by RAPD‐PCR profiles of microsymbiont Anabaena azollae strains from four N2 fixing Azolla cultures
Authors: Subhashini R. , Kumar K. , Kannaiyan S. 
Published: December 2004

AbstractNitrogen fixing Anabaena azollae strains isolated from four different Azolla cultures were characterized based on their total protein profile and RAPD profile to study the existing variation among them. As expected, the isolates showed almost similar protein banding patterns, but exhibited differences in 40–70 KDa protein subunits. Polymerase chain reaction of the DNA of the isolates, using four different primers, amplified specific sequences of DNA and showed clear polymorphism among the isolates. The RAPD profile generated the fingerprinting pattern characteristic of each strain based on the sequence of the primers used. Common band sharing observed between the strains A. azollae‐RS‐KK‐SK‐AM and A. azollae‐RS‐KK‐SK‐RP probably represents maternal inheritance of DNA to the progeny. The polymorphic bands were generated specifically for the isolates A. azollae‐RS‐KK‐SK‐RP and A. azollae‐RS‐KK‐SK‐AM with primers numbered 2 and 4, respectively, which could be developed as possible markers for these isolates.
Development of transgenic rice pure lines by particle bombardment‐mediated transformation and genetic analysis‐based selection
Authors: Tang K. , Wu A. , Yao J. , Qi H. , Lu X. 
Published: December 2004

AbstractMature seed‐derived callus from an elite Chinese japonica rice cv. Eyl 105 was transformed with a plasmid containing the selectable marker hygromycin phosphotransferase (hpt) and the reporter β‐glucuronidase (gusA) genes via particle bombardment. After two rounds of selection on hygromycin (30 mg/l)‐containing medium, resistant callus was transferred to hygromycin (30 mg/l)‐containing regeneration medium for plant regeneration. Twenty‐three independent transgenic rice plants were regenerated from 127 bombarded callus with a transformation frequency of 18.1%. All the transgenic plants contained both gusA and hpt genes, revealed by PCR/Southern blot analysis. GUS assay revealed 18 out of 23 plants (78.3%) proliferated on hygromycin‐containing medium had GUS expression at various levels. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From R2 generations with their R1 parent plants showing 3:1 Mendelian segregation, we identified three independent homozygous transgenic rice lines. The homozygous lines were phenotypically normal and fertile compared to the control plants. We demonstrate that homozygous transgenic rice lines can be obtained via particle bombardment‐mediated transformation and through genetic analysis‐based selection.
Formation of aminium lactates in lactic acid fermentation. Fermentative production of 1,4‐piperazinium‐(L,L)‐dilactate and its use as a starting material for the synthesis of dilactide (Part 2)
Authors: Kamm B. , Kamm M. , Richter K. , Reimann W. , Siebert A. 
Published: December 2004

AbstractA fermentation process for manufacturing 1,4‐piperazinium‐(L,L)‐dilactate from renewable raw materials and a method for processing this product into L,L‐dilactide are described. Lactic acid fermentation with Lactobacillus paracasei was modified in such a way that pH control occurred by using an aqueous solution of piperazine as a correcting agent instead of sodium hydroxide solution. The production of a stoichiometrically composed piperazinium lactate was possible when the pH was 5.0. From 5.0 kg of glucose and 2.15 kg of piperazine, 6.65 kg of 1,4‐piperazinium‐(L,L)‐dilactate were formed in the fermentation process. Separation from fermentation broth, purification and concentration of the product in aqueous solutions were carried out by means of ultrafiltration, nanofiltration and electrodialysis. Total product retention by the membranes used was about 33%. The crystalline salt was obtained by vacuum evaporation. Processing of the 1,4‐piperazinium‐(L,L)‐dilactate into L,L‐dilactide was performed in a special glass reactor. A product yield of 70% was achieved. The purified product was characterized by elementary analysis, as well as solubility behaviour, polarity and spectroscopic data. An overall process consisting of the stages fermentation, purification and concentration of piperazinium dilactate as well as cyclization of the latter to dilactide is described.
Investigation into the biotechnological modification of wood and its application in the wood‐based material industry
Authors: Unbehaun H. , Dittler B. , Kühne G. , Wagenführ A. 
Published: December 2004

AbstractBecause of the growing utilization of renewable raw materials, the technical use of lignocellulosic fibres from wood and other annual plant materials is becoming increasingly important. The conventional production process of fibreboards is characterized by high‐energy consumption and use of ecologically insecure synthetic lesins. Approximately 40 to 45% of the total energy expenditure are used for the thermo‐mechanical pulping. Because of high plastication temperatures, an inactive lignin crust on the fibre surface is formed. For that reason, for glueing of the fibres, urea formaldehyde and melamin resins are usually used. The costs for the resin amount to approximately 50% of the entire material costs. In addition, environmental problems are caused. The aim of our investigation is the reduction of energy and resin consumption by enzymatic modification of wood chips and the enzymatic activation of the inherent bonding strength of the material. The first industrial use of fungi for the modification of wood was in the production of “Myco wood”. Pleurothus ostreatus and Trametes versicolor were applied for nonsterile delignification of beech wood. The present investigation of the authors deals with the mycological pre‐treatment of wood chips in order to reduce the energy consumption during wood pulping. The screening results favour the brown rotter Gleophyllum trabeum for pinewood (Pinus silvestris) and the white rotter Trametes hirsuta for beech (Fagus silvatica). Both species show resistance against mould fungi. The use of submerged inoculum of these fungi has the advantage over wheat inoculum that the lag phase is less than 12 hours and that the addition of nutrients or fungicides is not necessary. Short‐time wood chip incubation results in a 40% decrease of energy consumption during thermo‐mechanical pulping and in improved fibreboard properties. Lignin reduction could not be determined by gravimetrical and x‐ray microanalysis.Comparative investigations of fibre incubation using laccase, a submerged culture of Trametes versicolor and rape straw fibres show a high increase in bending and tensile strength and an improvement in the hygroscopic properties of glue‐free fibre boards for the last two incubation kinds. Similar effects have been obtained incubating pine wood fibres for the production of fibre sheets with enzyme medium of Trichoderma reseei.
Functionalized Conducting Polymers—Towards Intelligent Materials
Authors: Garnier Francis 
Published: December 2004

AbstractOrganic conjugated polymers and oligomers constitute a three‐dimensional network of molecular wires, in which all monomeric units can be functionalized with various prosthetic groups. By varying the nature of these groups, specific interactions with external physical or chemical phenomena can be developed in these materials, leading to molecular devices such as sensors, transducers, memories and logic operators. Chemists have already mastered the realization of many of these functional elements, which mimic those existing in organized beings. The further assembly of these elements in multifunctionalized organic conducting polymers and oligomers will represent the next step towards intelligent materials.
X‐ray techniques using synchrotron radiation in materials analysis
Authors: Lengeler Bruno 
Published: December 2004

AbstractThe extraordinary properties of SR have opened up new horizons for all techniques which use vacuum ultraviolet light and X‐rays. In this article, some applications of SR in materials science have been discussed. X‐ray absorption spectroscopy is a local, atom specific probe of the geometrical and electronic structure of the absorbing species. As an example, the lattice site location and the valence of Co in a doped high‐Tc, superconductor YBa2Cu2–5Co0–5O7–4 has been discussed.
Advanced materials for reversible optical storage
Authors: Engler Edward M. 
Published: December 2004

The development of semiconductor lasersand the application of materials such as garnets as the recording media have led to fast progress in optical storage technology. The ability of the new methods (for mode of information storage see figure) to compete with magnetic storage are discussed, new materials are assessed, and techniques such as direct overwrite through field or laser modulation are described.magnified image
Silica surface sensitization and chemical sensors
Authors: Clechet Paul , Jaffrezic‐Renault Nicole 
Published: December 2004

AbstractThe surface modification of materials and its control now appear to be a challenge in many fields of technology, for example, composites, chromatography, and chemical sensors.A well controlled engineering process for producing self‐assembled long chain monolayers on a thin thermal silica layer has been perfected in our laboratory. The monolayers are covalently bonded to SiO2/Si(100) heterostructures and have been chemically (chemical analysis, pH sensitivity) and physically (spectroellipsometric and capacitance measurements) characterized.The application of this process for sensitizing the surface of the silica insulator used in CHEMFET chemical sensors is presented using the example of an Ag® sensitive device. The main features of this sensor are its short response time(< 2 s) and its long lifetime (> 3 months).
Triphenyl methane dyes as sensor materials for solvent detection with surface‐acoustic‐wave devices
Authors: Dickert Franz L. , Bertlein Gerhard , Mages Gert , Bulst Wolf‐E. 
Published: December 2004

Highly‐colored phthalide carbenium ions (see figure) embedded in a matrix of phenols can form the basis of solventsensing devices able to detect a variety of solvents in concentrations down to a few ppm. Solvent absorption disturbs hydrogen bonding producing a less favorable environment for the cations, the changing concentration of which can be monitored using optical absorption, or SAW‐devices.magnified image