Abstract: The phenol degradation by Candida sp. and Pseudomonas sp. immobilized on activated carbon was investigated. Thanks to its great adsorptive surface, activated carbon is suited as supporting material for microorganisms and also provides a high adsorption capacity for phenol.

Abstract: A negative correlation between adsorption of low molecular weight organic acids and sugars onto a hydroxyapatite surface and biodegradation rates of the compounds in the presence of the mineral was observed. Qualitatively, the effect was the same whether the organics were equilibrated with the surface prior to the addition of organisms or the organisms were preattached to the surface. Glucose, acetic acid, succinic acid, glutamic acid, and citric acid showed equilibrium adsorption values ranging from 0–94% from a 2μM solution. Changes in both respiration and assimilation of the substrates in the presence of hydroxyapatite were inversely correlated with adsorption.

Abstract: The metabolism of phenol and various chlorophenols was studied in groundwater aquifer microcosms. Flow-through column microcosms containing pristine aquifer material were used to assess aerobic biodegradation processes. Reductive metabolism of the substrates was studied in serum bottles filled with aquifer material contaminated by municipal landfill leachate. We found that microorganisms present in an actively methanogenic aquifer were able to metabolize chlorophenols by replacing the halogen substituents with hydrogen atoms. The identity of the dehalogenated intermediates was confirmed by mass spectrometry for a model substrate and by cochromatography for others. Complete removal of the aryl halides was necessary before the phenol intermediate could be mineralized to methane and carbon dioxide. However, the chlorophenols tended to persist in anoxic microcosms containing material from the same aquifer but from a non-methanogenic site. Metabolism and acclimation of chlorophenols and phenol was noted in aerobic microcosm studies, but the degradation pathway(s) were not established.

Abstract: Contaminating amounts of certain halogenated aliphatic hydrocarbons are degraded and removed from water such as drinking water and industrial waste water, by treatment of the water with a microorganism that is effective to metabolize gaseous hydrocarbons by the action of monooxygenase enzyme.

Abstract: [14C-lignin]lignocellulose was solubilized by alkaline heat treatment and separated into different molecular size fractions for use as the sole source of carbon in anaerobic enrichment cultures. This study is aimed at determining the fate of low-molecular-weight, polyaromatic lignin derivatives during anaerobic degradation. Gel permeation chromatography was used to preparatively separate the original 14C-lignin substrate into three component molecular size fractions, each of which was then fed to separate enrichment cultures. Biodegradability was assessed by monitoring total carbon dioxide and methane production, evolution of labeled gases, loss of 14C-activity from solution, and changes in gel permeation chromatographic elution patterns. Results indicated that the smaller the size of the molecular weight fraction, the more extensive the degradation to gaseous end products. In addition, up to 30% of the entire soluble lignin-derived carbon was anaerobically mineralized to carbon dioxide and methane.

Abstract: The activated sludge biodegradability of 12 commercial phthalate esters was evaluated in two test systems: (i) a semicontinuous activated sludge test and (ii) an acclimated 19-day die-away procedure. Both procedures demonstrated that phthalate esters are rapidly biodegraded under activated sludge conditions when loss of the parent phthalate ester (primary degradation) is measured.

Abstract: The requirements and conditions for pentachlorophenol (PCP) biodegradation by a mixed bacterial culture was studied. The effects of oxygen, nutrients, additional carbon sources, pH and temperature are described. Up to 90% of PCP was degraded into CO2 and inorganic chloride in 1 week at an input concentration of <600 μM. Degradation continued when pO2 was lowered to 0.0002 atm but ceased when pO2 was further decreased to 0.00002 atm. Supplementary carbon sources, such as phenol, hydroxybenzoic acids or complex nutrients did not affect the biodegradation, but the presence of ammonium salts enhanced the rate of PCP degradation without affecting the yield of CO2. The degrading organisms were shown to be procaryotic mesophiles; no degradation was shown at temperatures below +8° and above +50°C. The optimum pH for degradation was from 6.4 to 7.2 and at higher pH value (8.4) degradation was inhibited more than at lower pH (5.6).

Abstract: The biodegradation of fatty alcohol polyglycol ethers was studied by analyzing the 14C-labeled intermediates isolated from the effluent of a model continuous-flow sewage treatment plant after dosage of either alkyl- or heptaglycol-labeled stearyl alcohol ethoxylate (SA-7EO). In each case, uncharged and carboxylated (mainly dicarboxylated) polyethylene glycols constituted the most prominent metabolites. The results indicate that there is a faster degradation of the alkyl than the polyethylene glycol moiety and that there are two distinct primary degradation mechanisms acting simultaneously in microbial biocenoses: intramolecular scission of the surfactant as well as omega- and beta-oxidation of the alkyl chain. Characterization of the bulk of 14C-labeled metabolites as a homologous series of neutral and acidic polyglycol units and identification of several C2-fragments accounted for the depolymerization of the hydrophilic part of the surfactant by stepwise cleavage of ether-bound EO units; from additional degradation studies employing either neutral or carboxylated 14C-labeled polyethylene glycols as model metabolites, it was concluded that hydrolytic as well as oxidative cleavage of C2-units is involved. Most of the identified low-molecular-weight 14C-labeled acids suggest an ultimate degradation of EO monomers by the oxidative dicarbonic acid cycle or the glycerate pathway or both. In addition, the finding of considerable amounts of oxalic and formic acids allow consideration of an additional mineralization route via glyoxylic, oxalic, and formic acids. The simultaneous action of different degradation mechanisms indicates the involvement of several distinct bacterial groups in the biodegradation of fatty alcohol ethoxylates under environmental conditions.

Abstract: The influence of readily degradable, naturally occurring carbon substrates on the biodegradation of several monosubstitued phenols (m-cresol, m-aminophenol, p-chlorophenol) was examined. The natural substrate classes used were amino acids, carbohydrates, and fatty acids. Samples of the microbial community from Lake Michie, a mesotrophic reservoir, were adapted to different levels of representatives from each natural substrate class in chemostats. After an extended adaptation period, the ability of the microbial community to degrade the monosubstituted phenols was determined by using a radiolabeled substrate uptake and mineralization method. Several microbiological characteristics of the communities were also measured. Adaptation to increasing concentrations of amino acids, carbohydrates, or fatty acids enhanced the ability of the microbial community to degrade all three phenols. The stimulation was largest for m-cresol and m-aminophenol. The mechanism responsible for the enhancement of monosubstituted phenol metabolism was not clearly identified, but the observation that adaptation to amino acids also increased the biodegradation of glucose and, to a lesser extent, naphthalene suggests a general stimulation of microbial metabolism. This study demonstrates that prior exposure to labile, natural substrates can significantly enhance the ability of aquatic microbial communities to respond to xenobiotics.

Abstract: A range of fungi isolated from decomposing straw were compared for their ability to grow on straw and its components. Extension rates were measured on agar containing water-soluble extract and on straw internodes. Activity was measured by clearing of cellulose and weight loss from straw. Penetration of fungi into the lumen of sterile wheat straw was also determined. In all the tests Sordaria alcina and Trichoderma harzianum showed outstandingly high growth and activity. In respiratory measurements on inoculated straw, Chaetomium globosum showed the greatest activity.

Abstract: The degradation of 4-chlorophenol by free and by Ca-alginate-immobilized cells ofAlcaligenes sp A 7-2 has been studied Increasing concentrations of 4-chlorophenol (04–055 mM) were better tolerated and more quickly degraded by the immobilized organisms than by free cells The capability for haloarene-degradation is inducible In semicontinuous fermentation at pH 7 a minimal degradation time of 5 h for degrading 02 mM 4-chlorophenol was reached Fermentation temperature was shown to be important for inducing the degradation capability, but to be less important for the degradation rate by induced organisms High-frequency feeding of small amounts of 4-chlorophenol (005 mM) was more favourable than low-frequency feeding of larger amounts (015 mM)

Abstract: Several bacterial strains that can oxidize mono- and dichlorinated biphenyls with one unsubstituted ring have already been described. The major route for this biodegradation leads ultimately to the corresponding chlorobenzoic acid, but several other minor chlorinated metabolites that might possibly be of concern for the environment have also been described previously. Since none of the bacterial strains that are able to oxidize these chlorinated biphenyls in pure culture are known to degrade chlorobenzoic acid, the oxidation of these substrates by axenic cultures always generates chlorobenzoates plus several other metabolites. In the present study, we have estimated the biodegradation of 4-chlorobiphenyl (4CB) by a two-membered bacterial culture containing one strain able to grow on 4CB and to transform it into 4-chlorobenzoate (4CBA) and one strain able to degrade 4CBA. The results were encouraging, since it was shown that the degradation of 4CB was more rapid and complete with the double bacterial culture.

Abstract: Veratrylglycerol-beta-guaiacyl ether (0.2 g/liter), a lignin model compound, was found to be degraded by mixed rumen bacteria in a yeast extract medium under strictly anaerobic conditions to the extent of 19% within 24 h. Guaiacoxyacetic acid, 2-(o-methoxyphenoxy)ethanol, vanillic acid, and vanillin were detected as degradation products of veratrylglycerol-beta-guaiacyl ether by thin-layer chromatography, gas chromatography, and gas chromatography-mass spectrometry. Guaiacoxyacetic acid (0.25 g/liter), when added into the medium as a substrate, was entirely degraded within 36 h, resulting in the formation of phenoxyacetic acid, guaiacol, and phenol. These results suggest that the beta-arylether bond, an important intermonomer linkage in lignin, can be cleaved completely by these rumen anaerobes.

Abstract: Description de la biodegradation de ce colorant par les levures rouges oxydatives (Rhodotorula sp. et Rhodotorula rubra). Role des levures et des champignons inferieurs semblables aux levures dans l'elimination des contaminants de l'environnement. Etude de la souche fermentative S. Cerevisiae comme mutant pour les futures etudes sur les colorants

Abstract: Thermophilic (55 degrees C) anaerobic enrichment cultures were incubated with [C-lignin]lignocellulose, [C-polysaccharide]lignocellulose, and kraft [C]lignin prepared from slash pine, Pinus elliottii, and C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31 to 37% of the pine polysaccharides and 56 to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10 to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds.

Abstract: Structure/reactivity relations are investigated experimentally and theoretically for the microbial degradation of 35 substituted phenols and anilines by adapted mixed cultures of bacteria. From the results one can conclude that the initial attack of the aromatic nucleus has an electrophilic character and is ratelimiting. The results are suitable for predictions of biodegradation rates of organic compounds and facilitate understanding of the mechanism of degradation.

Abstract: Mixed cultures of bacteria grew in medium containing real s-triazine wastes as nitrogen source. About 80% of the s-triazine waste could be degraded as determined by HPLC and by measurements of dissolved nitrogen. The culture required an added carbon source in order to degrade s-triazines. A temperature optimum near 40C was observed and a salt concentration above about 4% markedly retarded growth and the degradation of s-triazines. This system was examined as a biological treatment for wastes from syntheses of s-triazines.

Abstract: Microorganisms have been isolated from a biodegraded crude oil from the Gifhorn trough, Lower Saxony. A non-degraded crude oil, related to the same source rock as the biodegraded one, was inoculated with the microorganisms found and the course of biodegradation thus initiated was followed by gas and liquid chromatographic techniques. The influence of biodegradation on commonly used oil-to-oil correlation parameters was investigated in detail.