Showing papers on "Microbial biodegradation published in 1984"

Microbial degradation of organic compounds.

Abstract: 16 contributions by various authors. Degradative pathways. Chemical characterisation of biodegradation. C1 compounds transformation. Aliphatic compounds. Alcyclic rings. Aromatics hydrocarbons. Furans, tiophenes, halogenated aromatic compounds. Phtalates. Lignin. Significance of microbial communities. -- ICCROM

Microbial biodegradation of 4-chlorobiphenyl, a model compound of chlorinated biphenyls. [Achromobacter; Bacillus brevis]

Abstract: The biodegradation products of 4-chlorobiphenyl were analyzed in an Achromobacter sp. strain and a Bacillus brevis strain. Both strains generated the same metabolites, with 4-chlorobenzoic acid as the major metabolic product. The authors' results corroborate previous observations whereby most bacterial strains degrade the chlorobiphenyls via a major pathway which proceeds by a hydroxylation in position 2,3 and meta-1,2 fission. However, they also detected several metabolites whose structure suggests the existence of other routes for the degradation of chlorinated biphenyls. 21 references.

Microbial biodegradation of 4-chlorobiphenyl, a model compound of chlorinated biphenyls

Abstract: The biodegradation products of 4-chlorobiphenyl were analyzed in an Achromobacter sp. strain and a Bacillus brevis strain. Both strains generated the same metabolites, with 4-chlorobenzoic acid as the major metabolic product. Our results corroborate previous observations whereby most bacterial strains degrade the chlorobiphenyls via a major pathway which proceeds by an hydroxylation in position 2,3 and a meta-1,2 fission. However, we also detected several metabolites whose structure suggests the existence of other routes for the degradation of chlorinated biphenyls.

Microbial degradation of alkyl carbazoles in Norman Wells crude oil

Abstract: Norman Wells crude oil was fractionated by sequential alumina and silicic acid column chromatography methods. The resulting nitrogen-rich fraction was analyzed by gas chromatography-mass spectrometry and showed 26 alkyl (C1 to C5) carbazoles to be the predominant compounds. An oil-degrading mixed bacterial culture was enriched on carbazole to enhance its ability to degrade nitrogen heterocycles. This culture was used to inoculate a series of flasks of mineral medium and Norman Wells crude oil. Residual oil was recovered from these cultures after incubation at 25°C for various times. The nitrogen-rich fraction was analyzed by capillary gas chromatography, using a nitrogen-specific detector. Most of the C1-, C2-, and C3- carbazoles and one of the C4-isomers were degraded within 8 days. No further degradation occurred when incubation was extended to 28 days. The general order of susceptibility of the isomers to biodegradation was C1 > C2 > C3 > C4. The carbazole-enriched culture was still able to degrade n-alkanes, isoprenoids, aromatic hydrocarbons, and sulfur heterocycles in the crude soil.

Inhibitory interactions of aromatic organics during microbial degradation

Abstract: Phenol, benzene and naphthalene were exposed, both singly and in combination, to oil refinery settling pond inocula. Although all three aromatic organics degraded rapidly when dosed singly, benzene and naphthalene were not metabolized in the presence of phenol. These results illustrate the difficulty of predicting environmental fates of complex chemical mixtures.

Microbial Biodegradation of 2,4,5-Trichlorophenoxyacetic Acid and Chlorophenols

Abstract: Maintaining the carbon, nitrogen, and sulfur balances in the environment is one of the main tasks of microorganisms in nature; microorganisms degrade most compounds so that their basic elements can be recycled. However, naturally occurring chlorinated hydrocarbons are rather rare (25). Chlorinated synthetic chemicals such as PCBs, dichloro-diphenyl-trichloro-ethane (DDT), and 2,4,5-T, generally are degraded only slowly (20,23,24), mostly through co-oxida-tive metabolism (1,23), The persistence of these compounds is thought to be due to a lack of the ability of microbial cells to derive their energy and cellular constituents from the oxidative metabolism of these compounds (1), Persistence of chemicals in nature will amplify our pollution problems as time progresses, so that even what seems like an insignificant amount of a given chemical, if applied repeatedly, will accumulate until its environmental impact is felt.

Ground water pollution by organic solvents and their microbial degradation products

Abstract: Serious contamination of the ground water at a depth of about 30 m beneath a paint factory was found to have occurred as a result of the dispersion of organic solvents from a number of underground storage tanks Samples of water in static and in dynamic conditions were taken from a well excavated to a depth of about 61 m close to the probable source of the pollution Extraction with methylene chloride on a 100 ml water sample at various pH values yielded three fractions The basic fraction was found to contain no significant traces of organic compounds, whilst the neutral fraction revealed considerable quantities (several tens of ppm) of various organic solvents commonly used in this kind of industry These were hydrocarbons, prevalently aromatic, alcohols, glycol ethers, ketones, esters, alkyl halides Other oxygenated compounds were also found to be present; these were alcoholic or ketonic, aliphatic or aromatic in nature, and their presence could hardly be ascribed to dispersions from the industry responsible for the pollution Aliphatic and aromatic acids and alkyl phenols, which could not be explained by the products used in the factory, were also found in the acidic fraction The presence of all these substances was attributed to oxidative microbial degradation of the hydrocarbon components present in the soil and water, which hypothesis was supported by the presence in the water samples of a large number of microorganisms capable of oxidizing aromatic hydrocarbons