Showing papers on "Microbial biodegradation published in 1969"

Metabolism of heptachlor and its degradation products by soil microorganism.

Abstract: Chemical and soil microbial degradation of heptachlor proceeded by at least 3 pathways: epoxidation, hydrolysis, and reduction. Soil microorganisms converting heptachlor to its epoxide were identified. Thirty-five of 47 fungi, and 26 of 45 bacteria and actinomycetes isolated from soil produced the epoxide. In aqueous media, heptachlor hydrolyzed chemically to 1-hydroxychlordene, which the soil microorganisms were able to epoxidize to I-hydroxy. 2,3-epoxychlordenc. Heptachlor was dechlorinated by bacteria to chlordene which was then epoxidized to chlor dene epoxide. The insecticide and its byproducts were concentrated in the fungal mycelium. The presence of cyclodiene insecticides in the media appeared to influence some microbial metabolic processes.

Microbial Degradation Of Normal Paraffin Hydrocarbons In Crude Oil

Abstract: Experiments designed to measure the oxidation and degradation of crude oils by naturally occurring marine microorganisms are presently being conducted. Fifty active oil degrading cultures have been isolated in enriched seawater containing crude oil. Oil degradation has been determined with gas chromatography, wet combustion, and by measurement of surface tension. Normal paraffin hydrocarbons through C-26 are degraded by two different groups of micro organisms-those growing in the oil phase only and those growing in the aqueous phase. Emulsification of the crude oil through production of surfactants was observed in many of the enriched cultures. Microbial degradation of 35 to 55 per cent of oxidizable crude oil occurred within 60 hours.

Decomposition of petroleum products in our natural waters

Abstract: The overall objective of this investigation was to study the decomposition of crude and refined petroleum products in our natural waters. More specifically, the aims of this proposal were (1) to investigate the physical, chemical, and microbiological changes that occur in fresh and brackish water environments during the decomposition of crude and refined petroleum products and (2) to investigate the effects of the microbial byproducts on fish. The microflora caused marked physical changes in the oil under both aerobic and anaerobic conditions using both fresh water and artificial seawater. The disappearance of oil was more rapid under aerobic conditions and RQ values ranged from 0.4 to 0.6. A thin layer chromatographic technique was developed and employed to demonstrate chemical changes that occurred in the oil during microbial decomposition under all of the conditions employed. The addition of a nitrogen source and supplemental inorganic phosphate enhanced microbial activity. Waters in which the microbial degradation of oils had taken place were toxic for fish even after separation and removal of bacteria and oil. These data suggest that water-soluble products formed during the microbial decmposition of the petroleum products are harmful to fish.