Aerobic biodegradation of hopanes and norhopanes in Venezuelan crude oils
نویسندگان
چکیده
The microbial degradation of two Venezuelan crude oils enriched in 25-norhopanes was examined after a 5-week aerobic incubation using a microbial enrichment culture. Analysis of the oils using gas chromatography±mass spectrometry revealed degradation of the C28 tricyclic terpane, the C29±C34 17a(H),21b(H)-hopanes, and the C29 17a(H),21b(H)-25-norhopane. The C35 17a(H),21b(H)-hopane and 18a(H)-oleanane were conserved. Further, the C28± C34 17a(H),21b(H)-25-norhopanes were degraded and no formation of 25-norhopanes was observed. Degradation caused preferential removal of the 22R versus the 22S isomer in both the extended hopanes and 25-norhopanes, implying that bacteria remove these compounds in aerobic environments. These data demonstrate 25-norhopane degradation on a time scale similar to that for other biomarkers. # 2001 Elsevier Science Ltd. All rights reserved.
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Stereoselective biodegradation of tricyclic terpanes in heavy oils from the Bolivar Coastal Fields, Venezuela
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