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HYDROCARBON DEGRADATION BY MARINE BACTERIA: SCREENING AND GENETIC MANIPULATION

SHEIKH AJAZ RASOOL, SAMREEN IJAZ AND SYED ABDUS SUBHAN

Abstract: Forty marine bacterial isolates from Karachi coast were screened for hydrocarbon degradation. All the three solid hydrocarbons (biphenyl, naphthalene and phenanthrene) were degraded by 63% of the marine isolates, two were degraded by 25%, while one was degraded by 8% of these bacteria. The five liquid hydrocarbons (benzene, heptane, octane, toluene and xylene) were degraded by 13% of the marine isolates, while 27% isolates could degrade four hydrocarbons. About 10% marine isolates degraded all the solid and liquid hydrocarbons, whereas 3% could not utilize any form of hydrocarbon. Location of the genetic determinants responsible for degradation was determined by acridine orange mediated curing (plasmid elimination). Hydrocarbon degradation potential was lost after such curing thereby establishing the control of hydrocarbon degradation by plasmid-borne genes. These extrachromosomal plasmid-borne genes were stably transferred to the genuine competent and the cured (donor converted) recipient cells. Interestingly, the transconjugants also acquired the gene transfer potential to other prospective recipients.
 

Department of Microbiology, University of Karachi, Karachi, Pakistan.