Degradation of petroleum hydrocarbons by oil field isolated bacterial consortium

Abstract

A mixed consortium was prepared with 15 bacteria isolated by enrichment technique from the sample collected from an oil contaminated site. This consortium was incubated with crude oil to investigate the metabolic capability of bacteria. The degradation efficiency of the isolates in consortium was checked with 2% crude oil by shake flask transformation in mineral salt medium, at 37°C for 24 days. Total removal of aliphatic and aromatics was 94.64% and 93.75% respectively. Among the various components of the crude oil degradation by the bacterial consortium, the biotic removal of alkanes was maximum, 90.96% for tridecane (C₁₃) followed by pentadecane (C₁₅) at 77.95%, octadecane (C₁₈) at 74.1%, while other alkanes showed 56 to 69% after 24 days of incubation. The aromatics (benzene, toluene and xylene) were vaporized in the 4th day of incubation, while the efficiency on polyaromatic fractions (anthracene, phenanthrene and pyrene) was 46.17 to 55.3% after 24 days. The ability of degrading long chain n-alkanes and crude oil at high concentrations makes the consortium potentially useful for bioremediation and microbial enhanced oil recovery.

Key words: Consortium, petroleum hydrocarbons, crude oil, aliphatics, aromatics.