Ecological studies on hydrocarbon-oxidizing bacteria in Japanese coastal waters-X. Utilization of hydrocarbon substrates by heavy oil-degrading bacteria isolated from the sea water of oil-polluted Bisan Seto.

Abstract

Eighty one strains of heavy oil-degrading bacteria isolated from the sea water of oil-polluted Bisan Seto were tested for the ability to grow on four major groups of hydrocarbons, normal alkanes, branched alkanes, cyclo alkanes, and aromatic hydrocarbons, known to be present in heavy oils. The hydrocarbon substrates tested were n-hexadecane (as a representative normal alkane), pristane (2, 6, 10, 14-tetramethylpentadecane, as a representative branched alkane), cyclododecane (as a representative cyclo alkane), and low-molecular-weight polyaromatic hydrocarbon mixtures (fluorene plus anthracene plus pyrene). All of the bacteria demonstrated the ability of utilizing n-hexadecane and pristane but not cyclododecane and the aromatic hydrocarbons as a sole carbon source for growth. Using two representative strains of the bacteria, further degradation characteristics of normal alkanes of different chain length, pristane, and the aromatics were also studied. Results obtained in this study suggested that the degradation potential of normal alkanes and branched alkanes was considerably high in Bisan Seto, and also that cyclo-alkanes and polyaromatic hydrocarbons were much more resistant to microbial attack in this areas.