Ecological studies on hydrocarbon-oxidizing bacteria in Japanese coastal waters - VIII. Characterization and oil-degrading activity of heavy oil-degrading bacteria isolated from the sea water of oil-polluted Bisan Seto and oil-unpolluted Hibiki Nada.

Abstract

The flora of heavy oil-degrading bacteria isolated from water samples collected in oil-polluted Bisan Seto and oil-unpolluted Hibiki Nada was investigated. The oil-degrading activity of the isolated strains was also measured. It was observed that coryneforms were exclusively dominant among oil-degrading isolates in oil-polluted Bisan Seto. In oil-unpolluted Hibiki Nada, coryneforms and Pseudomonas were isolated in the same ratio. Oil-degrading activity of coryneforms was much higher than that of Pseudomonas, regardless of where they were isolated. From these results, it was suggested that coryneforms play an important role in the biodegradation of oil in oil polluted Biasn Seto. When the average oil-degrading activity of the strains isolated from Bisan Seto and that from Hibiki Nada was compared, the former (21.6%) was significantly higher than the latter (14.1%).It was suggested that the flora and oil-degrading activity of oil-degrading bacteria were sensitive indicators of oil-pollution than other factors previously examined (i.e. numbers of oil degrading bacteria, the ratio of the degraders to the total heterotrophs).