Isolation and characterization of a bacterium that produces hydrocarbons extracellularly which are equivalent to light oil.

A halotorelant bacterial strain that produces a significant amount of lipids from short-chain fatty acids was isolated from the sludge of a sewage disposal plant. This strain displayed a significant extracellular accumulation of lipids. The yield of lipids including hydrocarbons was highest (120% of cell dry weight) at the end of the linear growth phase. Fractionation of the lipids using thin-layer chromatography and subsequent gas chromatography showed that hydrocarbons were also obtained following an increase in total lipids. Their yield was the highest (50% of cell dry weight) in the linear growth phase. Additional analysis using infrared absorption spectrum and gas chromatography-mass spectrometry showed that the hydrocarbon fraction was composed of alkanes, such as C15H32, C18H38, C21H44, C22H46 and C24H50. Homology analysis of the 16s rDNA sequence as well as studies of the morphological and physiological characteristics indicated that the bacterium is a strain of Vibrio furnissii.