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

Abstract.

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.