The diversity of alkane degrading bacteria in the enrichments with deep sea sediment of the South China Sea

Abstract:

Deep sea sediment samples of the South Sea of China were used for isolation and biodiversity examination of hydrocarbon degrading bacterium. 48 isolates were obtained from the enrichments with hexadecane as the sole carbon sources. Among them，27 isolates were capable of degrading alkane; and 4 could produce biosurfactant significantly as determined by the surface tension measurement. 2 isolates belonging to Dietzia maris lowered water surface tension to 33 mN/m. This is the first report about D. maris in biosurfactant production. The results of polymerase chain reaction (PCR) followed by Denaturing Gradient Gel Electrophoresis (DGGE) and DNA sequencing suggested that Bacillus was the dominant member in the hexadecane enriched communities. Isolates of Bacillus aquimaris were demonstrated to be the most predominant degraders in all 7 samples at 2 sampling sites. In addition, Sporosarcina， Halomonas and Brevibacterium were also found as one of the dominant members in some samples. Therefore，species of Bacillus might play an important role in alkane degradation in the sediments of the sampling sites.

Key words:South China Sea; deep-sea sediment; alkane-degrading bacteria; biodiversity; biosurfactant