[Identification and characterization of a novel hydrocarbon-degrading Marinobacter sp. PY97S].

OBJECTIVE

To identify and characterize a hydrocarbon-degrading bacterium isolated from the sediment of the Yellow Sea.

METHODS

We used 16S rRNA gene sequences based phylogenetic analysis, physiological and biochemical characterization, DNA G + C content assaying, determination of cellular fatty acids, testing of carbon sources and respiratory lipoquinone and experiment of DNA-DNA relatedness. Its capability of degrading aliphatic hydrocarbons in ONR7a media supplemented with nine n-alkanes, separately, as sole source of carbon and energy was further determined.

RESULTS

The Gram-negative isolate PY97S was a member of the genus Marinobacter, catalase-and oxidase-positive, and with Q-9 as its predominant respiratory lipoquinone. The similarity between its 16S rRNA gene and that of its most closely related type strain in GenBank Marinobacter koreensis DD-M3(T) was 96.93%, and their level of DNA relatedness was 46.7%. The appropriate temperature for its growth ranged from 15 degrees C to 35 degrees C with the optimum of 30 degrees C, the appropriate initial acidity from pH 6.0 to 9.5 with the optimum of pH 7.0, and the appropriate salinity (NaCl) from 0% to 10% with the optimum of 0%. It metabolized many carbohydrates and organic acids and was sensitive to diverse antibiotics including ampicillin and piperacillin. The G + C content of its genomic DNA was 48.2 mol%. The major fatty acids were 2-methyl C15:0 (29.97%), C16: 1omega7c (27.22%), C12:0 (22.22%) and C16: 1omega9c (5.73%).

CONCLUSION

The isolate PY97S was identified as a petroleum hydrocarbon-degrading novel species of genus Marinobacter, holding the potential of being applied in the bioremediation of oil spill.