Isolation and identification of a Bacillus subtilis and its characterization in degrading heavy oil

Heavy oil was used as the sole carbon source to isolate and screen for bacteria degrading petroleum hydrocarbon from the heavy oil polluted soil.The strain CZ-1 was isolated and identified as Bacillus subtilis by physiological and biochemical identification and analysis of 16S rDNA.Shaking culture experiment results show that the best degradation conditions of the strain CZ-1 were pH 7.5~8.5,35~45 ℃,and the mineralized rate 8 ~16 g/L.When the heavy oil density is 0.1 g/L,the degrading rate of heavy oil is up to 34.3% in the optimal conditions.GC-FID analysis indicates that in the saturate hydrocarbons,n-alkane could be degraded significantly;GC-MS analysis indicates that in the aromatic hydrocarbons,naphthalene and alkyl naphthalene almost disappeared after degradation,dibenzothiophene were degraded significantly by the strain CZ-1,while phenanthrene and alkyl phenanthrene increased.