Screening, Identification and Degradation Characteristics of Petroleum Hydrocarbon Degrading Bacterium Mycolicibacterium Fluoranthenivorans Y3

A highly efficient diesel degrading strain Y3 was screened from the oily sludge of Nanjiang sewage treatment plant of Tianjin port. Through morphological observation, physiological and biochemical test and 16S rRNA gene sequence analysis, it was identified that strain Y3 belonged to Mycolicibacterium sp. Strain Y3 is suitable to grow under medium temperature and acidic environmental conditions, and can still grow normally under the condition of salinity of 3% and Mn²⁺ concentration of 50 mg/L. The strain can tolerate 3%（V/V） diesel oil. After 5 days under the optimum culture conditions, the OD₆₀₀ of the strain reached 2.0 and the degradation rate of diesel oil was 50.1%. The addition of sodium carbonate and sodium acetate can improve the degradation ability of Y3 to diesel oil. Gas chromatography-mass spectrometry（GC-MS） analysis showed that Y3 could degrade all hydrocarbons in diesel oil(C₁₀-C（32）) and had strong degradation ability to linear alkanes. The degradation rate of individual branched alkanes（2,6,10-trimethyltridecane） is 57.6%, which indicates the application potential to repair petroleum hydrocarbon pollution.