Screening of a Hydrocarbon-degrading Bacterial Group and Study on Its Degrading Conditions

5 highly efficient hydrocarbon-degrading mixed bacteria were,obtained from petroleum-contaminated samples of Karamay,Xinjiang by the traditional method of enrichment and isolation,and it was found that KL9-1 group has a wide temperature tolerance range and higher hydrocarbon degrading ability.The degradation rate of thin oil and heavy oil was up to 43.27%and 20.09%respectively through 7d at 45℃.The environmental factors on the degradation of petroleum hydrocarbon effect of KL9-1 group were studied using single factor test.Experimental results indicated that the inoculums amount of KL9-1,initial concentration of petroleum hydrocarbons,initial pH value,shaking speed and adding amount of surfactant can affect the degradation efficiency of petroleum hydrocarbon.The degradation rate of thin oil and heavy oil was up to 62.49%and 40.36%respectively at 35℃under the conditions of inoculums amount 6.0%,initial concentration of petroleum hydrocarbons 1.5%,initial pH value 7.5,rotation speed 120r/min and adding 200 mg/kg Tween80.