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Objective: The aim of study is to obtain a strain which can effectively degrade oil. Methods: By enrichment, domestication and separation of culture from the sample which comes from Qianjiang Guanghua Oilfield, the pure culture (G-40) was selected from the medium supplemented with oil as the sole source of carbon. The G-40 was preliminarily identified and classified by morphological observation, physiological and biochemical determination and sequence analyses of 16S rDNA. Effects of temperature, pH, oil concentration, salt concentration, inoculation amount, N and P source on the degradation of the oil were studied by single factor test. Meanwhile, the effects of temperature, pH, oil concentration and salt concentration were optimized by orthogonal design. Result: G-40 was isolated and identified as Brevibacillus laterosporus. The orthogonal design showed that the degradation rate of oil could reach 20.81%, 24.34% and 31.15% at 10 d, 20 d and 40 d under the optimal conditions which was 35˚C, initial pH 7.3, oil concentration 0.6%, salt concentration 0.5%, inoculum amount 8%, the optimal N and P was (NH 4 ) 2 SO 4 and K 2 HPO 4 . Conclusion: This study provides microbial resources for bioremediation of petroleum contaminated soil.

Objective: In order to study the microbial remediation of oil contaminated soil. Methods: The method of soil composting was adopted. G-40, G-94 and G-40 + G-94 were added into the soil with 2% oil, adding 20% bran and adding distilled water to keep the soil water content in 35%, and it was incubated at 35˚C. After sampled, the alkali hydrolysable nitrogen, available phosphorus and oil content were measured. Result: The oil removal rates of G-40, G-94 and G-40 + G-94 treatment groups were 29.08%, 31.09% and 32.68% on 100 th day, respectively. Conclusion: This study provides a reference for microbial remediation of petroleum contaminated soil.

Objective: In order to study low activity of petroleum-degrading strains. Methods: We added oil degrading strains to compost, the compost is made of soybean meal, corn flour, bran and sawdust, in the last, we added the oil degrading strains-compost contaminated soil. Result: The oil removal rates were determinated by gravimetric method. The oil removal rates of control group, oil contaminated soil + compost group and oil contaminated soil + oil degrading strains-compost group were 23.4%, 31.6% and 49.7% on 60 th day, respectively. Compared with the control group, the oil removal rate of oil contaminated soil + oil degrading strains-compost group increased by 26.3%. Conclusion: The research indicates that oil contaminated soil + oil degrading strains-compost can improve petroleum-degrading rates.

The aim of this study is to construct petroleum degrading agent (PDA) which can effectively degrade oil. By enrichment, domestication, and separation of culture from the soil sample of Qianjiang Guanghua Oilfield, the pure culture of three petroleum degrading bacteria G-40, G-53, and G-94 was identified from the medium supplemented with oil, which served as the sole source of carbon. The species of G-40 and G-53 were preliminarily identified and classified by morphological observation, physiological and biochemical determination, and sequence analyses of 16S rDNA. The species of G-94 was preliminarily identified and classified by morphological observation, physiological and biochemical determination, and sequence analyses of ITS rDNA. The optimal inoculation proportion of these three bacteria strains and bran proportion in composition of PDA were determined through orthogonal test. G-40, G-53, and G-94 were isolated and identified as Brevibacillus laterosporus, Tsukamurella inchonensis, and Candida tropicalis, respectively.