Isolation, Identification and Degradation Characteristics of Oil Degrading Bacterial Strain

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℃, initial pH 7.3, oil concentration 0.6%, salt concentration 0.5%, inoculum amount 8%, the optimal N and P was (NH4)2SO4 and K2HPO4. Conclusion: This study provides microbial resources for bioremediation of petroleum contaminated soil.