Isolation and identification of a high-efficient diesel degrading bacterial strain Acinetobacter sp. L7
HU Chun-hui1,2, YU Hao2, ZHAO Yang-guo1, TIAN Wei-jun1, BAI Jie1
1. Key laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China;
2. College of Life Science, Qingdao Agricultural University, Qingdao 266109, China
A high-efficient diesel degrading bacterial strain isolated from oil-contaminated soil in Liaohe oil field was identified as Acinetobacter sp. and named as L7. The strain could efficiently grow with diesel, n-tridecane, n-hexadecane, n-heptadecane, n-octadecane and n-nonadecane as its sole carbon and energy source. The cultivation conditions of the strain L7 in diesel basic salt medium were investigated. The suitable pH value for the growth of the strain ranged from 6.0~9.0 with the optimum value of 7.0. The optimum temperature and salinity for the cultivation of the strain was 30℃ and 1%, respectively. The degradation efficiency of diesel oil was 61.5% under the optimum conditions. Based on the whole-genome DNA sequence analysis of the bacterial strain, an alkane hydroxylase gene, alkB, was identified. To study the function of the alkB gene in n-alkane utilization by the bacterial strain, the pME6032-alkB plasmid was constructed and electroporated into another bacterial strain Pseudomonas KT2440, which could not grow in diesel. The electroporated bacteria Pseudomonas KT2440 could grow in diesel basic salt medium. Through gas chromatography-mass spectrometric analysis, the degradation capacity of the bacterial strain L7 for n-alkanes and the roles of the alkB gene were determined. The results indicated that the n-alkanes were degraded by the strain L7 via the terminal oxidation and β-oxidation pathway.
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