Characterization of Lipase from Bacillus subtilisI-4 and Its Potential Use in Oil Contaminated Wastewater

ABSTRACTA lipase producing bacterium was isolated from oil contaminated effluents of various industries from Sheikhupura Road, Pakistan, and, on the basis of biochemical and 16S rRNA ribotyping, was identified asBacillus subtilis. The optimum temperature and pH for the growth of the culture were 37ºC and 7.0, respectively.B. subtilis I-4 had a lag phase of 4 h in LB medium while this phase prolonged to 6 h in oil containing medium. The optimum temperature and pH for the enzyme activity were 50ºC and 7.0, respectively. Maximum lipase activity was found in the presence of Ca ions. Olive oil and Tween 80 induced lipase gene in the bacterium while concentration of oil greater than 2% retarded the growth of the organism. In addition to lipaseB. subtilis I-4 also produced alkane hydroxylase and biosurfactant which could make this bacterium potential candidate for lipase production as well as bioremediation of oil-contaminated wastewater.

GPo1 alkB gene expression for improvement of the degradation of diesel oil by a bacterial consortium

To facilitate the biodegradation of diesel oil, an oil biodegradation bacterial consortium was constructed. The alkane hydroxylase (alkB) gene of Pseudomonas putida GPo1 was constructed in a pCom8 expression vector, and the pCom8-GPo1 alkB plasmid was transformed into Escherichia coli DH5α. The AlkB protein was expressed by diesel oil induction and detected through SDS-polyacrylamide gel electrophoresis. The culture of the recombinant (pCom8-GPo1 alkB/E. coli DH5α) with the oil biodegradation bacterial consortium increased the degradation ratio of diesel oil at 24 h from 31% to 50%, and the facilitation rates were increased as the proportion of pCom8-GPo1 alkB/E. coli DH5α to the consortium increased. The results suggested that the expression of the GPo1 gene in E. coli DH5α could enhance the function of diesel oil degradation by the bacterial consortium.