Yang_2007_J.Mol.Catal.B.Enzym_45_91

A lipase gene lipA and its chaperone gene lipB were cloned from Burkholderia cepacia strain G63. The lipA was composed of 1092bp, encoding 363 amino acid residues, and the lipB composed of 1035bp, corresponding to 344 amino acid residues. The significant amino acid similarity with Pseudomonas cepacia lipase revealed that this enzyme could be classified into the lipolytic subfamily I.2. The lipA and lipB genes were cloned into pBBR1Tp vector and conjugated into B. cepacia strains G63 with the help of pRK2013. The recombinant strain was fermented in 10l bioreactor and the lipase was purified by a combination of ammonium sulfate fractionation, DEAE ion-exchange chromatography and gel filtration. The purified lipase kept stable at a temperature range of 4070C. After incubated at 70C, the optimal temperature of this enzyme, for 10h it remained 86.1% of its activity. The enzyme was also highly tolerant to a series of organic solution. Incubated in 50% methanol solution up to 48h, the enzyme still kept 98.3% of its activity. The transesterification activity of soybean oil to fatty acid methyl esters (FAMEs) reached 87.8% after 72h, indicating that it is a potential biocatalyzer for biodiesel production.