Screening of bacterial strains for lipase production and its application in biodiesel synthesis

Abstract

The qualitative screening of 46 bacterial isolates/strains for lipase production was carried out using Rhodamine olive oil agar assay. On this basis, four bacterial strains, viz. Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Pseudomonas fluorescens and Bacillus aryabhattai were identified to be positive for lipase production. The lipase activity index (LAI) of the selected bacterial strains ranged from 1.57 to 2.90 with highest LAI observed for P. aeruginosa (2.90). P.aeruginosa exhibited significantly high lipase activity of 726.35, 505.33 and 355.98 pkat ml-1 in olive, karanj and jatropha oil liquid cultures, respectively. Among four bacterial strains, P. aeruginosa possessed significantly high lipase activity in all three oil liquid cultures. Olive oil served as most suitable carbon source for production of bacterial lipases followed by karanj and jatropha oil. The conversion of olive, karanj, jatropha and soybean oil into biodiesel (methyl ester) by using P. aeruginosa lipase as biocatalyst was 64.2, 59.7, 57.4 and 57.9 per cent, respectively.