Isolation and Biochemical Characterization of Extracellular Lipase Producing Bacterial Strains from Hypersaline and Hyperalkaline Soil

Lipases are exploited as cheap and versatile catalysts to degrade lipids in more modern applications. Fifteen isolates were isolated through enrichment from the hypersaline and hyperalkaline habitats of the state Gujarat. From 15 isolates, nine isolates were selected from primary screening which were showing zone of clearance on tributerene agar medium in presence of 10% NaCl with pH 7.2. Secondary screening was done by estimating lipase activity of the isolates obtained from primary screening in tributyrene broth. Among of the isolates of primary screening, four isolates (LP_A, LP_E, LP_H, LP_O) were selected for further studies which were showing higher lipase activity compared to other isolates. Alkaline lipase production was significant in liquid medium in the alkaline pH range and in higher concentration of salt as well. The characterization of isolates was carried out by biochemical tests followed by the identification of genus of the strain by GIDEON (Global Infectious Diseases and Epidemiology Network). Among the four isolated lipase producers, isolate LP_A, LP_H and LP_O were Gram negative short rod and isolate LP E was Gram positive cocci. Additionally, our biochemical tests showed the occurence of Leptotrichia, Anaerococcus and Pseudomonas spp. Among these spp. Pseudomonas was found to be the more dominant as it showed maximum lipase activity in presence of 10% salt and 4% olive oil. The current study constitutes the first step in the designing process of starter cultures, in order to produce the typical hyperalkaline characteristics of traditionally industrial applicant lipase. However, in the future we can consider genetical characterization and selection of the most desirable strains which can assess their potential as starter cultures for commercial use.