Characterization and Cultural Optimization of Lipase Producing Bacteria Isolated from Oil Contaminated Soil

Kyaw Swa Lynn, Tin Tin Hla

Abstract: The present study involves isolation and characterization of lipase producing bacteria from oil-contaminated soils and comparative studies of their lipase activities by two quantitative methods titrimetric and spectrophotometric assay methods. Totally, 17 bacterial lipolytic strains were screened on tributyrin agar medium. Five isolates which possessed higher lipase activity were further confirmed by Rhodamine B-olive agar for true lipase activity. After quantitative studies in fatty acid formations, the isolate 8a was selected as the best lipase producer strain. Morphological, biochemical characteristics and 16s rRNA sequence analysis had been carried out. Potent isolate was identified as Bacillus subtilis. Growth conditions of Bacillus subtilis for maximum lipase productivity were optimized. The optimum temperature and pH for lipase productivity were 38C and pH 6 at 5 days incubation time. The optimum condition for enzyme productivity was obtained when 2 % olive oil substrate was used, and olive oil was found as the best substrate for lipase synthesis.

Keywords: lipase producing bacteria, Rhodamine B-olive oil agar, tributyrin agar, characterization, sequence analysis, optimization