Screening of Lipase Producing Alkalophiles Bacteria and Study of Enzymatic Properties

Objective:To isolate and identify alkalophiles bacteria strain producing lipase and study the properties of lipase.Method: Solid plates with soybean oil as sole carbon source were employed to isolate lipase producing strain.Analysis of 16S rDNA gene sequence and physiological and biochemical experiments were employed to identify the strains.Culture conditions for the production of lipase were optimized with single factor experiments and its properties were also investigated.Result: An alkalophiles bacteria strain producing lipase was isolated,and was indentified as Pseudomonas sp,called as Pseudomonas sp.C-36.Maximum lipase yield was 2.782 IU/ml under the optimum culture condition,which is glycerol 2%(W/V),peptone 0.7%(W/V),yeast extract 0.5%(W/V),K2HPO4 0.2%(W/V),MgSO4·7H2O 0.5(W/V),NaCl 0.3%(W/V),Triton X-100 0.01%(W/V),pH 9.5,37℃,180 r/min and 24h incubation.The optimal temperature and pH of the lipase were 40℃ and 9.0,respectively.Half-time of the lipase at 50℃ was 2h.Ca2+ greatly increased the activity of lipase,whereas Zn2+ inhibited the activity of lipase from Pseudomonas sp.C-36.It was found the lipase from Pseudomonas sp.C-36 was resistant to organic solvents.Conclusion:An alkalophiles lipase producing strain,identified as Pseudomonas was isolated and it maybe useful for industry in the future.