Study On Fermentation Conditions Optimized, Purification, Characterization Of Lipase From Bacillus Sp.

Lipases from Bacillus show high thermostability of their lipase activities, stabilities of wide pH range and good organic solvent tolerant, which were applied in biocatalysis nonaqueous media and optically active substance resolution.We studied a new isolated which was conserved by our institute. It was identified as Bacillus sp. by physiological test and biochemical test. A uniform experimental design was used to determine optimum fermentation conditions and medium compositions in shake flask cultivation, optimization data were calculated with DPS software-aid. The optimal lipase-producing conditions of Bacillus sp. were as follows: 0.78% corn starch as best carbon source , 4.0% soy bean meal as best nitrogen source and K2HPO4 0.4%,NaNO3 0.2%, initial pH 10.0,culture temperature was 32C, shark flask capacity was 20ml,stirring rate was 225r/min,germ age was 24h,germ concentration was 10% and fermentation periods was 28h.The lipase was purified to homogeneity using ammonium sulfate precipitation, cation-exchange chromatography (CM-Spephrose FF) and Sephacryl S-200,and its specific activity was improved 9.45-fold.The molecular mass was shown to be 32.08 KDa by SDS-PAGEProperties of the lipase showed1 The optimum temperature was 50C It shows thermostability under 50C2 The optimum pH was 9 0 It showed high activity in a pH range from 7 0 to 11.0.13 There was not increased to enzymatic activity with Ca2+, which indicated lipase from Bacillus sp. was not a Ca2+ -depended lipase.4Nonionic detergent increased enzymatic activity with low concentration, yet it was decreased with high concentration.Inoic detergent showed varied decreased effects to the lipase with either high or low concentrationIt indicated that lipases from Bacillus sp. would be applied widely as it showed high thermostabilities and stabilities of wide pH range...