Screening of lipase-producing bacteria for enzymatic hydrolysis of cream to enhance milk flavor and optimization of lipase production conditions

Ten lipase-producing bacteria were isolated from cheese,cream and butter.One strain named PM-1 had high lipase-producing ability.The lipase from PM-1 showed best performance for flavor enhancement of milk by hydrolyzing cream.PM-1 was identified as Pseudomonas sp..The optimal culture conditions for lipase production of PM-1were investigated through orthogonal test.The optimal medium contained soluble starch 1.5g/L,milk fat emulsion 15g/L,beef extract 8g/L,(NH4)2SO4 1g/L,NaCl 2.0g/L,K2HPO4 0.5g/L,MgSO4 0.5g/L and KH2PO4 1.0g/L.The culture was kept in shaking incubator at 25?? for 72h with a initial medium pH of 6.8.The lipase activity of the broth reached 4.70U/ml.