酶解稀奶油使牛奶增香的脂肪酶产生菌的筛选及产酶条件优化

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

该文从天然干酪等可食用样品中,筛选得到10株脂肪酶高产菌株,其中菌株PM-1产酶活力高且酶解稀奶油产物用于脱脂乳增香的效果最好,该菌经鉴定为假单胞菌。通过正交试验对PM-1的产酶培养基及产酶条件进行优化,其最适产酶培养基为可溶性淀粉1.5g/L,乳脂肪乳化液15g/L,牛肉膏8g/L,硫酸铵1g/L,NaCl 2.0g/L,K2HPO40.5g/L,MgSO40.5g/L,KH2PO41.0g/L;最适产酶条件为培养基初始pH值为6.8,25℃,摇床培养72h。以此获得的发酵液酶活力为4.70U/mL。

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-lwere investigated through orthogonal test. The optimal medium contained soluble starch 1.5g/L, milk fat emulsion 15g/L, beef extract 8g/L, （NH4）2SO4 lg/L, NaCI 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.