摘要
以原料乳为对象,使用脱脂乳平板筛出三株有较强蛋白酶水解性的嗜冷菌,通过时间-酶活曲线复筛出一株高产蛋白酶的嗜冷菌Px-1。针对其产蛋白酶培养基进行了正交优化,研究了其产酶培养基的主要成分,结果表明酵母浸出粉对产酶影响显著。通过本实验最终确定了最佳培养基组成:蔗糖4%,α-乳糖4%,葡萄糖2%;酵母浸出粉0.7%,干酪素0.5%,胰蛋白胨0.3%以及0.05%的吐温80。在此条件下,Px-1产蛋白酶活为42.5451U/mL,高于优化前的测定值30.2291U/mL。
Three psychrotrophic strains coded Px-1 ,Px-3 and Px-5 which could produce protease and have obvious hydrolysis circles on defatted milk powder plate,that were isolated from raw milk. The stains were isolated again by time-enzyme activity curve. The strain Px-1 had the strongest protease activity. Composition of fermentation medium was optimized by quadratic design. The optimum fermentation medium composition was as following.4% sucrose,4% alpha lactose,2% glucose,0.7% yeast extract powder,0.5% casein,0.3% tryptone and 0.05% tween 80. Under the optimum conditions,the protease activity of Px-1 could reach 42.5451U/mL, higher than the value before optimization 30.2291 U/mE
出处
《食品工业科技》
CAS
CSCD
北大核心
2014年第20期204-207,共4页
Science and Technology of Food Industry
基金
国家“十二五”科技支撑计划课题(2012BAD12B08)
国家“973”计划课题(2012CB723706)
关键词
原料乳
嗜冷菌
蛋白酶
培养基
优化
raw milk
psychrotrophic bacteria
protease
fermentation medium
optimization
