溶剂稳定性蛋白酶产生菌Bacillus licheniformis YP1的发酵优化

Optimization of cultivation conditions of Bacillus licheniformis YP1 for producing organic solvent-stable protease

溶剂稳定性蛋白酶产生菌Bacillus licheniformisYP1分离自油田土样。考察了碳源、氮源、金属离子等营养因素对YP1菌株发酵产溶剂稳定性蛋白酶的影响。YP1菌株发酵产胞外蛋白酶的最佳碳源为淀粉,果糖、甘露糖和乳糖显著抑制产酶;最佳氮源为酵母膏,干酪素、酵母粉和牛肉膏促进产酶,玉米浆和尿素显著抑制产酶。Mn2+可以显著促进酶活,Mg2+可以促进产酶,在初步优化的培养条件下,YP1菌株的胞外蛋白酶产量达980 U。

An organic solvent-tolerant bacterium producing an organic solvent-stable protease was isolated from soil and identified as Bacillus licheniformis YP1. The effects of carbon source, nitrogen source and metal ions on the production of organic solvent-stable protease by strain YP1 were investigated. The best carbon source was starch. Fructose, sorbitol, and lactose greatly reduced the protease production. The best organic nitrogen source was yeast extract paste. Casein, yeast extract powder, and beef extract paste supported protease production while corn steep liquor inhibited the protease production. The addition of metal ions Mg^2＋ increased the protease production, while Mn^2＋ enhanced the protease activity. The specific protease activity was up to 980 U when strain YP1 was cultivated in the optimized media.