产碱性蛋白酶嗜碱芽孢杆菌的筛选及其研究

利用造纸黑液对土样进行富集,筛选出3株碱性蛋白酶酶活力较高的嗜碱芽孢杆菌X1、X2、X3。对它们的生长曲线,产酶曲线,在不同C、N源、pH值、盐浓度下的产酶活力进行的研究表明:3株嗜碱芽孢杆菌(Bacillussp.JBX1、X2、X5)酶活力较高(达到100U/mL),X2最高酶活可达140U/mL。最适pH值为9.5,碳源中的蔗糖,氮源中的酵母浸提物和硝酸钠均利于产酶。X1、X5两株嗜碱芽孢杆菌均表现出较强的耐盐耐高渗透压的能力。X1在11%的NaCl浓度下生长良好,酶活仍然达到80U/mL以上。而X2和X5对温度的耐受性比较强,在经70℃处理15min后依然保持了80%以上的酶活力,所产蛋白酶为高温碱性蛋白酶,从而为进一步的应用和研究奠定了基础。

Screening of Alkaline Protease Producing Alkalophilic Bacillus sp.

Three alkaline protease producing Bacillus strains JB-X1, X2, and X5 were isolated from earth samples enriched through black wastewater of papermaking. Their growth curves, enzyme producing curves, and their enzyme-producing activity under different carbon, nitrogen sources, pH values, and salinities were studied. The results indicated that enzyme activity of the three alkalophilic Bacillus strains JB-X1, X2, and X3 were high (up to 100 {U/mL}), and X2 was the highest, it hit up to 140 U/mL. The optimum pH value was 9.5, cane sugar of carbon source, yeast extract of nitrogen source, and sodium nitrate were conducive to enzyme production. Two alkalophilic Bacillus strains X1 and X5 performed stronger resistant capabilities of salt and high osmotic pressure. X1 grew well in 11% of NaCl, and enzyme activity still remained at 80 U/mL, and the protease it produced was alkaline protease of high temperature, thus laid the foundation of further study on their applications.