以传统的菌种选育方法,从7个土壤样品中筛选到1株产角蛋白酶活性较高的菌株金色链霉菌(Streptomyces aureus)K13,该菌株所产角蛋白酶为中温碱性角蛋白酶,最适温度为55℃,最适p H为8.5,分子质量约为46 k Da;该菌株产酶属于生长偶联型,摇瓶发酵周期为64 h;以羊毛角蛋白为底物发酵产角蛋白酶时添加合适的碳源(葡萄糖)或氮源(蛋白胨或Na NO3)对产酶有明显的促进作用;通过4因素3水平的正交实验设计,在最佳发酵培养基下,该菌株产酶活力达到44.2 U/m L,较优化前提高了10.3倍。

A keratinase-producing strain was obtained from seven soil samples through traditional methods and identified as Streptomyces aureus K13. The K13 keratinase was proven to be a middle-temperature-alkaline enzyme with optimum temperature of 55℃ and optimum p H of 8. 5. Its molecular weight was about 46 k Da. The keratinase production was highly associated with cell growth. Its fermentation period was 64 h. Using appropriate carbon source( glucose) or nitrogen source( peptone and Na NO3) will promote keratinase production in the fermentation. By four factors and three levels orthogonal design,44. 2 U / m L keratinase was obtained under optimal fermentation conditions,which was 10. 3 times higher than the initial level.