酱香型大曲中蛋白酶产生菌的分离鉴定及产酶条件研究

对酱香型大曲中蛋白酶产生菌进行分离鉴定,并对其最适产酶条件进行研究.采用酪素培养基,从大曲中分离出3株蛋白酶产生菌,筛选出酶活力最高的菌株,经16S rRNA同源序列分析并结合其形态学特征鉴定为枯草孢杆菌(Bacillus Subfilis).以小麦为固体培养基,从温度、初始pH值、培养基水分含量、环境湿度等方面研究其最适发酵条件.最终结果为在培养温度为45℃、初始pH值为5.0、培养基内水分的含量为55％、环境湿度为80％条件下培养72h,其酶活力可达1717.5U/g.

Isolation, identification and enzyme production conditions ofproteinase-producing s~ains from sauce-flavor Daclu

The protease-producing strains were isolated from sauce-flavor Daqu. The optimal production conditions of protease were also studied. On casein medium, three protease-producing strains were isolated, one of which had highest protease-producing activity and was identified as Bacillus subtilis by 16S rRNA gene sequencing and morphological characteristics. Using wheat as solid culture medium, the fermentation conditions including fermentation temperature, initial pH, moisture content of culture medium and environment humidity were optimized. The results showed that the pro-tease activity could reach 1717.5U/g when the fermentation was conducted at 45℃ for 72h with initial pH value of 5.0, the moisture content of culture medium was 55% and the environmental humidity was 80%.