浓香型大曲中优势蛋白酶产生细菌的分离及产酶条件研究

对浓香型大曲中蛋白酶产生细菌进行分离,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5株产蛋白酶菌株,筛选出酶活力最高的菌株,其酶活为53.40 U/mL。以小麦为固体培养基,从pH值、培养基水分含量、碳源添加量、氮源添加量、接种量、培养温度和培养时间等方面研究此菌株的最适产酶条件。结果表明,在水分含量65%、初始pH6.0、蔗糖添加量6%、硫酸铵添加量1%、接种量12%、温度40℃,培养时间5 d的条件下,其酶活可达262.18 U/mL,为菌种复筛时的4.91倍。

Isolation of Protease-producing Bacteria Strains from Luzhou-flavor Daqu and Study on Its Protease-producing Conditions

Protease-producing Bacillus strains were isolated from Luzhou-flavor Daqu and its optimum protease-producing conditions were investigated.5 protease-producing Bacillus strains were isolated from Daqu by use of casein agar culture mediums and the strain with the highest protease activity(53.40 U/mL) was screened out.Then wheat was used as solid culture medium to investigate the optimum protease-producing conditions and the optimum conditions were summed up as follows: moisture content was 65 %,initial pH value was 6.0,sugar addition level was 6 %,ammonium sulfate addition level was 1 %,yeast inoculating quantity was 12 %,culture temperature was at 40 ℃,and culture time was 5 d.Under the above conditions,the produced protease activity could reach up to 262.18 U/mL,4.91 times of that before secondary screening.