一株产蛋白酶不动杆菌的分离与酶学性质

Screening of a Protease-Producing Strain Acinetobacter calcoaceticus and Characterization of the Enzyme

DOI：10.3969/j.issn.1673-1689.2017.01.002

中文关键词: 蛋白酶 筛选 鉴定 醋酸钙不动杆菌 酶学性质

英文关键词: protease,screening,identification,Acinetobacter calcoaceticus,enzymatic properties

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中文摘要:

以脱脂奶粉或羊毛粉为唯一碳氮源，从环境样品中筛选蛋白酶产生菌，首次获得一株高产蛋白酶的醋酸钙不动杆菌（Acinetobacter calcoaceticus） E9，初步发酵优化显示，该菌株的最适发酵产酶温度35 ℃，培养基初始pH 6.0，接种量为质量分数4%，培养时间30 h；发酵培养基：蔗糖10 g/L，牛肉膏15 g/L，K2HPO4·3H2O 7 g/L，KH2PO4 3 g/L，MgCl2·6H2O 1 g/L。酶学性质初步研究表明，不动杆菌E9所产的蛋白酶属于中性蛋白酶，最适作用温度50 ℃，最适pH 8.0，在pH 5.0~8.0及40 ℃以下时具有良好的稳定性，酶反应动力学参数Km为7.067 mg/mL，Vmax为966.7 μg/（mL·min）。

英文摘要:

A strain E9 to produce protease efficiently was screened from environmental samples with skimmed milk as carbon and nitrogen sources and was identified to be a strain of Acinetobacter calcoaceticus based on biochemical and physiological properties as well as the 16S rDNA gene sequencing. Its optimal fermentation conditions were found to be temperature 35 ℃，initial pH 6.0，inoculation 4% and culture time of 30 h，and the optimal fermentation medium contained 10 g/L of sucrose，15 g/L of beef extract，7 g/L of K2HPO4·3H2O，3 g/L of KH2PO4 and 1 g/L of MgCl2·6H2O. The resulting protease showed high activity and superior stability with moderate temperature and neutral pH values，and its kinetic parameters Km and Vmax were determined to be 7.067 mg/mL and 966.7 μg/（mL·min），respectively.

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