地衣芽孢杆菌2709高去酰胺活性碱性蛋白酶发酵条件及酶学性质的研究

Study on fermentation conditions and enzymatic properties of alkaline protease with high deamidation activity from B. licheniformis 2709

就地衣芽孢杆菌2709发酵生产高去酰胺活性碱性蛋白酶的发酵条件进行了研究,以酶液对大豆蛋白的去酰胺度和肽键水解度为指标,对产酶条件进行优化,并研究了该酶的基本酶学特性;确定了培养基的最佳碳源为玉米粉,最佳氮源为黄豆饼粉,C/N在1:2～1:1范围时去酰胺度最高;最适摇瓶发酵条件为:种龄18h,接种量2%,装液量30mL/100mL,摇床转速140r/min,pH7.0,35℃,发酵50h;碱性蛋白酶最适作用pH为10.0,最适反应温度为50℃,60℃保温2h后仅存5.9%的活力,在pH8～11之间有较高的pH稳定性。

The fermentation conditions of alkaline protease with high deamidation activity by B. licheniformis 2709 were studied. Using the degree of deamidation and amide hydrolysis of soybean by the alkaline protease as indicators, the condition of enzyme production was optimized, and the basic enzyme properties of the alkaline protease were also studied. It was determined that the optimal carbon source and nitrogen source was corn meal and soybean meal powder, respectively, the maximum degree of deamidation could be obtained when the ratio of carbon to nitrogen at the range of 1：2 to 1：1.The optimal fermentation conditions were as follows： culture age 18h, inoculation 2%, medium volume 30mL/100mL, rotation speed 140r/min, pH %0, 35℃, fermentation time 50h. The optimal conditions of alkaline protease were as follows： pH 10.0, 50℃. After incubation at 60℃ for 2h, the residual activity of the enzyme was only 5.9%, and the enzyme was relatively stable at pH 8- 11.