耐有机溶剂蛋白酶产生菌Bacillus cereusWQ9—2发酵条件及酶学性质

以蜡状芽孢杆菌Bacillus cereus WQ9—2为产耐有机溶剂蛋白酶的出发菌株，对其产酶条件进行优化并初步研究了其酶学性质。在单因素实验基础上，通过中心复合实验确定了产酶的最佳发酵条件为酵母粉8g/L，葡萄糖17g/L，KH2P040．5g／L，无水MgS040．3g／L，CaCl20．5g／L，NaCl1．0g/L；pH7．5。实验中发现采用低温发酵能大大缩短菌体产酶周期；通过优化发酵时间由最初84h缩短到48h，最高比酶活为3921U／mL。金属离子螯合剂1，10菲罗啉（1，10-phenanthroline）、乙二胺四乙酸（EDTA）对该酶有较强的抑制作用，表明该酶可能为金属蛋白酶；Ca2＋对该酶的活力及热稳定性有显著提高作用。

Optimum fermentation conditions and enzymatic properties of organic solvent tolerant protease from Bacillus cereus WQ9-2

In order to raise protease production, culture conditions for Bacillus cereus WQ9-2 with the ability to produce organic solvent tolerant protease were optimized by central composite design method. The optimized fermentation conditions were as follows： yeast powder 8 g/L, glucose 17 g/L, KH2PO4 0. 5 g/L, MgSO4 0. 3 g/L, CaC12 0.5 g/L, NaCI 1.0 g/L, and pH 7.5. The cultivation conditions were 25 ~C , and 180 r/rain. Under the optimal conditions for 48 h, the maximum protease production was 3 921 U/mL. The protease activity was activated in the presence of Ca2＋, and inhibited in the presence of EDTA and 1,10-phenanthroline. The results showed that it might be metalloprotease.