产中性蛋白酶种曲培养基的优化及酶学特性研究

以中性蛋白酶活力为检验指标，采用响应面法对米曲霉产中性蛋白酶的种曲培养基进行优化，确定其最佳配方组成为：面粉用量2．24g，花生粕用量8．46g，氯化钙用量0．028g，种曲中性蛋白酶活力高达15559．40U／g。经研究纯化后中性蛋白酶酶学特性，发现中性蛋白酶的最适pH为7．0，在pH5．0-7．0范围内具有良好的稳定性；最适作用温度为50℃，在40-55℃条件下能保持较高的酶活力；试验金属离子对蛋白酶没有显著的激活作用，Ba^2＋、Fe^2＋、Zn^2＋和Cu^2＋具有显著的抑制作用。

Optimization of the Medium for Production of Neutral Protease and Research of the Enzymatic Properties

Response surface analysis was applied to optimize the medium for production of neutral protease. The result showed that the optimum medium formula compositions were flour 2.24 g, peanut meal 8.46 g and calcium chloride 0.028 g, under which the neutral protease activity was up to 15559.40 U/g. The optimum pH and temperature for neutral protease were 7.0 and 50 ℃, respectively. The protease was stable at pH 5.0-7.0 and at 40-55℃C. The tested metal ions did not significantly activate the protease, while the ions Ba^2＋, Fe^2＋, Zn^2＋ and Cu^2＋ strongly inhabited its activity.