产中性蛋白酶种曲培养基的优化及酶学特性研究

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

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。

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.