产蛋白酶菌株Bacillus subtilis GS-1发酵条件优化及蛋白酶水解应用初步研究

 利用Plackett-Burman (PB)试验和相应面优化方法对枯草杆菌GS-1菌株发酵产蛋白酶的条件进行优化，以期获得高活性的蛋白酶发酵液。同时，将发酵所产蛋白酶用于蛋白水解实验，以进一步考察蛋白酶的水解特性。首先，通过PB试验，筛选出3个影响菌株发酵过程中蛋白酶活力的主要因子(氯化铵、初始pH值及培养温度)。其次，通过响应面优化法，进一步探讨各参数之间的相互关系并最终拟合得出发酵产酶活的方程。结果表明，在氯化铵 (3.768 g/L), 初始pH (5.6) 以及培养温度 22.4 ℃的条件下，发酵液中蛋白酶的最高酶活力能达到372.814 U/mL。水解试验结果表明：相对于植物来源的蛋白，该蛋白酶粗提物对于动物来源的蛋白具有较大的水解偏好型。该蛋白酶粗提物对于由谷氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸或精氨酸所组成的化学键有较强的水解偏好性。以上结果表明：该菌株发酵所产的蛋白酶在蛋白水解加工行业中具有潜在的开发应用价值。

Optimization of Protease Activity from Bacillus subtilis GS-1 and Potential Applications in Protein Hydrolysis

This study was conducted to optimize conditions for crude proteases activity from Bacillus subtilis GS-1 by Plackett-Burman(PB) design and response surface methodology.Meanwhile,potential applications of proteases in protein hydrolysis were also determined.Three significant variables(NH4Cl,initial pH value and cultural temperature) necessary for the enhancement of proteases activity were selected by using PB design.Furthermore,an empirical model was developed to describe the relationships between these tested variables.Maximum enzymatic activity was attained at 372.814 U/mL,with NH4Cl at 3.768 g/L,pH at 5.6 and temperature at 22.4 ℃.Results of hydrolysis experiments indicated that the protease more prefer to hydrolysis proteins from animal source than that from plant source.The protease was prone to hydrolyze chemical bond that composed by amino acids of Glu,Val,Ile,Leu,Phe or Arg,and had great potential for applications in protein hydrolysis.