中性蛋白酶芽孢杆菌BX-4产酶条件及部分酶学性质

Studies on Protease Production Conditions and Enzyme Characterizations of Neutral Protease-Producing Strain Bacillus BX-4

采用稀释平板分离法从土壤中分离到一株产中性蛋白酶芽孢杆菌BX-4.通过单因素碳、氮源以及正交试验确定了最佳产酶培养基配方,同时还研究了起始pH值、金属离子、接种量对产酶的影响以及温度、pH值、金属离子以及表面活性剂对酶稳定性的影响;以最佳培养基为发酵培养基,于37℃、160 r/min振荡培养48 h,酶活达2 519.35 U/mL;该酶最适作用温度为55℃,最适作用pH值为7.5,在pH 7.5缓冲体系中,55℃反应60 min后仍有50%的酶活力.Ca2+和表面活性剂对酶有一定的激活作用,但激活作用不明显.

A strain producing neutral protease was obtained from soil by diluted plated method and was named BX-4. Optimal fermentation medium was obtained through studying carbon resources, nitrogen resources and implementing orthogonal experiment. The effects of initial pH, metal ions and inoculum amount on protease production and the effects of temperature, pH surface-active agent on protease stability were studied. Protease activity reached 2 519.35 U/mL under the conditions of 37℃, 160r/min ,48 h in the optimal fermentation medium. The optimal acting temperature and pH of this enzyme are 55℃ and 7.5 respectively. Protease could maintain half-life at 55℃ incubation for 60 minutes in 7.5 buffer solution; Ca^2＋ and surface active agent could activate protease activity but the effect is not so obvious.