【摘要】 为了选育高活力碱性蛋白酶产生菌株。采用复合诱变(紫外照射、NTG、离子注入)方法,结合平板初筛与摇瓶复筛。获得一株高产突变株HAPN-169,其酶活力为3.5×10u/mL。高产菌株HAPN-169根据气液接触中体积传氧系数kLa相同的原则发酵放大(7L,30L,200L),其发酵参数为:温度34℃,装液系数0.7,接种量5%,使溶氧维持在20～30%,控制发酵过程pH不低于7.0。在7L发酵罐,发酵时间为54小时,酶活力为3.6×104u/mL;在30L发酵罐,发酵时间为50小时,酶活力为3.86×104u/mL;在200L发酵罐,发酵时间为36小时,酶活力为4.2×104u/mL。发酵液pH在7.5左右时,酶活力在峰值,发酵终点一到,必须马上下罐。该结果对为我国碱性蛋白酶工业发展提供一定的基础。更多还原

【Abstract】 In order to screen high-yield alkaline protease producing strain,the complex mutation(UV radiation,NTG,and N+ ion implantation) was applied and the plate screen and shake flask screen were carried out in the study. The high-yield protease strain HAPN-169 was obtained with its protease activity as 3.5×104 u/mL. The experiment was then scaled up into 7L,30L and 200L fermentors on the basis of same kLa. The optimum fermentation conditions were obtained as:1) the optimal culture condition is 34oC;2) the fermentation medium volume is 0.7;3) inoculation is 5%;4) dissolved oxygen is approximately 20～30%;and 5) the pH value is over 7.0 during the controlled fermentation process. In a 7L fermentor,the alkaline protease activity was about 3.6×104 u/mL after cultivating for 54 hours. In a 30L fermentor,the protease activity was about 3.86×104 u/mL after cultivating 50 hours. In a 200L fermentor,the protease activity was about 4.2×104u/mL after cultivating 36 hours. When the pH-value of the culture was around 7.5,the activity of alkaline protease was close to tip,and the fermentation must be stopped. The study laid a solid basis for the development of alkaline protease industry.更多还原