家蚕肠道产蛋白酶菌的筛选及其培养条件研究

Study on Screening and Cultivation Condition of the Protease Producing Bacteria from Gut of Silkworm (Bombyx mori)

为了获得产蛋白酶能力高的菌株,采用透明圈法从家蚕肠道中分离筛选得到21株产蛋白酶的菌株.通过比较透明圈大小和测定发酵液酶活力,筛选出一株产酶能力较高的菌株P6-3.利用16S rRNA序列分析鉴定其种属,并研究最适发酵条件.镜检和测序结果表明该菌为葡萄球菌属细菌,最佳产酶条件:葡萄糖35 g/L、酵母浸出粉20 g/L、磷酸二氢钾1.5 g/L、硫酸镁0.5 g/L、温度40℃、起始pH 9.0、装瓶量60 mL/250 mL、165 r/min振荡培养48 h,此时P6-3菌株最大产酶量可达93.212 U/mL.

To obtain strains with high protease production capacity,21 protease producing strains are isolated and screened from the intestinal tract of silkworm by transparent circle method.By comparing the sizes of the transparent circles and measuring the enzyme activity of the fermentation broth,a strain P6-3 with high enzyme producing ability is obtained.The species are identified by 16 S rRNA sequence analysis,and the optimum fermentation conditions are studied.The bacteria are staphylococcus bacteria and the best conditions for enzyme production are:35 g/L glucose powder,yeast leaching 20 g/L,potassium dihydrogen phosphate 1.5 g/L,magnesium sulfate,0.5 g/L,temperature 40℃,starting pH 9.0,60 mL/250 mL bottle,and shaking at 165 r/min for 48 h.Under such conditions,the measure of the enzyme production strain P6-3 can reach 93.212 U/mL.