重组锰超氧化物歧化酶工程菌摇瓶发酵条件的优化

通过单因素试验对重组锰超氧化物歧化酶(Recombinant Manganese Superoxide Dismutase,rMn-SOD)工程菌的摇瓶发酵的培养基(碳源、氮源、无机盐)和培养条件(接种量、乳糖浓度、时间、温度、摇床转速、pH值等)进行了初步优化.结果表明,工程菌发酵的优化培养基组分(质量分数)为:1.5%蛋白胨、1.5%酵母提取物、1.0%NaCl、0.4%KH2PO4、0.8%K2HPO4、1.5%(体积分数)甘油、0.2%NH4Cl和5 mmol/L MnCl2.乳糖诱导表达的优化条件为:以5%接种量培养5 h后,加入质量分数为0.25%的乳糖进行诱导表达6 h.当发酵温度为37℃、摇床转速为180 r/min、培养基的初始pH值为7.0时,表达的rMn-SOD的酶活力高.在优化条件下,工程菌的SOD活性达1 969.9 U/mL,比活力达1 081.8 U/mg.

Optimization of Fermentation Conditions in a Shaker for the Recombinant Manganese Superoxide Dismutase from Engineering E.coli

Fermentation media(carbon source,nitrogen source,inorganic salt)and cultivation conditions(inoculum quantity,lactose concentration,time,temperature,shaker speed,pH value etc.) by single factor researches were preliminarily optimized in a shaker for the recombinant manganese superoxide dismutase from engineering E.coli.The results showed that the optimized culture media for the engineering E.coli were 1.5 % trytone,1.5 % yeast extract,1.0 % NaCl,0.4 % KH2PO4,0.8 % K2HPO4,1.5 % glycerine,0.2 % NH4Cl and 5 mmol/L MnCl2.The optimized lactose induction conditions were growth for 5 h after inoculation at 5 % inoculum quantity,and then adding 0.25 % lactose to induce for 6 h.The enzyme specific activity was the highest when the fermentation temperature was 37 ℃,the shaker speed was 180 r/min,and the original medium pH value was 7.0.Under all of these optimized conditions,SOD from the engineering E.coli exhibited the enzymatic activity of 1 969.9 U/mL and the specific activity of 1 081.8 U/mg.