亚硝酸还原酶高产菌株的筛选及发酵条件优化

Screening of High Nitrite Reductase Producing Strains and the Optimization of Fermentation

通过紫外线对巨大芽孢杆菌MPF-906进行了诱变处理,提高了产酶能力,变异株Z85酶活达到28.76U/mL。进一步对其发酵条件进行研究,优化了培养基和培养条件。优化的培养基为:葡萄糖1.5%,牛肉膏0.2%,硫酸铵0.1%,K2HPO40.135%,KH2PO40.07%,NaCl 0.1%;无机盐溶液10 mL/L(即MgSO.47H2O0.04%、MnSO.4H2O 0.001%、CaCl.22H2O 0.002%)。发酵条件为:摇床转速160 rpm,接种量4%,初始pH6.5,30℃发酵20 h。在此最优化条件下,亚硝酸还原酶的酶活达到45.94 U/mL。

The nitrite reductase production strain B. rnegaterium MPF-906 was treated with UV. The high nitrite reduetase producing mutant Z85 was obtained and its nitrite reductase activity was 28.76 U/mL. The effects of compositions of culture medium and cultural conditions on nitrite reductase production were investigated. The optimal culture media are： glucose 1.5%, beef extract 0. 2%, （NH4 ）2SO4 0.1%, K2HPO4 0. 135%, KH2PO4 0.07%, NaCl 0.1% , MgSO4.7H20 0.04% , MnSO4.H2O 0. 001% , CaC12.2H2O 0.002%. The fermentation conditions are 30℃ for 20 h, 160 rpm, initial pH 6.5 and 4% of inoculation. Under this optimized conditions, the nitrite reductase activity reached 45.94 U/mL.