Optimization of Culture Medium for Nitrite Reductase Produced by Genetic Engineering Bacteria E.coli pET-28a(+)-nir-BL21

Bacillus cereus LJ01,isolated from bean paste with efficient nitrite degradation was used to construct the recombinant strain pET-28a(+)-nir-BL21 with the corresponding expression vectors of nir gene. In order to improve the production of nitrite reductase(NiR)of pET-28a(+)-nir-BL21,the composition of culture medium was preliminarily optimized. The optimum medium conditions were obtained by single factor test,Plackett-Burman and Box-Behnken experiment. The results showed that the optimum medium were:The liquid LB medium as the base medium,followed by 3.72 g·L^-1 glucose,2.63 g·L^-1 glycerol and 8.70 g·L^-1 peptone. The verified number of viable cells was 3.02×10⁸ CFU·mL^-1,which was close to the predicted value(3.14×10⁸ CFU·mL^-1). The high-yield nitrite reductase strain constructed in this experiment would provide a theoretical basis for industrial application of nitrite in food degradation in the future.