Abstract: Response surface methodology was used to optimize the fermentation media of recombinant E. coli and to improve the production capacity of glutamate dehydrogenase which is key biocatalyst in reductive amination. Firstly, the single factor experiment was used to screen the optimal carbon source and nitrogen source, and then the Plackett-Burman design was used to evaluate the influencing degree for response value of related factors in original fermentation medium. The optimum medium components combination was further determined according to Box-Bohnken design and response surface analysis. The optimized medium was obtained: glycerol 11.3 g/L, yeast extract (Angel 905) 16.28 g/L, MgSO4·7H2O 0.63 g/L, Na2HPO4·12H2O 17.1 g/L, KH2PO4 3 g/L, NH4Cl 1.5 g/L, NaCl 0.5g/L. Under above conditions, the enzyme activity of glutamate dehydrogenase was 2.58 times higher than that of LB medium and reached 129.1U/mL, which significantly improved the preparing efficiency of enzyme catalyst.

Key words: glutamate dehydrogenase, Plackett-Burman design, response surface method analysis, optimization of medium