Medium optimization for phytase production by recombinant Escherichia coli using statistical experimental design

Abstract

The production of E. coli WC7 phytase from a recombinant E. coli strain was optimized using a statistical experimental design approach. Two-level complete factorial designs with seven variables were used for the media optimization. In the first optimization step, the influence of disodium succinate, yeast extract, K2HPO4, NH4H2PO4, MgSO4, NaCl, and trace elements on phytase production was evaluated. As a result, disodium succinate, yeast extract, NH4H2PO4, NaCl, and the trace elements were found to have a positive influence on the phytase production, while K2HPO4 and MgSO4 had a negative influence. In the second step, the concentrations of disodium succinate and yeast extract were further optimized using central composite designs. The maximum phytase activity obtained was 234 U/ml using 15.9 g/l disodium succinate, 20 g/l yeast extract, 5 g/lK2HPO4, 10 g/l NH4H2PO4, 1.5 g/l MgSO4, 4 g/l NaCl, and 1.5 ml/l trace elements, which was about a 14-fold increase in comparison with that obtained using the basal medium.