Production of a new sea anemone neurotoxin by recombinant Escherichia coli: Optimization of culture conditions using response surface methodology

Culture conditions for the production of sea anemone hk2a fusion protein by recombinant Escherichia coli DE3 were optimized using response surface methodology based on the central composite design (CCD). The culture conditions included initial pH of culture, IPTG concentration, induction start time, post-induction time and temperature. In additions to reducing the number of experiments required for optimization, this design also allows the quantification of the cloned protein content in any part of the experimental domain. The optimal set of culture conditions for high soluble hk2a fusion protein was determined: initial pH of culture 8.0, 0.1 mM IPTG, an induction start time of 1.56 h, a post-induction time of 9.92 h, and a post-induction temperature of 22 °C. The recombinant E. coli produced about 10% soluble fusion protein in the optimized conditions.