Optimization of DsbA Purification from Recombinant Escherichia coli Broth Using Box-Behnken Design Methodology

Disulfide bond formation protein A (DsbA) is one of the important helper proteins for folding in protein synthesis in vivo. In this study, purification of recombinant DsbA was investigated by examining four important factors with Box-Behnken design method, a statistic-based design of experiments. The optimal operation conditions were obtained by adopting the effectiveness coefficient method on the multi-objective problem, which takes the protein recovery, purification efficiency and throughput of ion-exchange chromatography into account. After the optimization, protein recovery of 96.8% and purity higher than 95% DsbA was achieved, and the productivity was (377.9±1.7) mg soluble DsbA per liter broth. The purified protein was identified by peptide mass fingerprinting matching the record of gi|2624856, a mutant of DsbA. The DsbA was preliminarily applied to the refolding of denatured lysozyme in vitro.