Development of a Novel and Efficient HCDC Process for heterologous production of Ambystoma Mexicanum Epidermal Lipoxygenase (AmbLOXe) in E. coli

LOXe enzyme is responsible for the regrowth of severed limbs and is a new candidate in wound healing. This study developed an efficient feeding approach in the fed-batch culture of E. coli with the maximum achievable specific growth rate to obtain higher production and productivity. In this method, the specific growth rate before the induction of the TB culture medium was maintained at a maximum of 0.92 ± 0.2 h-1. Then, with the simultaneous initiation of induction and feeding, due to system limitations, the specific growth rate decreased over time until it reached less than 0.1 until growth finally stopped. The complex medium containing glucose 200 g/l and yeast extract 200 g/L was used as the feeding medium. Using this strategy, the total production and productivity of LOXe increased from 5.4 to 27.35 g/L and from 0.527 to 2.19 g/L, respectively, compared to batch culture. By investigating the effect of glucose and yeast extract concentrations in the feeding medium, despite the 50% decrease in yeast extract, recombinant enzyme production increased by about 10% from 27.35 to 30.43 g/L. Finally, optimization of the inducer amounts increased rLOXe production (20% increase) to 36.4 g/L and overall efficiency to 2.71 (11.5% increment). This is one of the highest productivities ever reported for the recombinant protein production of E. coli.