Enhanced Production Process of Recombinant Mature Serratiopeptidase in Escherichia coli Using Fed-Batch Culture by Self-Proteolytic Activity of Fusion Protein

Microbial enzymes are increasingly finding applications as therapeutics due to their targeted activity and minimal side effects. Serratiopeptidase, also known as a miracle enzyme, has already proved its potential as an anti-inflammatory, mucolytic, fibrinolytic, analgesic in many studies. A cost effective, bioreactor level production process has been described here comprising of the fed-batch fermentation to produce recombinant serratiopeptidase protein expressed as a fusion construct. High yield of cell mass as well as protein was obtained by the optimization of bioreactor parameters. The downstream solubilization and purification processes were also optimized to achieve maximum yield of pure, active serratiopeptidase protein. A final yield of 2.5 +/- 0.764 g L-1 of protein was obtained, having 8382 +/- 291 U mg(-1) of specific caseinolytic activity. Additionally, a novel, unexpected self-proteolytic activity of the enzyme that cleaves the N-terminal 6x His-SUMO fusion tag along with the enzyme propeptide, thus yielding a mature serratiopeptidase, was also found.