Cloning, Expression and Structure Simulation of Keratinase From Bacillus Licheniformis Strain MZK05

Abstract

Aims: Bacillus licheniformis MZK-05 is a keratinolytic bacterium having potential in dehairing of leather and feather hydrolysis. The present study aimed at to improving the production level of keratinase through gene cloning and expression of recombinant keratinase. Methodology and results: Bacillus licheniformis MZK-05 produced an amplicon of 1,156 bp in a polymerase chain reaction while targeting the gene, kerA, responsible for the enzyme keratinase. The amplicon was subsequently cloned into the plasmid vector pGEX-6p-2 for expression in Escherichia coli BL21. A 58 kD GST-KerA fusion protein was expressed upon IPTG induction which was eventually cleaved by PreScission protease that produced a 39 kD protein. A corresponding increase in proteolytic (312 U/mL) and keratinolytic (196 U/mL) activity were observed with the expressed keratinase. Specific enzyme activities for protease and keratinase, an indication of efficiency of the enzyme, were 2621.84 U/mg and 1647 U/mg, respectively and the specific keratinase activity was the highest activity ever reported by any recombinant bacterial strain. Conclusion, significance and impact study: Since the production of keratinase by wild type strain is limited to a certain level, the industrial need could be met by improving the production level through gene cloning and expression of recombinant keratinase. In this connection, the cloning of kerA gene from B. licheniformis MZK-05 into pGEX-6p-2 vector, its expression in Escherichia coli BL21 host and prediction of 3-D model of the expressed protein were performed which will be the basis for industrial production of keratinase in Bangladesh.