Production, characterization, and application of a new chymotrypsin-like protease from Pycnoporus sanguineus

Abstract

Proteases are the most commercialized enzymes and are widely used in industrial processes, especially in the dairy industry. Cheese production is increasing disproportionately to the availability of calf rennet, the main coagulant used in this process. In addition to the cost of rennet, there is also a religious and dietary objection to the use of calf proteases. An alternative is the production of microbial enzymes via solid state fermentation (SSF), which uses agroindustrial residues as a source of nutrients and substrate. To obtain proteases with milk-clotting activity, Pycnoporus sanguineus was produced via SSF using agroindustrial residue wheat bran as the culture medium. Caseinolytic activity and maximum enzyme production were obtained after 96 h of cultivation. The protease was identified as a chymotrypsin-like serine protease after testing it against specific substrates and inhibitors. The protease from P. sanguineus had a specific activity of 741.3 U mg⁻¹ and was able to coagulate reconstituted skim milk and whole milk, with and without the addition of calcium. Coagulation was affected by time, temperature, and calcium and enzyme concentrations. Therefore, we describe herein for the first time a protease obtained from P. sanguineus, a chymotrypsin-like serine protease with milk-clotting activity that has potential applications in the dairy industry.

Keywords:

• Agroindustrial residues
• milk coagulation
• serine protease
• solid state fermentation

Acknowledgements

The authors are grateful to the Brazilian Ministry of Education’s Coordination for the Improvement of Higher Education Personnel (CAPES), the Brazilian National Council for Scientific and Technological Development (CNPq) and the Alagoas State Research Foundation (FAPEAL) for funding this research.

Disclosure statement

The authors report no conflict of interest.