Microbiology and Industrial Biotechnology of Food-Grade Proteases: A Perspective

Summary Recent developments in industrial biotechnology have resulted in the exploitation ofnew and undiscovered microorganisms and the devising of improved methods for en-zyme production, which have led to increased yields of the enzyme, thus making a viableindustrial process feasible. This review tracks the developments in the field of acidic andneutral protease production with regard to the producers, methods of production andtheir improvement, the product and its applications. Key words : neutral protease, acidic protease, fermentation, genetic engineering, purifica-tion, enzyme assay Introduction Proteases are one of the industrially most importantenzymes. These proteolytic (protein digesting) biocata-lysts have been in use for many centuries, at first in thedairy industry as milk-clotting agents (rennet) for themanufacture of cheese. Proteases are enzymes that cata-lyse hydrolytic reactions in which protein molecules aredegraded to peptides and amino acids. These constitutea very large and complex group of enzymes, which dif-fer in properties such as substrate specificity, active siteand catalytic mechanism, pH and temperature optima andstability profile. The specificity of proteolytic enzymes isgoverned by the nature of the amino acid and other func-tional groups (aromatic or aliphatic or sulphur-contain-ing) close to the bond being hydrolysed. Proteases arepresent in all living beings and play an important rolein normal and abnormal physiological conditions, cata-lysing various metabolic reactions (