Endogenous hydrolyzing enzymes: Isolation, characterization, and applications in biological processes

Abstract

Enzymes are the key substances responsible for a variety of biotechnological processes involved in the production of useful bioproducts. Malt and microbial species (bacteria, fungi, etc.) are the main sources of endogenous hydrolyzing enzymes (EHEs). EHEs are primarily involved in the digestion of complex substrates into simpler units and the resulting formation of biological products. Based on origin and substrate specificity, EHEs are categorized into cell wall-, starch-, protein-, lipid-, nucleic acid-, polyphenol-, and thiol-hydrolyzing enzymes. The substrate specificities and reaction mechanisms of individual EHEs and groups of EHEs have been verified through isolated and purified enzymes. A number of methods have been reported for high-yield, economically feasible isolation of enzymes. The endogenous enzymes contained in microbial cells are separated from cells, cellular fragments, and organelles through several cell lysis and separation methods. Analysis of the mechanism of action has revealed that most enzymes systematically undergo biological processes through a cascade of enzyme-specific reactions. The applications of these EHEs are involved in almost every aspect of human and animal life and are important in food, animal feed, textile, paper and pulp, fuel (energy), pharmaceutical, and chemical industries. In this chapter, we describe the origins, classes, isolation techniques, mechanisms, and applications of various EHEs with examples from updated literature.