Microbial Protease: Sources, Classification, Detection, and Applications

Microbial proteases, which hydrolyze protein peptide bonds, predominate the global enzyme market. Biocatalysts are primarily derived from bacteria, such as Bacillus sp. (especially the Alkaline protease-producing B. licheniformis and B. amyloliquefaciens), and fungi, like Aspergillus sp., Penicillium sp., and Mucor sp. Microbial proteases are classified by their catalytic mechanisms, their site of action on the protein substrates, and their optimal pH of activity. These enzymes must be detected and quantified using qualitative methods, such as the protein agar plate assay and radial diffusion assay, as well as highly sensitive quantitative methods that utilize chromogenic or fluorogenic synthetic substrates for characterization and application. Microbial proteases are widely utilized in various industries, enhancing their commercial value. They are essential detergents in bio-formulation additives for protein-based stain degradation. They aid in meat tenderization, dairy protein hydrolysis (for cheese and debittering), soy product processing, and beverage clarification. They also assist the leather industry in dehairing and bating hides, manage waste by treating protein-rich waste, facilitate bioremediation, and enhance the digestibility of animal feed and nutrient availability. The future of microbial proteases is promising due to advances in Biotechnology, including protein engineering for improved stability and specificity, metagenomic screening for novel enzymes from previously unculturable microbes, and more efficient fermentation processes. Molecular proteases are vital biocatalysts whose broad specificity, high catalytic efficiency, and sustainable production methods make them essential in many industrial sectors. This chapter examines the microbial proteases, their diverse sources, systematic classification, advanced detection methods, and purification techniques, as well as their wide-ranging industrial applications.