Fermentation Technologies for Protease Production: Submerged and Solid-State Fermentation

Proteases are among the most commercially important industrial enzymes, with wide-ranging applications in detergents, food processing, pharmaceuticals, textiles, leather processing, and environmental management. The large-scale microbial production of proteases is primarily based on two fermentation processes which are submerged fermentation (SmF) and solid-state fermentation (SSF). SmF entails the growth of microorganisms in a liquid nutrient medium with microorganisms, such as the Bacillus subtilis, Bacillus licheniformis, and Aspergillus niger. Process optimization focuses on the supply of carbon, nitrogen, and minerals, while efficient bioreactor design aims to control parameters such as aeration, agitation, temperature, and foam management in order to develop a high enzyme titer. SSF utilizes low-moisture conditions and agro-industrial residues as solid substrates, promoting the growth of microorganisms such as Aspergillus oryzae, Rhizopus spp., and Bacillus spp. Optimization of solid-state fermentation (SSF) process parameters, such as moisture content, temperature, and aeration, significantly improves productivity and cost-effectiveness. Comparative analysis of submerged fermentation (SmF) and SSF reveals varying advantages and disadvantages impacting yield and scalability. Enhanced protease production involves optimizing media formulation, pH, and moisture content, along with filtration and chromatography for recovery. Further strategies are needed to increase yields and manage issues like contamination in SmF and process variability in SSF. Future prospects include utilizing new microbial strains, designing innovative bioreactors, and integrating enzyme production into sustainable bioeconomy systems. This chapter examines the production of microbial proteases using SmF and SSF, optimization strategies, downstream processing, industrial application of proteases, and challenges and future perspectives.