Protease enzyme based cleaner leather processing: A review

Leather processing has been a part of people's needs since the beginning of civilization. The demand for leather has constantly pushed this sector to improve processing techniques with time. Every year, about seven million tons of salted hides and skins are used for leather manufacture across the world. However, the high concentrations of chemicals used in the processing of animal skins make the sector a potential hazard to the environment. For a long time, numerous natural enzymes have been attempted to investigate in leather processing to replace chemicals, although complete chemical substitution by enzymes has yet to be done. Proteases are arguably the most extensively utilized enzymes for dehairing hides and skins. Some researchers have utilized them in soaking, rehydration, pickling, and chrome tanning. The search for new protease sources prompted researchers to focus on enzyme engineering utilizing recombinant and immobilization technology. The goal of this review is to compile the most important aspects of using proteases in leather processing as a cleaner alternative technology that will lead to a more sustainable and environmentally friendly leather industry.