Microbial keratinases: An overview of biochemical characterization and its eco-friendly approach for industrial applications

The environment is under constant threat due to the huge accumulation of the keratinaceous wastes produced by poultry processing industries and poultry farms. Millions of tons of feather wastes are produced each year as a by-product that causes severe environmental pollution. Their degradation is tough due to the presence of insoluble, highly stiff, recalcitrant ‘keratin’ polypeptide. Keratin are resistant to degradation by common proteases and chemical catalysts due to high mechanical stability and cross-linked disulphide bonds present in their structure. Microbial keratinases has emerged as a powerful bio-catalyst that can potentially degrade keratin and transform the keratinaceous wastes into value-added products. Keratinase production is receiving worldwide attention for its application in sustainable development and cleaner production. The enzymatic hydrolysis of keratin have the potential for higher productivity, less energy consumption, less effluent generation and waste management. Keratinases add value to poultry and industrial wastes which brings economic feasibility and environmental sustainability. The present review prioritized the various aspects of keratinolytic proteases in bringing sustainable development to the economy of a nation. It also focuses on the recent advancement in the production of microbial keratinases with emphasis on the biochemical characteristics related to enzyme activity and stability, development of novel recombinant and mutant microbial strains along with different optimization strategies leading to expansive production and yield of keratinases. Furthermore, different properties of microbial keratinases which renders them as a green and sustainable material for industrial applications in waste management, textile, leather and detergents with advantages over conventional treatments have also been discussed.