Keratinolytic protease: a green biocatalyst for leather industry
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Depilation/unhairing is the crucial but heavy pollution process in leather industry. Traditional inorganic sulfide treatment was the most widely used depilation technique in the past decades, which was usually detrimental to leather quality and resulted in serious environmental pollution. Using biocatalysts to substitute inorganic sulfide showed great advantages in environment protection and unhairing efficiency. Keratinolytic protease is one of the excellent biocatalysts to hydrolyze disulfide bond-rich proteins of hair and has little damage to leather. Biological treatment with keratinolytic proteases could largely reduce the quantity and toxicity of wastewater effluent from the leather industry. But low thermostability and substrate specificity or specific activity of these enzymes limited their practical application. Therefore, recent progresses on protein engineering strategies (site-directed mutagenesis, protein fusion, N/C-terminus truncation, and domain swapping) used to enhance the keratinolytic enzyme performance were presented.
KeywordsUnhairing process Enzymatic catalyst Industrial biotechnology Protein engineering Lime sulfide free Keratinolytic proteases
This work was supported by the project of Integration of Industry, Education, and Research of Jiangsu Province, China (BY2016022-39), supported by the National Natural Science Foundation of China (31470160), supported by the Major State Basic Research Development Program of China (973 Program, 2013CB733902); this work was also supported by Natural Science Foundation of Jiangsu Province (BK20160015) and a project funded by the Priority Program Development of Jiangsu Higher Education Institutions.
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Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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