ENZYMATIC REMOVAL OF MELANIN IN ENZYME BASED DEHAIRING AND FIBER OPENING

Abstract

Melanin is a natural pigment of skin and hair which provides a protective function against sunlight. The non-removal of pigments from the skin gives the finished leather a patchy appearance. As the leather industry is undergoing a paradigm shift towards bioprocessing, enzyme based dehairing and fiber opening are becoming ecologically important. However, the enzymatic dehairing and fiber opening of buffalo calfskins results in non-removal of pigments. In this study, an attempt has been made to remove the pigments from buffalo calfskins using xylanase. Xylanase is a hydrolase which is generally used for bleaching of wood and pulps. The presence of melanin in enzymatically dehaired buffalo calfskins was identified through UV-visible spectral analysis. Preliminary trials have been carried out for removing melanin with various concentrations of xylanase in enzymatic dehairing and fiber opening. Addition of xylanase provides complete removal of melanin during enzymatic dehairing as well as fiber opening. Semi-technical trials have been performed by employing xylanase during enzymatic dehairing and fiber opening individually. The removal of melanin was found to be 100%. The performance characteristics of the resulted leathers have been analyzed and found satisfactory. RESUMEN: La melanina es un pigmento natural de la piel y del cabello que proporciona una funcion de proteccion contra la luz solar. La no eliminacion de los pigmentos de la piel da al cuero acabado un aspecto irregular. Como la industria del cuero esta experimentando un cambio de paradigma hacia el bioprocesamiento, los pelambres y la apertura fibrilar basado en enzimas estan siendo de importancia ecologica. Sin embargo, la apertura fibrilar y el pelambre enzimatico de pieles de bufalo no resuelve la eliminacion de los pigmentos. En este estudio, se ha tratado de eliminar los pigmentos de pieles de bufalos utilizando xilanasa. Xilanasa es una hidrolasa que generalmente se utiliza para la decoloracion de madera y pulpa para papel. La presencia de melanina en la pieles de bufalo apelambradas enzimaticamente fue identificada a traves de analisis espectroscopico en visible-UV. Ensayos preliminares se han llevado a cabo para la eliminacion de melanina con varias concentraciones de xilanasa en la apertura de fibras y pelambre enzimatico. La adicion de xilanasa ofrece una eliminacion completa de la melanina durante el pelambre enzimatico, asi como en la apertura de la fibra. Ensayos semi-tecnicos se han realizado empleando xilanasa durante el pelambre enzimatico y apertura fibrilar individualmente. La eliminacion de melanina resulto ser del 100%. Las caracteristicas de rendimiento en los cueros resultantes han sido analizadas y se encontraron satisfactorias.