Abstract
In the present investigation, performance of various laccase-membrane reactor configurations including direct enzyme contact, enzyme impregnated, immobilized enzyme and a reactor system based on laccase immobilization in chitosan membranes for decolorization of azo dye (acid black 10 BX) were examined using laccase enzyme purified from white rot fungi
Pleurotus ostreatus 1804. A five-step laccase purification procedure was employed, which improved the enzymatic activity by 8.27 folds. Laccase was confirmed by comparing with the standard marker using SDS-PAGE electrophoresis, which showed molecular weight of 63
kDa. Experimental data showed that laccase has great potential for color removal without addition of external redox mediators. Various process parameters viz. aqueous phase of pH 6.0, enzyme concentration of 1.75
U/ml, dye concentration of 20
mg/L, temperature of 30
°C and reaction time of 120
min were optimized to achieve maximum decolorization efficiencies. Moreover, different laccase-membrane reactor configurations were tested to determine the efficacy of repeated application of laccase on dye decolorization process. Among the different reactor configurations employed, laccase encapsulated in chitosan membrane showed advantages such as short-term contact period and reusability of enzyme for a number of cycles.