COMPARISON OF FUNGAL LACCASE PRODUCTION ON DIFFERENT SOLID SUBSTRATES, IMMOBILIZATION AND ITS DECOLORIZATION POTENTIAL ON SYNTHETIC TEXTILE DYES

Laccases are polyphenol oxidases that require O2 to oxidize phenols, polyphenols, aromatic amines and different non-phenolic substrates by one electron transfer resulting in the formation of reactive radicals. In the current study 2 laccase producing strains of Aspergillus sp., and Penicillium sp., isolated from natural sources were studied for their optimal production on 5 different solid substrates (wheat bran, rice bran, ground nut cake, coconut cake and sesame cake). Wheat bran was found to be the substrate in which both the fungal strains were able to produce an optimal quantity of laccase enzyme of up to 1.632 IU/ml and 2.0 IU/ml respectively. The enzyme was extracted from the solid substrate having 2.0 IU/ml of enzyme unit and was immobilized on sodium alginate. When this immobilized alginate was allowed to act on the synthetic textile dyes Re Red BSID, Re Yellow merl, Orange merl, Red m5B and indigo carmine a maximum of 92.16% of decolorization was observed for Re Yellow merl after 5 days. All the other dyes were reduced to more than 70 % using the immobilized beads after 5 days. Received on: 3rrd-Sept -2010 Revised on: 29th-Dec -2012 Accepted on: 15th- Feb-2012 Published on: 8th -Oct-2012