ENHANCED PRODUCTION OF LACCASE BY MICROPARTICLE INDUCED CULTIVATION OF BASIDIOMYCETES AND EVALUATION OF ITS EFFICIENCY AS DEINKING AGENT

Abstract

Recycling paper is worthy alternative to cut down the dependence on trees thereby preventing the hazards like deforestation. Deinking is an important step in the recycling process which involves the removal of ink particles from fiber surface and decolorization of the dislodged ink. Enzymes such as laccases may prove eco-friendly cost effective alternatives to the conventional chemicals methods used for the recycling process. However, the commercial application of this enzyme is limited by insufficient production and less stability. Hence, in this study, the laccase produced by basidiomycetes species, P. ostreatus was evaluated for its potential as a deinking agent. P. ostreatus was able to grow on many cheap substrates and when grown in the medium containing sawdust showed significant laccase production. Addition of 5g/L of Al2O3 microparticles (microparticle enhanced cultivation) improved the production of laccase. The maximum activity of P. ostreatus laccase was observed at pH 3 and at 28˚C. Activity was further stabilized by incorporation of Copper ions and immobilization in Ca-alginate beads. The enzyme was capable of decolorizing ink from color printer cartridge and from low quality coloured papers such as bus tickets. The brightness of the handsheets made from pulp was more pronounced than those treated with chemicals.