Preparation and characterization of porous cross linked laccase aggregates for the decolorization of triphenyl methane and reactive dyes

The production of porous cross-linked enzyme aggregates (p-CLEAs) is a simple and effective methodology for laccase immobilization. A three-phase partitioning technique was applied to co-precipitate laccase and starch, followed by cross-linking with glutaraldehyde and removal of starch by alpha-amylase to create pores in the CLEAs. Scanning electron microscopy revealed a very smooth spherical structure with numerous large pores. The half-life of free laccase at 55 degrees C was calculated to be 1.3 h, while p-CLEAs did not lose any activity even after 14 h. p-CLEAs also exhibited improved storage stability, catalytic efficiency and could be recycled 15 times with 60% loss of activity. The catalysts decolorized triphenylmethane and reactive dyes by 60-70% at initial dye concentrations of 2 and 0.5 g L-1, respectively, without any mediators. These results suggest the potential of CLEA technology in waste-water treatment. (C) 2012 Elsevier Ltd. All rights reserved.