A promising inert support for laccase production and decolouration of textile wastewater by the white-rot fungus Trametes pubescesns.

Cubes of nylon sponge, cubes of polyurethane foam (PUF), cuttings of stainless steel sponges and the commercial carriers Kaldnes™ K1 were tested as inert supports for laccase production by the white-rot fungus Trametes pubescens under semi-solid-state fermentation conditions. The cultures operating with Kaldnes™ K1 led to the highest laccase activity (3667 U/l). In addition this support could be re-utilised, making the whole process more economical. Subsequently, the decolouration of simulated textile wastewater (STW) by T. pubescens grown on the different tested supports under semi-solid-state fermentation conditions was studied. Decolouration percentages around 66-80% were obtained in 96 h. It was found that STW decolouration was due to two mechanisms: laccase action (biodegradation) and adsorption onto fungal mycelium, save for the PUF cultures in which decolouration was mainly due to adsorption onto the support. Further, the decolouration of STW by Kaldnes™ K1 cultures in three successive batches of 96 h each was studied. Decolouration percentages of 51.3, 70.0 and 69.8%, were attained for each batch, respectively.