Studies on the production of enzymes by white-rot fungi for the decolourisation of textile dyes

Four white- rot fungi, Bjerkandera adusta, Phlebia tremellosa, Pleurotus ostreatus and Coriolus versicolor, were tested for their ability to produce Lignin Peroxidase (LiP), Manganese Peroxidase (MnP), and Laccase in a nitrogen deficient mineral salts medium. B. adusta and P. tremellosa were selected, due to their high peak enzyme activities, for the degradation of 5 dyes in an artificial textile-effluent. Degradation experiments were carried out in N-rich (C:N ratio, 11.6:1) and N-limited, 116:1) conditions at a dye concentration of 100 mg/liter. B. adusta degraded 85% of the dyes in 7 days and P. tremellosa 79% in 9 days in N-rich media. 86% of the effluent was degraded in 9 days by B. adusta and 74% by P. tremellosa in 11 days in N-limited conditions. Addition of nitrogen had no substantial effect on percentage dye degradation by B. adusta, with a slight increase for P. tremellosa. Nitrogen supplementation did however reduce the decolourisation time. The results show the potential of using B. adusta and P. tremellosa for textile- effluent degradation, with or without nitrogen supplementation.