Discoloration of textile dyes by spent mushroom substrate of Agaricus bisporus

The textile industry discharges up to 5 % of their dyes in aqueous effluents. Here, use of spent mushroom substrate (SMS) of commercial white button mushroom production and its aqueous extract, SMS tea, was assessed to remove textile dyes from water. A total of 30-90 % and 5-85 % of the dyes was removed after a 24 h incubation in SMS and SMS tea, respectively. Removal of malachite green and remazol brilliant blue R was similar in SMS and its tea. In contrast, removal of crystal violet, orange G, and rose bengal was higher in SMS, explained by sorption to SMS and by the role of non-water-extractable SMS components in discoloration. Heat-treating SMS and its tea, thereby inactivating enzymes, reduced dye removal to 8-58 % and 0-31 %, respectively, indicating that dyes are removed by both enzymatic and non-enzymatic activities. Together, SMS of white button mushroom production has high potential to treat textile-dye-polluted aqueous effluents.