Physical removal of textile dyes from effluents and solid-state fermentation of dye-adsorbed agricultural residues

Three agricultural residues, wheat straw, wood chips and corn-cob shreds were tested for their ability to adsorb individual dyes and dye mixtures in solutions. Up to 70–75% colour removal was achieved from 500 ppm dye solutions at room temperature using corn-cob shreds and wheat straw. Increasing the temperature had little effect on the adsorption capacity of the residues. The resulting dye-adsorbed residues were found to be suitable substrates for solid-state fermentation (SSF) by two white-rot fungi; Phanerochaete chrysosporium and Coriolus versicolor. Both strains grew uninhibited and produced a maximum protein content of 16, 25 and 35 g and 19, 23 and 50 g in SSF of 100 g dry weight wood chips, corn-cob shreds and wheat straw, respectively, supplemented with ammonical nitrogen to give a C:N ratio of 20:1. This approach provides preliminary results for the remediation of textile effluent and the conversion of agricultural residues into soil conditioner.