Decolorization and biodegradation of anaerobically digested sugarcane molasses spent wash effluent from biomethanation plants by white-rot fungi

Abstract

Four white-rot fungal cultures were examined for their ability to decolorize and bioremediate anaerobically digested molasses spent wash (DMSW) generated by biomethanation plants. Two cultures Coriolus versicolor and Phanerochaete chrysosporium showed an ability to decolorize and reduce the chemical oxygen demand (COD) of diluted DMSW (12·5% v/v). Both cultures required an additional labile carbon source to carry out decolorization while additional organic nitrogen did not significantly improve it further. Optimum growth and decolorization occurred at 35–40°C, pH 5·0, glucose at 3–5%(w/v). Maximum decolorization (71·5 and 53·5%) and COD reduction (90·0 and 73·0%) were achieved in 6·25% (v/v) DMSW medium by C. versicolor and P. chrysosporium, respectively. These values decreased significantly at higher concentrations of DMSW (12·5 and 25% v/v), nevertheless both cultures have profound potential applications in reducing the pollution of DMSW effluent prior to its disposal.