Biodegradation of Congo Red by Phanerochaete chrysosporium

The azo dye Congo Red, was degraded extensively by the wood rotting basidiomycete, Phanerochaete chrysosporium in agitated liquid cultures and in solid malt agar cultures. Upon addition of Congo Red to agitated liquid cultures, the dye was adsorbed to the mycelial pellets in both ligninolytic and non-ligninolytic cultures followed by extensive degradation only in the ligninolytic cultures. This fungus, grown from conidiospores, readily degraded up to 718 μM (500 mg/l) Congo Red in 2.0% malt agar. Decolorization of Congo Red in malt agar plates was suppressed by the addition of supplemental nutrient nitrogen indicating that the lignin degrading system of P. chrysosporium may be important in the biodegradation of this dye. This is supported by the observation that Congo Red is a substrate for purified lignin peroxidase H8. These results are of interest because it had been previously reported that Congo Red was not a substrate for lignin peroxidase nor was it extensively degraded by this fungus.