PCB’s Biotransformation by a White-Rot Fungus Under Composting and Liquid Culture Conditions

Abstract

The white-rot fungus Phanerochaete chrysosporium H-298 CDBB-500 was able to dechlorinate the polychlorinated biphenyl (PCB's) congeners. In this study, the extent of transformation and the ligninolytic enzymes involved in PCB transformation were compared between the composting and liquid cultures. Compo sting culture (Ce) showed a higher CO2 evolution when fungal inoculum was present than those containing only the native microflora. The fungus and the native community showed synergistic effects as demonstrated by the increase of CO2 production and PCB transformation. The added fungi and the native microflora transformed around 70 % of the PCB congeners. In the other hand, the extent of PCB degradation by the fungus was 85 % in the liquid culture (Le). There was a direct correlation between PCB degradation and fungal growth. In both systems (LC and Ce), the highly chlorinated congeners were transformated, while the less chlorinated congeners increased during the treatment, suggesting a possible dechlorination process. Mn dependent peroxidase (MnP) was detected in both systems, while lignin peroxidase (LiP) was detected only in LC. MnP is suggested to be involved in PCB transformation.