Degradation of Pentachlorophenol in Bench Scale Bioreactors Using the White Rot FungusPhanerochaete chrysosporium

Abstract

Biodegradation of pentachlorophenol by the white rot fungus Phanerochaete chrysosporium was investigated in three bench scale bioreactors: mechanically mixed suspended bioreactor, upflow fixed-film bioreactor, and fluidized bed bioreactor. PCP disappearance was enhanced by increased ligninase activity in a mechanically mixed suspended bioreactor after initial adsorption onto the mycelium. Live fungal cultures were able to degrade PCP in the sorbed phase. PCP degradation data in the upflow fixed-film bioreactor was rapid and adequately explained with a quasi-first order steady state model with a rate constant of 0.071 L/g biomass-hr.In the fluidized bed bioreactor, effluent PCP concentration varied slightly at hydraulic residence times of 5 to 90 minutes. The steady state PCP degradation first order rate constant was 0.1 L/g biomass-hr. Effluent PCP concentration was related to its influent concentration at a 5 minute hydraulic retention time. The PCP removal efficiency was 37 to 72% and improved by increasing hydraulic retention time and decreasing influent PCP concentration. The fluidized bed bioreactor using P. chrysosporium shows considerable promise for the degradation of PCP. Degradation was effective under conditions of short hydraulic residence time and the process was stable in the face of large variations in influent conditions.