Biodegradation kinetics of chlorophenols in immobilized‐cell reactors using a white‐rot fungus on wood chips: Fid-Bau Portal

Biodegradation kinetics of chlorophenols in immobilized‐cell reactors using a white‐rot fungus on wood chips

Yum, Kyu‐Jin / Peirce, J. Jeffrey

This research investigated the ability of wood‐chip reactors seeded with a white‐rot fungus (Phanerochaete chrysosporium) to degrade hazardous substances (4‐chlorophenol [4‐CP] and 2,4‐dichlorophenol [2,4‐DCP]). Batch‐reactor tests were conducted using 4‐CP as a model compound to evaluate the effect of carbon and nitrogen deficiencies on the ability of white‐rot fungus immobilized on wood chips to degrade 4‐CP. The white‐rot fungus degraded 4‐CP (71.1 to 83.0%) under all tested conditions including the non‐glucose and non‐nitrogen conditions. However, there are differences in the degradation percentage of 4‐CP using the different growing conditions. The degradation of 4‐CP occurs to the greatest extent in the non‐glucose/with‐nitrogen condition (15.38 ppm/h·g of specific biodegradation rate). Continuous‐flow packed‐bed reactor tests are conducted using 2,4‐DCP as a model compound to evaluate the inhibition effect of 2,4‐DCP on the biodegradation enzymes in wood‐chip reactor systems, and the inhibition effects seem to be present. The inhibition kinetics of 2,4‐DCP are successfully modeled with the mass‐balance equation of plug‐flow reactors and a substrate‐inhibition equation for the reaction rate, yielding an inhibition constant,K_i of 69.8 ppm and a maximum 2,4‐DCP concentration, [S]_max, of 48.9 ppm at the highest reaction rate. The importance of these results is that the substrate‐inhibition model can be used to explain the inhibition effect of 2,4‐DCP on the biodegradation enzymes in this wood‐chip reactor system. This study points to the potential of continuous‐flow reactors using wood chips as a carbon source to degrade toxic chemicals with high‐degradation efficiency.