Evaluation of solid substrates for enzyme production by Coriolus versicolor, for use in bioremediation of chlorophenols in aqueous effluents

In the development of a system for the removal of chlorophenols from aqueou s effluents, a range of solid substrates for the growth of Coriolus versico lor were investigated. Substrates included wood chips, cereal grain, wheat husk and wheat bran. Suitability for transformation of chlorophenols depend ed on laccase production by the fungus. The greatest amount of laccase (< 2 5 Units g(-1) substrate) was produced on wheat husk and wheat bran over 30 days colonisation. Aqueous extracts of laccase from wheat husk and wheat br an cultures removed 100% of 2,4-dichlorophenol (50 ppm) from solution withi n 5 h and 75-80% of pentachlorophenol (50 ppm) within 24 h. Wheat bran was formulated into pellets with biscuit flour to provide a compact substrate f or fungal immobilisation. Addition of 8-12% yeast extract to the pellets in creased laccase production five-fold. Colonised pellets were added to chlor ophenol solutions in 200-4000-ml bioreactors, resulting in > 90% removal of chlorophenols within 100 min.