ENHANCED ENZYMATIC REMOVAL OF CHLOROPHENOLS IN THE PRESENCE OF CO-SUBSTRATES

The effect of reactive co-substrates such as guaiacol and 2,6-dimethox yphenol on the removal of chlorinated phenols by horseradish peroxidas e (HRP) and a laccase from the fungus Trametes versicolor was investig ated. Addition of 50 mM guaiacol enhanced the precipitation of 4-chlor ophenol, 2,4-dichlorophenol, and 2,4,5-trichlorophenol with peroxidase by 12, 32 and 65%, respectively, and with laccase by 20, 32 and 80%, respectively. Addition of 10 mM 2,6-dimethoxyphenol enhanced the preci pitation of 2,4.5-trichlorophenol by 90% with peroxidase and by 98% wi th laccase. Products from the reaction of 2,6-dimethoxyphenol and pero xidase were filtered to exclude compounds of a molecular weight greate r than 500. Incubation of the resulting enzyme-free filtrate with a so lution of unreacted 2,4,5-trichlorophenol caused precipitation and a 7 2% removal of the 2,4,5-trichlorophenol. Chlorophenol precipitation in the presence of co-substrates may be a useful strategy for improving the efficiency of enzymatic decontamination methods, particularly in t he case of heterogeneous pollution.