Two fractions containing the oxidase activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) were obtained using ion-exchange DEAE-Sepharose column chromatography of the culture fluid of white-rot fungus, Trametes versicolor. These two fractions can reduce the level of coplanar PCB congeners (Co-PCBs). The ABTS oxidase in the first fraction passed through the DEAE-Sepharose column. The ABTS oxidase in the second fraction was adsorbed to the column at <pH 5.6. Overall, the first fraction has a higher activity to reduce each level of Co-PCBs than the second fraction does. In equally chlorinated congeners, non-ortho congeners were less metabolized than ortho congeners; a 4-hydroxy-pentachlorobiphenyl (hydroxy PeCB) was more susceptible to metabolism than a structurally related non-hydroxy PeCB or HxCB.