Biodegradation of chlorolignin and lignin-like compounds contained in E-1-pulp bleaching effluent by fungal treatment

The ligninolytic system from the fungi Trametes villosa and Panus crinitus can efficiently degrade all fractions of different molecular mass contained in El-bleaching effluent, but with different degradation rates. The lower- molecular-mass (MM) materials were better characterized when the elution in the size-exclusion high-performance liquid chromatography were monitored a t 210 than at 280 nm, which indicates that these compounds may be ring clea vage byproducts from depolymerized chlorolignin. The biodegraton of E-1 eff luent by both fungi was a multistage process, involving an initial chemical modification of the higher-MM compounds and concomitant oxidation of the l ower-MM materials. A subsequent depolymerization of chemically modified pol ymeric lignin-like compounds also took place. Each stage may require one or several different enzymes. The results suggested that laccase was involved in the initial stage.