Mycoremediation of phenols and polycyclic aromatic hydrocarbons from a biorefinery wastewater and concomitant production of lignin modifying enzymes

This study assessed the ability of seven fungal strains to remove phenols and produce enzymes from a non-sterilized pH 7.0 biorefinery wastewater (BRW) resulting from the valorization of treated wood biomass. Two strategies using glucose and woodchips at low concentrations (4 g L-1) were studied. The chemical characterization of the BRW revealed the presence of a significant concentration of some toxic organic and inorganic compounds (chlorophenols, polycyclic aromatic hydrocarbons and heavy metals). Compared to biosorption, biotransformation was the primary mechanism involved in the elimination of the contaminants. Mycoremediation, usingPleurotus dryinus and Trametes hirsuta, achieved high dephenolization yields (94% and 100%, respectively), contributed to the removal of some other organic and inorganic compounds, and concomitantly produced laccase in the BRW. The use of lignocellulosic waste material as the carbon source contributed to decreasing the cost of the culture medium but not the final cost of laccase production. The laccase production cost estimate showed that Strategy 1, which used the most expensive medium (with glucose), was 60-fold and 4-fold less expensive for Pleurotus dryinus and Trametes hirsuta, respectively, than Strategy 2, which used woodchips. The processing time was a crucial parameter to consider for achieving cost-effective of laccase production from sustainable BRW mycoremediation.