Removal of TBP sorbed on wood by Trametes versicolor through solid-state fermentation

Abstract

Altres ajuts: acords transformatius de la UAB

The use of white-rot fungi is a promising approach for removing organophosphate flame retardants (OPFRs) from wastewaters. Immobilization in wood for this purpose ensures the predominance of the fungus but also contributes to OPFRs sorption. This work focused on the ability of T. versicolor to degrade tributyl phosphate (TBP) sorbed in wood. This initially underwent ten sorption cycles, each involving exposure to a 10 mg·L-1 TBP solution. Throughout each cycle, the wood exhibited a sustained sorption capacity (0.035 ± 0.002 mg TBP·g. dry wood-1 per cycle). The wood residues obtained after each sorption cycle were inoculated with T. versicolor. After 60 days of inoculation, fungus degraded over 90 % of TBP in each cycle's wood residue. However, fungal growth was inhibited, resulting in a 43 % decrease in biomass compared to controls. The fact that biomass remained active and capable of degrading TBP suggests that the growth decrease is likely due to the formation of transformation products. An increase in toxicity units (from 13.64 to 87.86 at the end) was associated with the accumulation of 3-hydroxybutyl dihydrogen phosphate (OH-MBP). However, subsequent experiments demonstrated that given sufficient time, the fungus not only degraded OH-MBP but also produced a non-toxic effluent.