title: Potential of Wood-Rotting Fungi to Attack Polystyrene Sulfonate and Its Depolymerisation by Gloeophyllum trabeum via Hydroquinone-Driven Fenton Chemistry.
abstract: Synthetic polymers often pose environmental hazards due to low biodegradation rates and resulting accumulation. In this study, a selection of wood-rotting fungi representing different lignocellulose decay types was screened for oxidative biodegradation of the polymer polystyrene sulfonate (PSS). Brown-rot basidiomycetes showed PSS depolymerisation of up to 50 % reduction in number-average molecular mass (Mn) within 20 days. In-depth investigations with the most efficient depolymeriser, a Gloeophyllum trabeum strain, pointed at extracellular hydroquinone-driven Fenton chemistry responsible for depolymerisation. Detection of hydroxyl radicals present in the culture supernatants showed good compliance with depolymerisation over the time course of PSS degradation. 2,5-Dimethoxy-1,4-hydroquinone (2,5-DMHQ), which was detected in supernatants of active cultures via liquid chromatography and mass spectrometry, was demonstrated to drive the Fenton processes in G. trabeum cultures. Up to 80% reduction in Mn of PSS where observed when fungal cultures were additionally supplemented with 2,5-dimethoxy benzoquinone, the oxidized from of 2,5-DMHQ. Furthermore, 2,5-DMHQ could initiate the Fenton's reagent-mediated PSS depolymerisation in cell-free systems. In contrast, white-rot fungi were unable to cause substantial depolymerising effects despite the expression of lignin-modifying exo-enzymes. Detailed investigations with laccase from Trametes versicolor revealed that only in presence of certain redox mediators limited PSS depolymerisation occurred. Our results indicate that brown-rot fungi might be suitable organisms for the biodegradation of recalcitrant synthetic polymeric pollutants.
authors.affiliation: Department Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Krueger
authors.affiliation: Department Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hofmann
authors.affiliation: Department Analytical Chemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Moeder
authors.affiliation: Department Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schlosser
mesh_terms: D001487:Basidiomycota / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry; D001673:Biodegradation, Environmental; D002474:Cell-Free System / Q000737:chemistry; D005658:Fungi / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006873:Hydroquinones / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry; D010084:Oxidation-Reduction; D058105:Polymerization; D011137:Polystyrenes / Q000737:chemistry*; D014934:Wood / Q000382:microbiology*
chemical_list: D016227:Benzoquinones; C045076:Fenton's reagent; D006873:Hydroquinones; D011137:Polystyrenes; C036909:lignocellulose; C004532:quinone; C003321:polystyrene sulfonic acid; D008031:Lignin; D006861:Hydrogen Peroxide; D007501:Iron; C031927:hydroquinone