title: Extracellular electron transfer systems fuel cellulose oxidative degradation.
abstract: Ninety percent of lignocellulose-degrading fungi contain genes encoding lytic polysaccharide monooxygenases (LPMOs). These enzymes catalyze the initial oxidative cleavage of recalcitrant polysaccharides after activation by an electron donor. Understanding the source of electrons is fundamental to fungal physiology and will also help with the exploitation of LPMOs for biomass processing. Using genome data and biochemical methods, we characterized and compared different extracellular electron sources for LPMOs: cellobiose dehydrogenase, phenols procured from plant biomass or produced by fungi, and glucose-methanol-choline oxidoreductases that regenerate LPMO-reducing diphenols. Our data demonstrate that all three of these electron transfer systems are functional and that their relative importance during cellulose degradation depends on fungal lifestyle. The availability of extracellular electron donors is required to activate fungal oxidative attack on polysaccharides.
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kracher
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Scheiblbrandner
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Alfons K G
authors.initials: AK
authors.lastname: Felice
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Erik
authors.initials: E
authors.lastname: Breslmayr
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Marita
authors.initials: M
authors.lastname: Preims
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria. Institute of Technical Biochemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Lodz, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Ludwicka
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Haltrich
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway.
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
authors.affiliation: Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria. roland.ludwig@boku.ac.at.
authors.forename: Roland
authors.initials: R
authors.lastname: Ludwig
mesh_terms: D055162:Biocatalysis; D004579:Electron Transport; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D005658:Fungi / Q000201:enzymology* / Q000235:genetics; D016681:Genome, Fungal; D008031:Lignin / Q000737:chemistry*; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000235:genetics; D010084:Oxidation-Reduction
chemical_list: D005656:Fungal Proteins; C036909:lignocellulose; D008031:Lignin; D006899:Mixed Function Oxygenases