title: 5-hydroxymethylfurfural conversion by fungal aryl-alcohol oxidase and unspecific peroxygenase.
abstract: Oxidative conversion of 5-hydroxymethylfurfural (HMF) is of biotechnological interest for the production of renewable (lignocellulose-based) platform chemicals, such as 2,5-furandicarboxylic acid (FDCA). To the best of our knowledge, the ability of fungal aryl-alcohol oxidase (AAO) to oxidize HMF is reported here for the first time, resulting in almost complete conversion into 2,5-formylfurancarboxylic acid (FFCA) in a few hours. The reaction starts with alcohol oxidation, yielding 2,5-diformylfuran (DFF), which is rapidly converted into FFCA by carbonyl oxidation, most probably without leaving the enzyme active site. This agrees with the similar catalytic efficiencies of the enzyme with respect to oxidization of HMF and DFF, and its very low activity on 2,5-hydroxymethylfurancarboxylic acid (which was not detected by GC-MS). However, AAO was found to be unable to directly oxidize the carbonyl group in FFCA, and only modest amounts of FDCA are formed from HMF (most probably by chemical oxidation of FFCA by the H2 O2 previously generated by AAO). As aldehyde oxidation by AAO proceeds via the corresponding geminal diols (aldehyde hydrates), the various carbonyl oxidation rates may be related to the low degree of hydration of FFCA compared with DFF. The conversion of HMF was completed by introducing a fungal unspecific heme peroxygenase that uses the H2 O2 generated by AAO to transform FFCA into FDCA, albeit more slowly than the previous AAO reactions. By adding this peroxygenase when FFCA production by AAO has been completed, transformation of HMF into FDCA may be achieved in a reaction cascade in which O2 is the only co-substrate required, and water is the only by-product formed.
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Carro
authors.affiliation: Facultad de Ciencias and Instituto de Biocomputación y Física de Sistemas Complejos, Zaragoza, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ferreira
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Leonor
authors.initials: L
authors.lastname: Rodríguez
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Prieto
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Serrano
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Balcells
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Ardá
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Jiménez-Barbero
authors.affiliation: Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Gutiérrez
authors.affiliation: Department of Bio- and Environmental Sciences, International Institute of Zittau, Germany.
authors.forename: René
authors.initials: R
authors.lastname: Ullrich
authors.affiliation: Department of Bio- and Environmental Sciences, International Institute of Zittau, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hofrichter
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Angel T
authors.initials: AT
authors.lastname: Martínez
mesh_terms: D055362:Agrocybe / Q000201:enzymology; D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D020134:Catalytic Domain; D005656:Fungal Proteins / Q000378:metabolism*; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008031:Lignin / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010084:Oxidation-Reduction; D020076:Pleurotus / Q000201:enzymology; D059205:Renewable Energy; D014867:Water / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D014867:Water; C036909:lignocellulose; C008046:5-hydroxymethylfurfural; D008031:Lignin; D005662:Furaldehyde; D006899:Mixed Function Oxygenases; D000429:Alcohol Oxidoreductases; C077759:aryl-alcohol oxidase; C022333:peroxygenase
keywords: 2,5-formylfurancarboxylic acid; 2,5-furandicarboxylic acid; 5-hydroxymethylfurfural; aryl-alcohol oxidase; unspecific peroxygenase