Pecularities and applications of aryl-alcohol oxidases from fungi

Abstract

Aryl-alcohol oxidases (AAOs) are FAD-containing enzymes that oxidize a broad range of aromatic as well as aliphatic allylic alcohols to aldehydes. Their broad substrate spectrum accompanied by the only need for molecular oxygen as cosubstrate and production of hydrogen peroxide as sole by-product makes these enzymes very promising biocatalysts. AAOs were used in the synthesis of flavors, fragrances, and other high-value-added compounds and building blocks as well as in dye decolorization and pulp biobleaching. Furthermore, AAOs offer a huge potential as efficient suppliers of hydrogen peroxide for peroxidase- and peroxygenase-catalyzed reactions. A prerequisite for application as biocatalysts at larger scale is the production of AAOs in sufficient amounts. Heterologous expression of these predominantly fungal enzymes is, however, quite challenging. This review summarizes different approaches aiming at enhancing heterologous expression of AAOs and gives an update on substrates accepted by these promising enzymes as well as potential fields of their application. Key points • Aryl-alcohol oxidases (AAOs) supply ligninolytic peroxidases with H2O2. • AAOs accept a broad spectrum of aromatic and aliphatic allylic alcohols. • AAOs are potential biocatalysts for the production of high-value-added bio-based chemicals.

Characterization of a thermotolerant aryl-alcohol oxidase from Moesziomyces antarcticus oxidizing 5-hydroxymethyl-2-furancarboxylic acid

“…AAOs (EC 1.1.3.7) are FAD-dependent oxidoreductases that belong to the glucose-methanol-choline (GMC) oxidoreductase superfamily and play an essential role in biomass degradation as they supply peroxide-dependent ligninolytic enzymes with hydrogen peroxide. Although most AAOs described so far have been found in basidiomycetous and ascomycetous fungi, enzymes with AAO activity have been identified in bacteria, insects, and gastropods as well (Ferreira et al 2015 ; Serrano et al 2020 ; Urlacher and Koschorreck 2021 ). AAOs typically oxidize benzylic and polyunsaturated aliphatic primary alcohols to the corresponding aldehydes via hydrogen abstraction and transfer to molecular oxygen to produce hydrogen peroxide (Guillen et al 1992 ).…”

Biocatalytic Production of Aldehydes: Exploring the Potential of Lathyrus cicera Amine Oxidase

“…Aldehydes can be enzymatically synthesized by oxidation of the corresponding primary alcohols [20] and primary amines [21] or by reduction of the corresponding carboxylic acids [22][23][24]. Aldehyde synthesis starting from the corresponding alcohols can be performed by alcohol oxidases, which are typically active on a broad range of alcohols, such as primary and secondary alcohols, allylic and aryl alcohols, sterols, and carbohydrates [25,26]. However, the major drawback of these enzymes is the overoxidation of the aldehydes to carboxylic acids.…”

Trends and Applications of Omics Technologies to Functional Characterisation of Enzymes and Protein Metabolites Produced by Fungi

“…Aryl-alcohol oxidase Synthesis of high value-added chemicals, flavours, production of bio-based polymer precursors, dye decolourisation, pulp bleaching [50,51]…”