Identification of Copper-Containing Oxidoreductases in the Secretomes of Three <i>Colletotrichum</i> Species with a Focus on Copper Radical Oxidases for the Biocatalytic Production of Fatty Aldehydes
David Ribeaucourt, Safwan Saker, David Navarro, Bastien Bissaro, Élodie Drula, Lydie Oliveira Correia, Mireille Haon, Sacha Grisel, Nicolas Lapalu, Bernard Henrissat, Richard J. O’Connell, Fanny Lambert, Mickaël Lafond, Jean‐Guy Berrin
Abstract
In the context of the industrial shift toward greener processes, the biocatalytic production of aldehydes is of utmost interest owing to their importance for their use as flavor and fragrance ingredients. Copper radical alcohol oxidases (CRO-AlcOx) have the potential to become platform enzymes for the oxidation of alcohols to aldehydes. However, the secretion of CRO-AlcOx by natural fungal strains has never been explored, while the use of crude fungal secretomes is an appealing approach for industrial applications to alleviate various costs pertaining to biocatalyst production. While investigating this primary objective, the secretomics studies revealed unexpected results showing that under the oxidative stress conditions we probed, Colletotrichum species can secrete a broad diversity of copper-containing enzymes (laccases, sugar oxidoreductases, and lytic polysaccharide monooxygenases [LPMOs]) usually assigned to "plant cell wall degradation," despite the absence of any plant-biomass mimicking compound. However, in these conditions, only small amounts of CRO-AlcOx were secreted, pointing out recombinant expression as the most promising path for their biocatalytic application.