Characterization of a feruloyl esterase from Aspergillus terreus facilitates the division of fungal enzymes from Carbohydrate Esterase family 1 of the carbohydrate‐active enzymes (CAZy) database

Summary Feruloyl esterases ( FAE s) are accessory enzymes for plant biomass degradation, which catalyse hydrolysis of carboxylic ester linkages between hydroxycinnamic acids and plant cell‐wall carbohydrates. They are a diverse group of enzymes evolved from, e.g. acetyl xylan esterases ( AXE s), lipases and tannases, thus complicating their classification and prediction of function by sequence similarity. Recently, an increasing number of fungal FAE s have been biochemically characterized, owing to their potential in various biotechnological applications and multitude of candidate FAE s in fungal genomes. However, only part of the fungal FAE s are included in Carbohydrate Esterase family 1 ( CE 1) of the carbohydrate‐active enzymes ( CAZ y) database. In this work, we performed a phylogenetic analysis that divided the fungal members of CE 1 into five subfamilies of which three contained characterized enzymes with conserved activities. Conservation within one of the subfamilies was confirmed by characterization of an additional CE 1 enzyme from Aspergillus terreus . Recombinant A. terreus FaeD (AtFaeD) showed broad specificity towards synthetic methyl and ethyl esters, and released ferulic acid from plant biomass substrates, demonstrating its true FAE activity and interesting features as potential biocatalyst. The subfamily division of the fungal CE 1 members enables more efficient selection of candidate enzymes for biotechnological processes.