Carbohydrate esterase family 16 contains fungal hemicellulose acetyl esterases (HAEs) with varying specificity

• Published in: New biotechnology 2022-09, Vol.70, p.28-38
• Main Authors: Venegas, Felipe Andrés, Koutaniemi, Sanna, Langeveld, Sandra M.J., Bellemare, Annie, Chong, Sun-Li, Dilokpimol, Adiphol, Lowden, Michael J., Hilden, Kristiina S., Leyva-Illades, Juan Francisco, Mäkelä, Miia R., My Pham, Thi Thanh, Peng, Mao, Hancock, Mark A., Zheng, Yun, Tsang, Adrian, Tenkanen, Maija, Powlowski, Justin, de Vries, Ronald P.
• Format: Article
• Language: English
• Subjects: Acetyl esterase; Aspergillus niger; biotechnology; CE16; esterases; fungi; Glucomannan; hemicellulose; oligosaccharides; phylogeny; phytomass; Substrate specificity; Xylan; Xyloglucan; xyloglucans
• ISSN: 1871-6784; 1876-4347
• DOI: 10.1016/j.nbt.2022.04.003

Acetyl esterases are an important component of the enzymatic machinery fungi use to degrade plant biomass and are classified in several Carbohydrate Esterase families of the CAZy classification system. Carbohydrate Esterase family 16 (CE16) is one of the more recently discovered CAZy families, but only a small number of its enzyme members have been characterized so far, revealing activity on xylan-derived oligosaccharides, as well as activity related to galactoglucomannan. The number of CE16 genes differs significantly in the genomes of filamentous fungi. In this study, four CE16 members were identified in the genome of Aspergillus niger NRRL3 and it was shown that they belong to three of the four phylogenetic Clades of CE16. Significant differences in expression profiles of the genes and substrate specificity of the enzymes were revealed, demonstrating the diversity within this family of enzymes. Detailed characterization of one of these four A. niger enzymes (HaeA) demonstrated activity on oligosaccharides obtained from acetylated glucuronoxylan, galactoglucomannan and xyloglucan, thus establishing this enzyme as a general hemicellulose acetyl esterase. Their broad substrate specificity makes these enzymes highly interesting for biotechnological applications in which deacetylation of polysaccharides is required. •Aspergillus niger possesses four CE16 genes with diverse sequences and expression patterns.•CE16 enzymes are hemicellulose acetyl esterases with diverse substrate specificity.•niger HaeA can remove acetyl from xylan, galactoglucomannan and xyloglucan.