Polysaccharide utilization loci-driven enzyme discovery reveals BD-FAE: a bifunctional feruloyl and acetyl xylan esterase active on complex natural xylans

Biotechnology for Biofuels

Nicolas Terrapon¹  Léa Jaillot¹  Lisanne Hameleers²  Edita Jurak²  Leena Penttinen³  Martina Ikonen³  Emma R. Master⁴  Peter J. Deuss⁵  Nina Hakulinen⁶  Régis Fauré⁷ 

[1] Architecture Et Fonction Des Macromolécules Biologiques (AFMB), UMR7257 Centre National de La Recherche Scientifique (CNRS) and Aix-Marseille Université (AMU), USC1408 Institut National de Recherche Pour L’Agriculture, l’Alimentation Et L’Environnement (INRAE), 13288, Marseille cedex 9, France;Department of Bioproduct Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands;Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland;Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland;Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, M5S 3E5, Toronto, ON, Canada;Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands;Department of Chemistry, University of Eastern Finland, Yliopistokatu 7, 80130, Joensuu, Finland;Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France;

关键词: Feruloyl esterase (FAE);    Acetyl xylan esterase (AcXE);    Carbohydrate esterase (CE);    Protein of unknown function (PUF);    Polysaccharide utilization loci (PULs);    Xylan;    Enzyme discovery;    Carbohydrate active enzymes (CAZymes);   

DOI  :  10.1186/s13068-021-01976-0

来源: Springer

【 摘 要 】

BackgroundNowadays there is a strong trend towards a circular economy using lignocellulosic biowaste for the production of biofuels and other bio-based products. The use of enzymes at several stages of the production process (e.g., saccharification) can offer a sustainable route due to avoidance of harsh chemicals and high temperatures. For novel enzyme discovery, physically linked gene clusters targeting carbohydrate degradation in bacteria, polysaccharide utilization loci (PULs), are recognized ‘treasure troves’ in the era of exponentially growing numbers of sequenced genomes.ResultsWe determined the biochemical properties and structure of a protein of unknown function (PUF) encoded within PULs of metagenomes from beaver droppings and moose rumen enriched on poplar hydrolysate. The corresponding novel bifunctional carbohydrate esterase (CE), now named BD-FAE, displayed feruloyl esterase (FAE) and acetyl esterase activity on simple, synthetic substrates. Whereas acetyl xylan esterase (AcXE) activity was detected on acetylated glucuronoxylan from birchwood, only FAE activity was observed on acetylated and feruloylated xylooligosaccharides from corn fiber. The genomic contexts of 200 homologs of BD-FAE revealed that the 33 closest homologs appear in PULs likely involved in xylan breakdown, while the more distant homologs were found either in alginate-targeting PULs or else outside PUL contexts. Although the BD-FAE structure adopts a typical α/β-hydrolase fold with a catalytic triad (Ser-Asp-His), it is distinct from other biochemically characterized CEs.ConclusionsThe bifunctional CE, BD-FAE, represents a new candidate for biomass processing given its capacity to remove ferulic acid and acetic acid from natural corn and birchwood xylan substrates, respectively. Its detailed biochemical characterization and solved crystal structure add to the toolbox of enzymes for biomass valorization as well as structural information to inform the classification of new CEs.

【 授权许可】

CC BY