Glucuronoyl esterases are active on polymeric substrate, methyl esterified glucuronoxylan

Authors: BIELY, PETER - Slovak Academy Of Sciences; MALOVIKOVA, ANNA - Slovak Academy Of Sciences; UHLIARIKOVA, IVETA - Slovak Academy Of Sciences; LI, XIN-LIANG - Youtell Bio Chemical Incorporated; Wong, Dominic

Submitted to: FEBS Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2015
Publication Date: 7/26/2015
Citation: Biely, P., Malovikova, A., Uhliarikova, I., Li, X., Wong, D. 2015. Glucuronoyl esterases are active on polymeric substrate, methyl esterified glucuronoxylan. FEBS Letters. 589:2334-2339.

Interpretive Summary: Plant cell walls contain covalent crosslinkages between hemicellulose and lignin. These are ester bonds between 4-methyl-D-glucuronic acid and lignin alcohols. Glucuronic acid-mediated crosslinking is a major cause of the recalcitrance of biomass against enzymatic digestion. Our laboratory in collaboration with other groups has investigated the enzyme glucuronoyl esterase from several microorganisms that shows the potential function of breaking down lignin-carbohydrate complexes in plant cell walls. This is the first report to provide evidence that the enzyme recognizes and acts on methyl esterified glucuronoxylan as part of high molecular mass polysaccharide. The enzyme has potential applications in increasing the digestibility of lignocellulosic materials.

Technical Abstract: Alkali extracted beechwood glucuronoxylan methyl ester prepared by esterification of 4-O-methyl-D-glucuronic acid side residues by methanol was found to serve as substrate of microbial glucuronoyl esterases from Ruminococcus flavefaciens, Schizophyllum commune and Trichoderma reesei. The enzymatic deesterification was monitored by 1H-NMR spectroscopy and evaluated on the basis of the decrease of the signal of the ester methyl group and increase of the signal of methanol. The results show for the first time the action of enzymes on polymeric substrate which imitates more closely the natural substrate in plant cell walls than low molecular mass artificial substrates used up to the presence.