Activity of an Aspergillus terreus α-arabinofuranosidase on phenolic-substituted oligosaccharides

The effect of phenolic substitutions on the activity of an alpha-arabinofuranosidase from Aspergillus terreus was investigated using feruloylated oligosaccharides isolated from plant cell walls, equivalent oligosaccharides obtained through treatment with specific ferulic acid esterases: and a synthetic lignin-carbohydrate complex (LCC). Feruloyl substituents limited the hydrolysis of arabinoxylan and arabinan oligosaccharides but only if the feruloyl group was esterified to the terminal non-reducing arabinose. Somewhat surprisingly, the LCC-model compound, in which the arabinose residue is substituted with a bulky dilignol group, was degraded by the enzyme. This indicated that the enzyme is able to approach this linkage from the xylose side. (C) 1999 Elsevier Science B.V. All rights reserved.