Selective Enzymatic Release and Gel Formation by Cross-Linking of Feruloylated Glucurono-Arabinoxylan from Corn Bran

• DOI: 10.1021/acssuschemeng.0c00663
• Publication Date: 2020-05-11T18:48:49Z
• Authors: Line Munk; Jan Muschiol; Kai Li; Ming Liu; Alixander Perzon; Sebastian Meier; Peter Ulvskov; Anne S. Meyer
• Keywords: Arabinoxylan; Enzymatic Hydrolysis

Corn bran is a major agro-industrial byproduct from corn starch processing. The particularly rich in highly substituted feruloylated glucuronoarabinoxylan (FGAX). Yet, due to its recalcitrance biocatalytic degradation, FGAX currently not utilized biorefinery processes. Here, we report selective enzymatic extraction of both single- and double-stranded high-molecular-weight molecules using bacterial, glucuronoyl-specific glycoside hydrolase family 30 endo-1,4-β-xylanase (EC 3.2.1.8) Dickeya chrysanthemi (DcXyn30). DcXyn30 was optimized with respect temperature, pH, time maximize yields polysaccharides. Examination the enzymatically extracted SEC, HPAEC, LC-MS, NMR analyses (after acid or alkaline hydrolysis) revealed that single-stranded were extracted, since diferulate-linkages present FGAX. Furthermore, analysis indicated presence 1,5-linked arabinan dimers suggesting some xylopyranosyl residues contained arabinofuranosyl−arabinofuranosyl substitutions addition significant amount classical disubstituted xylosyls α-(1→2)- α-(1→3)-linked arabinosyl residues. Laccase treatment produced strong hydrogels via oxidative, covalent feruloyl-cross-linking. At pH 6.5, Myceliophthora thermophila derived laccase significantly faster cross-linking kinetics than Pleurotus ostreatus as measured rheologically. data reveal novel insight into chemistry provide new direction for enzyme-assisted upgrading valuable functional hydrogel applications.