Trichoderma longibrachiatum acetyl xylan esterase 1 enhances hemicellulolytic preparations to degrade corn silage polysaccharides

• T. longibrachiatum preparation was fractionated and supplemented to an enzyme mixture.
• Synergistic potential was found by supplementation of acetyl xylan esterase 1 (Axe1).
• Deacetylation efficiency by Axe1 is demonstrated and compared to AxeA (A. niger).
• Acetic acid release by Axe1 was up to six times higher on model oligosaccharides.
• MS demonstrated efficient deacetylation of O-acetyl-(4-O-methylglucurono)xylan.

Supplementation of a Trichoderma longibrachiatum preparation to an industrial Aspergillus niger/Talaromyces emersonii enzyme mixture demonstrated synergy for the saccharification of corn silage water-unextractable solids (WUS). Sub-fractions of the crude T. longibrachiatum preparation obtained after chromatography were analyzed regarding their hydrolytic activity. An acetyl xylan esterase 1 [Axe1, carbohydrate esterase (CE) family 5]-enriched sub-fraction closely mimicked the hydrolytic gain as obtained by supplementation of the complete, crude enzyme mixture (increase of 50%, 62% and 29% for Xyl, Ara and Glc, respectively). The acetic acid released from model polysaccharides (WUS) and oligosaccharides [neutral (AcXOS) and acidic (AcUXOS) xylo-oligosaccharides] by Axe1 was two and up to six times higher compared to the acetic acid released by acetyl xylan esterase A (AxeA, CE 1). Characterization of Axe1 treated AcXOS and AcUXOS revealed deacetylation of oligosaccharides that were not deacetylated by AxeA or the A. niger/T. emersonii preparation.

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