Xylanase and protease increase solubilization of non-starch polysaccharides and nutrient release of corn- and wheat distillers dried grains with solubles

• Xylanases are capable of releasing pentosan and protein from corn- and wheat DDGS.
• Wheat DDGS is more easily degradable than corn DDGS.
• GH10 xylanase is more efficient in degrading corn DDGS than GH11xylanase.
• Protease increase release of both pentosan and protein.

The use of distiller dried grains with solubles (DDGS) as alternative to conventional animal feed for non-ruminants is challenged by the high content of non-starch polysaccharides and varying protein quality. In this study the enzymatic degradation of corn- and wheat DDGS was evaluated, in vitro, by use of four xylanases from two different glycoside hydrolase families, GH10 and GH11, along with protease and phytase. Wheat DDGS showed the highest degree of enzymatic degradation due to a lower degree of cell wall complexity compared with that of corn DDGS. For corn DDGS,the combination of xylanase and protease yielded the highest degree of enzymatic degradation, indicating close association of arabinoxylan and protein within the cell wall matrix. Collectively, the GH10xylanase degraded DDGS more efficiently than the GH11 xylanases, due to the complexity of the DDGS substrate and the substrate affinity of the GH10xylanase. The current in vitro results indicate a high potential of xylanase in combination with protease to efficiently degrade DDGS and promote nutrient release in diets for non-ruminant animals.

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