Engineering improved thermostability of the GH11 xylanase from Neocallimastix patriciarum via computational library design.

Xylanases， which cleave the β-1，4-glycosidic bond between xylose residues to release xylooligosaccharides (XOS)， are widely used as food additives， animal feeds， and pulp bleaching agents. However， the thermally unstable nature of xylanases would hamper their industrial application. In this study， we used in silico design in a glycoside hydrolase family (GH) 11 xylanase to stabilize the enzyme. A combination of the best mutations increased the apparent melting temperature by 14 °C and significantly enhanced thermostability and thermoactivation. The variant also showed an upward-shifted optimal temperature for catalysis without compromising its activity at low temperatures. Moreover， a 10-fold higher XOS production yield was obtained at 70 °C， which compensated the low yield obtained with the wild-type enzyme. Collectively， the variant constructed by the computational strategy can be used as an efficient biocatalyst for XOS production at industrially viable conditions.