Jing Li, Yanghao Hu, Jun Wang, Zha Ziqian, Shuai You, Zhong-Li Chen, Wen-Xin Zhang, Zhi-Yuan Bai, Yiwen Chen, Huiying Luo, and Xue Wang
Background Xylanase, an important accessory enzyme that acts in synergy with cellulase, is widely used to degrade lignocellulosic biomass. Thermostable enzymes with good catalytic activity at lower temperatures have great potential for future applications in the feed and fuel industries, which have distinct demands; however, the potential of the enzymes is yet to be researched. Results In this study, a structure-based semi-rational design strategy was applied to enhance the low-temperature catalytic performance of Bispora sp. MEY-1 XYL10C_∆N wild-type (WT). Screening and comparisons were performed for the WT and mutant strains. Compared to the WT, the mutant M53S/F54L/N207G exhibited higher specific activity (2.9-fold; 2090 vs. 710 U/mg) and catalytic efficiency (2.8-fold; 1530 vs. 550 mL/s mg) at 40 °C, and also showed higher thermostability (the melting temperature and temperature of 50% activity loss after 30 min treatment increased by 7.7 °C and 3.5 °C, respectively). Compared with the cellulase-only treatment, combined treatment with M53S/F54L/N207G and cellulase increased the reducing sugar contents from corn stalk, wheat bran, and corn cob by 1.6-, 1.2-, and 1.4-folds, with 1.9, 1.2, and 1.6 as the highest degrees of synergy, respectively. Conclusions This study provides useful insights into the underlying mechanism and methods of xylanase modification for industrial utilization. We identified loop2 as a key functional area affecting the low-temperature catalytic efficiency of GH10 xylanase. The thermostable mutant M53S/F54L/N207G was selected for the highest low-temperature catalytic efficiency and reducing sugar yield in synergy with cellulase in the degradation of different types of lignocellulosic biomass. Graphic Abstract Supplementary Information The online version contains supplementary material available at 10.1186/s13068-021-02044-3., Highlights Key sites were proved to promote low-temperature catalytic efficiency of xylanase.Thermostable mutant with improved catalytic efficiency at 40 °C was obtained.Synergistic hydrolysis was dramatically improved between the mutant and cellulase.Agricultural wastes were converted into fermentable sugars by enzymolysis. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-021-02044-3.