Xylanase is widely used for the degradation lignocellulosic biomass as an important accessory enzyme. But productive hydrolysis of the recalcitrant lignocellulose also requires for applicable pretreatment with environmental friendliness. Meanwhile, the complicated industrial processes also demand for catalytically efficient enzymes with more resistance to both pH and heating conditions, which barely exist for the wild types. In this study, the dominant mutant H51K/Q118A from derived GtXyn10 (WT) was obtained by directed evolution. Compared to the WT, apart from the impressive pH resistance from pH 1.0–9.0, the dominant mutant H51K/Q118A also exhibited higher specific activity (2.5-fold; 2510 vs. 1010 U/mg), higher catalytic efficiency (2.4-fold; 460 vs. 190 mL/s‧mg), and better thermostability (with at 80 °C extend by 10 min). When ‘Seawater + Feton’ pretreatment was applied, the lignin clearance rate reached 62.5%, 86.6% higher than that of feton pretreatment (33.5%). After pretreatment of ‘Seawater + Feton’, Compared with the cellulase-only treatment (159 μmol/g), synergistic hydrolysis with both H51K/Q118A and cellulase (236 μmol/g) increased the fermentable sugar yields from bagasse by 48.4%. In combination with the optimized pretreatment and synergistic hydrolysis of the modified xylanase and cellulase, the fermentable sugar production for green bio-energy was realized with efficiency.

中文翻译：

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基于通道障碍消除策略提高GH10木聚糖酶活性，以更好地协同纤维素酶以增强绿色生物能源生产


木聚糖酶作为重要的辅助酶被广泛用于木质纤维素生物质的降解。但难降解木质纤维素的高效水解还需要适用且环境友好的预处理。同时，复杂的工业过程也需要具有更高催化效率的酶，这些酶对 pH 值和加热条件具有更强的抵抗力，而野生酶几乎不存在这种能力。在本研究中，通过定向进化获得了来自衍生GtXyn10（WT）的显性突变体H51K/Q118A。与WT相比，除了在pH 1.0-9.0范围内具有令人印象深刻的pH耐受性外，显性突变体H51K/Q118A还表现出更高的比活性（2.5倍；2510 vs. 1010 U/mg）、更高的催化效率（2.4倍；2.5倍；2510 vs. 1010 U/mg）。 460 vs. 190 mL/s‧mg)，以及更好的热稳定性（80 °C 延长 10 分钟）。采用“海水+Feton”预处理时，木质素清除率达到62.5%，比Feton预处理（33.5%）提高86.6%。经过“海水+ Feton”预处理后，与仅使用纤维素酶处理（159 μmol/g）相比，H51K/Q118A 和纤维素酶（236 μmol/g）协同水解使甘蔗渣的可发酵糖产量提高了 48.4%。结合改性木聚糖酶和纤维素酶的优化预处理和协同水解，实现了绿色生物能源发酵糖的高效生产。