Herein, we cloned and expressed an endo-β-1,4-glucanase gene (celA1805) from Bacillus subtilis B111 in Escherichia coli. The recombinant celA1805 contains a glycosyl hydrolase (GH) family 8 domain and shared 76.8% homology with endo-1,4-β-glucanase from Bacillus sp. KSM-330. Results showed that the optimal pH and temperature of celA1805 were 6.0 and 50^◦C, respectively, and it was stable at pH 3-9 and temperature ≤50°C. Metal ions slightly effected enzyme activity, but chemical agents generally inhibited enzyme activity. Moreover, celA1805 showed a wide substrate specificity to CMC, barley β-Glucan, lichenin, chitosan, PASC and Avcel. The K_m and V_max values of celA1805 were 1.78 mg/mL and 50.09μmol/min/mg. When incubated with cellooligosaccharides ranging from cellotriose to cellopentose, celA1805 mainly hydrolyzed cellotetrose (G4) and cellopentose (G5) to cellose (G2) and cellotriose (G3), but hardly hydrolyzed cellotriose. The concentration of reducing sugars saccharified by celA1805 from wheat straw, rape straw, rice straw, peanut straw, and corn straw were increased by 0.21, 0.51, 0.26, 0.36, and 0.66 mg/mL, respectively. The results obtained in this study suggest potential applications of celA1805 in biomass saccharification.

中文翻译：

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来自枯草芽孢杆菌 B111 的 GH8 β-1,4-葡聚糖酶的表征及其对农业秸秆的糖化潜力。

在此，我们在大肠杆菌中克隆并表达了来自枯草芽孢杆菌B111的内切-β-1,4-葡聚糖酶基因 ( celA1805 ) 。重组 celA1805 包含一个糖基水解酶 (GH) 家族 8 结构域，与来自芽孢杆菌的内切 1,4-β-葡聚糖酶具有 76.8% 的同源性。KSM-330。结果表明，celA1805 的最适 pH 和温度分别为 6.0 和 50 ^° C，并且在 pH 3-9 和温度≤50°C 时稳定。金属离子对酶的活性影响较小，而化学试剂一般对酶的活性有抑制作用。此外，celA1805 对 CMC、大麦 β-葡聚糖、地衣素、壳聚糖、PASC 和 Avcel 表现出广泛的底物特异性。K _m和V __{celA1805 的最大值}为 1.78 mg/mL 和 50.09μmol/min/mg。当与从纤维三糖到纤维五糖的纤维寡糖一起孵育时，celA1805 主要将纤维三糖 (G4) 和纤维五糖 (G5) 水解为纤维糖 (G2) 和纤维三糖 (G3)，但几乎不水解纤维三糖。celA1805糖化小麦秸秆、油菜秸秆、水稻秸秆、花生秸秆和玉米秸秆的还原糖浓度分别提高了0.21、0.51、0.26、0.36和0.66 mg/mL。本研究中获得的结果表明 celA1805 在生物质糖化中的潜在应用。