从 sp. T7 中鉴定和表征一种新型内切-β-1,4-木聚糖酶及其在木寡糖生产中的应用。

Identification and Characterization of a Novel Endo-β-1,4-Xylanase from sp. T7 and Its Application in Xylo-Oligosaccharide Production.

机构信息

Department of Biological Science and Biotechnology, University of Jinan, Jinan 250022, China.

出版信息

Molecules. 2022 Apr 13;27(8):2516. doi: 10.3390/molecules27082516.

A xylanase-producing strain, identified as sp. T7, was isolated from soil by our lab. The endo-β-1,4-xylanase (ST7) gene was found in the genome sequence of strain T7, which was cloned and expressed in . XynST7 belonged to the glycoside hydrolase family 10, with a molecular mass of approximately 47 kDa. The optimum pH and temperature of XynST7 were pH 6.0 and 60 °C, respectively, and it showed wide pH and temperature adaptability and stability, retaining more than half of its enzyme activity between pH 5.0 and 11.0 below 80 °C. XynST7 showed only endo-β-1,4-xylanase activity without cellulase- or β-xylosidase activity, and it showed maximal hydrolysis for corncob xylan in all the test substrates. Then, XynST7 was used for the production of xylo-oligosaccharides (XOSs) by hydrolyzing xylan extracted from raw corncobs. The maximum yield of the XOS was 8.61 ± 0.13 mg/mL using 15 U/mL of XynST7 and 1.5% corncob xylan after 10 h of incubation at 60 °C. The resulting hydrolysate products mainly consisted of xylobiose and xylotriose. These data indicated that XynST7 might by a promising tool for various industrial applications.

一株木聚糖酶产生菌，被鉴定为 sp. T7，是我们实验室从土壤中分离得到的。内切-β-1,4-木聚糖酶（ST7）基因存在于 T7 菌株的基因组序列中，该基因被克隆并在中表达。XynST7 属于糖苷水解酶家族 10，分子量约为 47 kDa。XynST7 的最适 pH 和温度分别为 pH 6.0 和 60°C，它具有较宽的 pH 和温度适应性和稳定性，在 pH 5.0 至 11.0 之间、低于 80°C 时，仍保留超过一半的酶活性。XynST7 仅具有内切-β-1,4-木聚糖酶活性，而没有纤维素酶或β-木糖苷酶活性，在所有测试底物中，它对玉米芯木聚糖的水解活性最高。然后，XynST7 被用于通过水解从生玉米芯中提取的木聚糖来生产木二糖（XOS）。在 60°C 下孵育 10 小时，使用 15 U/mL 的 XynST7 和 1.5%玉米芯木聚糖，XOS 的最大产量为 8.61±0.13 mg/mL。所得水解产物主要由木二糖和木三糖组成。这些数据表明，XynST7 可能是各种工业应用的有前途的工具。