College of Animal Sciences and Technology, Northwest A&F University, 712100, Yangling, People's Republic of China.
Mol Biol Rep. 2010 Oct;37(7):3297-302. doi: 10.1007/s11033-009-9915-6. Epub 2009 Dec 1.
An alkaline active xylanase, XynBYG, was purified from an alkaliphilic Bacillus pumilus BYG, which was newly isolated from paper mill effluent. It had an optimum pH of 8.0-9.0, and showed good stability after incubated at pH 9.0 for 120 min. The optimum temperature for the activity was 50°C, and the enzyme retained below 55% of its original activity for 30 min at 55°C. The gene coding for XynBYG consists of 687 bp and encodes 229 amino acids. Similarity analysis indicated that XynBYG belong to family 11 glycosyl hydrolases. Site-directed mutagenesis was performed to replace five sites (Tyr/Ser) to Arg/Glu and the results demonstrated that the optimum temperature of the mutant Y7 (S39R-T146E) increased 5°C and the half-life of inactivation (T1/2) at 60 and 65°C was 1 h and 25 min, respectively. Thus, it provides a potential xylanase that can meet the harsh conditions in the industrial applications.
一株嗜碱芽孢杆菌（Bacillus pumilus BYG）新分离得到的碱性木聚糖酶 XynBYG 的分离纯化及其性质研究 从造纸厂废水分离到一株嗜碱芽孢杆菌（Bacillus pumilus BYG），该菌能产生碱性木聚糖酶 XynBYG。XynBYG 的最适 pH 为 8.0-9.0，在 pH9.0 下孵育 120min 后仍保持较高的相对酶活。最适反应温度为 50°C，在 55°C 下保温 30min 后酶活保留 55%。XynBYG 基因全长 687bp，编码 229 个氨基酸。序列同源性分析表明，XynBYG 属于糖苷水解酶 11 家族。对其进行定点突变，将其中 5 个 Tyr/Ser 突变为 Arg/Glu，突变酶 Y7（S39R-T146E）的最适反应温度提高了 5°C，60°C 和 65°C 时的半衰期（T1/2）分别为 1h 和 25min。因此，该酶具有一定的工业应用潜力。
