Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China; School of Food and Chemical Engineering, Beijing Technology and Business University, No.11, Fucheng Road, Beijing 100048, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China; Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology and Business University, Beijing 100048, China.
Int J Biol Macromol. 2018 Dec;120(Pt A):405-413. doi: 10.1016/j.ijbiomac.2018.08.099. Epub 2018 Aug 23.
Highly efficient and stable enzymes are required for application in biotechnology, to meet the technical, environmental, and economic industrial demands. Xylanases are hemicellulolytic enzymes that degrade the heteroxylan constituent of the lignocellulosic plant cell wall. In this study, an acidic xylanase designated Pjxyn (pH 4.0) from Penicillium janthinellum was engineered by the introduction of a disulfide bridge. This strategy exploited the influence of the bridge on hydrolysis characteristics and enhanced hydrolysis was achieved. Three mutants [PjxynS(27)S(39), PjxynS(27)S(186), and PjxynS(39)S(186)] produced more xylose and xylobiose as hydrolysis products compared with the wild-type Pjxyn, when commercial xylans and lab-prepared water-insoluble corncob-xylan were used as the substrates, especial for the PjxynS(27)S(39) mutant, the content of xylose and xylobiose was 87.62% (using beechwood xylan) and 69.91% (using oat-spelt xylan) higher than that in the hydrolysis products of Pjxyn. Moreover, each mutant combined with the xylanase mutant T-XynFM effectively decreased the production of xylose with an optimum xylobiose yield. The findings demonstrate the potential industrial value of engineering xylanase to improve its hydrolytic properties and thermostability.
高效且稳定的酶是生物技术应用所必需的，以满足技术、环境和经济工业需求。木聚糖酶是半纤维素酶，可降解木质纤维素植物细胞壁中异木聚糖的成分。在这项研究中，通过引入二硫键对来自青霉（Penicillium janthinellum）的酸性木聚糖酶 Pjxyn（pH 4.0）进行了工程改造。该策略利用了桥对水解特性的影响，实现了水解增强。与野生型 Pjxyn 相比，三种突变体 [PjxynS(27)S(39)、PjxynS(27)S(186)和 PjxynS(39)S(186)] 在使用商业木聚糖和实验室制备的不溶性玉米芯木聚糖作为底物时，产生了更多的木糖和木二糖作为水解产物，特别是突变体 PjxynS(27)S(39)，其木糖和木二糖的含量分别比 Pjxyn 的水解产物高 87.62%（使用山毛榉木聚糖）和 69.91%（使用燕麦黑麦木聚糖）。此外，每种突变体与木聚糖酶突变体 T-XynFM 结合，有效地降低了木糖的产量，同时获得了最佳的木二糖产量。这些发现证明了工程改造木聚糖酶以提高其水解性能和热稳定性的潜在工业价值。
