College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.
Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi, China.
Biotechnol Prog. 2019 May;35(3):e2795. doi: 10.1002/btpr.2795. Epub 2019 Mar 9.
The high production cost of cellulase is one of the limitations that hinder the commercialization of lignocellulose-based biorefineries. As one of the important cellulases, Neurospora crassa cellulase is not so intensively investigated as T. reesei cellulase. In this study, the cbh1gene (NCU07340) cloned from N. crassa was expressed in Pichia pastoris under the control of alcohol oxidase 1 (AOX1) promotor. Six transformants with the highest resistance to G418 were selected by two rounds of transformant screening, among which the most robust producer of the recombinant cellobiohydrolase I (CBHI) has an Avicelase activity of 0.22 U/mL. After fermentation optimization, it was improved to 0.30 U/mL. Interestingly, the optimal temperature and pH of the recombinant CBHI were 60°C and 7.2, respectively, and it was quite stable within the wide ranges of temperature and pH. This work is a good example for the future improvement and optimization of N. crassa cellulase.
纤维素酶的高生产成本是限制木质纤维素基生物炼制厂商业化的因素之一。作为重要的纤维素酶之一，粗糙脉孢菌纤维素酶的研究不如里氏木霉纤维素酶那样深入。在这项研究中，从粗糙脉孢菌中克隆的 cbh1 基因（NCU07340）在毕赤酵母中受醇氧化酶 1（AOX1）启动子的控制下表达。通过两轮转化子筛选，选择了对 G418 具有最高抗性的 6 个转化子，其中重组纤维二糖水解酶 I（CBHI）产量最高的产毒株的 Avicelase 活性为 0.22 U/mL。经过发酵优化，它提高到 0.30 U/mL。有趣的是，重组 CBHI 的最适温度和 pH 值分别为 60°C 和 7.2，在较宽的温度和 pH 值范围内相当稳定。这项工作为未来粗糙脉孢菌纤维素酶的改进和优化提供了一个很好的范例。
