School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China.
School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China.
Bioresour Technol. 2019 Jan;272:561-569. doi: 10.1016/j.biortech.2018.10.038. Epub 2018 Oct 17.
When lignocellulosic biomass was used for acetone-butanol-ethanol (ABE) fermentation, several lignocellulose-derived inhibitors, which are toxic to Clostridium acetobutylicum, were generated during acid hydrolysis process and seriously hindered the industrialization of lignocellulosic butanol. In this study, an engineered strain 824(proABC) with significantly improved tolerance to multiple lignocellulose-derived inhibitors (formic acid and phenolic compounds) was constructed by strengthening the proline biosynthesis. The engineered strain exhibited more effective synthesis ability of proline and scavenging ability of reactive oxygen species (ROS). Consequently, the butanol produced by 824(proABC) was 1-, 2.4- or 3.4-fold higher than that of the wild type strain when using the undetoxified hydrolysate of soybean straw, rice straw or corn straw as the substrate, respectively. Therefore, enhancing the proline biosynthesis can be used as an effective strategy to improve the tolerance of C. acetobutylicum to multiple lignocellulose-derived inhibitors, and 824(proABC) has great potential to produce butanol from undetoxified lignocellulosic hydrolysates.
当木质纤维素生物质被用于丙酮丁醇乙醇（ABE）发酵时，在酸水解过程中会产生几种木质纤维素衍生的抑制剂，这些抑制剂对丙酮丁醇梭菌有毒，严重阻碍了木质纤维素丁醇的工业化进程。在本研究中，通过强化脯氨酸生物合成，构建了一株对多种木质纤维素衍生抑制剂（甲酸和酚类化合物）具有显著耐受性的工程菌株 824（proABC）。该工程菌株表现出更高的脯氨酸合成能力和活性氧（ROS）清除能力。因此，当使用未经解毒的大豆秸秆、水稻秸秆或玉米秸秆水解物作为底物时，824（proABC）生产的丁醇分别比野生型菌株高出 1、2.4 或 3.4 倍。因此，增强脯氨酸生物合成可以作为提高丙酮丁醇梭菌对多种木质纤维素衍生抑制剂耐受性的有效策略，824（proABC）具有从未经解毒的木质纤维素水解物中生产丁醇的巨大潜力。
