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用于丙酮-丁醇-乙醇（ABE）发酵时，在酸水解过程中会产生几种对乙酰丁酸梭菌有毒的木质纤维素衍生抑制剂，严重阻碍了木质纤维素丁醇的工业化。在这项研究中，通过加强脯氨酸的生物合成，构建了对多种木质纤维素衍生的抑制剂（甲酸和酚类化合物）具有明显改善的耐受性的工程菌株824（proABC）。该工程菌株表现出更有效的脯氨酸合成能力和活性氧（ROS）清除能力。因此，由824（proABC当以大豆秸秆，稻草或玉米秸秆的未经过氧化处理的水解产物为底物时，）分别比野生型菌株高1、2.4或3.4倍。因此，增强脯氨酸的生物合成可用作提高丙酮丁醇梭菌对多种木质纤维素衍生抑制剂的耐受性的有效策略，并且824（proABC）具有由未经过氧化的木质纤维素水解产物生产丁醇的巨大潜力。