Chongqing Institute of Green and Interligent Technology, Chinese Academy of Science. 266, Fangzheng Avenue, Shuitu High-tech Park, Beibei, Chongqing 400714, China.
Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, 400001, China.
Sci Rep. 2016 Dec 20;6:39543. doi: 10.1038/srep39543.
Biosynthesis approaches for the production of higher alcohols as a source of alternative fossil fuels have garnered increasing interest recently. However, there is little information available in the literature about using undirected whole-cell mutagenesis (UWCM) in vivo to improve higher alcohols production. In this study, for the first time, we approached this question from two aspects: first preferentially improving the capacity of expression host, and subsequently optimizing metabolic pathways using multiple genetic mutations to shift metabolic flux toward the biosynthetic pathway of target products to convert intermediate 2-keto acid compounds into diversified C4~C5 higher alcohols using UWCM in vivo, with the aim of improving the production. The results demonstrated the production of higher alcohols including isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol from glucose and duckweed under simultaneous saccharification and fermentation (SSF) scheme were higher based on the two aspects compared with only the use of wild-type stain as expression host. These findings showed that the improvement via UWCM in vivo in the two aspects for expression host and metabolic flux can facilitate the increase of higher alcohols production before using gene editing technology. Our work demonstrates that a multi-faceted approach for the engineering of novel synthetic pathways in microorganisms for improving biofuel production is feasible.
最近，作为替代化石燃料的来源，生产高级醇的生物合成方法引起了越来越多的关注。然而，文献中关于使用无定向全细胞诱变（UWCM）在体内提高高级醇产量的信息很少。在这项研究中，我们首次从两个方面探讨了这个问题：首先是优先提高表达宿主的能力，然后使用多种基因突变来优化代谢途径，将代谢通量转向目标产物的生物合成途径，以 UWCM 在体内将中间 2-酮酸化合物转化为多样化的 C4~C5 高级醇，从而提高产量。结果表明，与仅使用野生型菌株作为表达宿主相比，基于这两个方面，在同步糖化和发酵（SSF）方案下，从葡萄糖和浮萍中生产高级醇，包括异丁醇、2-甲基-1-丁醇和 3-甲基-1-丁醇的产量更高。这些发现表明，通过 UWCM 在体内对表达宿主和代谢通量进行改进，可以在使用基因编辑技术之前促进高级醇产量的增加。我们的工作表明，在微生物中设计新型合成途径以提高生物燃料产量的多方面方法是可行的。
