Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), Suwon, Republic of Korea.
Biotechnol Bioeng. 2018 Aug;115(8):2067-2074. doi: 10.1002/bit.26720. Epub 2018 May 8.
Combinatorial metabolic engineering enabled the development of efficient microbial cell factories for modulating gene expression to produce desired products. Here, we report the combinatorial metabolic engineering of Corynebacterium glutamicum to produce butyrate by introducing a synthetic butyrate pathway including phosphotransferase and butyrate kinase reactions and repressing the essential acn gene-encoding aconitase, which has been targeted for downregulation in a genome-scale model. An all-in-one clustered regularly interspaced short palindromic repeats interference system for C. glutamicum was used for tunable downregulation of acn in an engineered strain, where by-product-forming reactions were deleted and the synthetic butyrate pathway was inserted, resulting in butyrate production (0.52 ± 0.02 g/L). Subsequently, biotin limitation enabled the engineered strain to produce butyrate (0.58 ± 0.01 g/L) without acetate formation for the entire duration of the culture. These results demonstrate the potential homo-production of butyrate using engineered C. glutamicum. This method can also be applied to other industrial microorganisms.
组合代谢工程使构建高效微生物细胞工厂来调节基因表达以生产所需产物成为可能。在这里，我们报告了通过引入包括磷酸转移酶和丁酸激酶反应的合成丁酸途径以及抑制必需的 aconitase 基因（编码 aconitase）来对谷氨酸棒状杆菌进行组合代谢工程改造，该基因已被靶向用于在基因组规模模型中下调。使用用于谷氨酸棒状杆菌的一体式簇状规则间隔短回文重复干扰系统可对工程菌株中的 acn 进行可调下调，其中删除了副产物形成反应并插入了合成丁酸途径，从而产生丁酸（0.52±0.02 g/L）。随后，生物素限制使工程菌株能够在整个培养过程中生产丁酸（0.58 ± 0.01 g/L）而不形成乙酸盐。这些结果表明，使用工程化的谷氨酸棒状杆菌可以实现丁酸的同源生产。该方法也可应用于其他工业微生物。
