Department of Chemical and Biological Engineering, Korea University, Sungbuk-Gu, Seoul 136-713, South Korea.
Biotechnol Bioeng. 2013 Oct;110(10):2790-4. doi: 10.1002/bit.24925. Epub 2013 Apr 22.
Butyrate pathway was constructed in recombinant Escherichia coli using the genes from Clostridium acetobutylicum and Treponema denticola. However, the pathway constructed from exogenous enzymes did not efficiently convert carbon flux to butyrate. Three steps of the productivity enhancement were attempted in this study. First, pathway engineering to delete metabolic pathways to by-products successfully improved the butyrate production. Second, synthetic scaffold protein that spatially co-localizes enzymes was introduced to improve the efficiency of the heterologous pathway enzymes, resulting in threefold improvement in butyrate production. Finally, further optimizations of inducer concentrations and pH adjustment were tried. The final titer of butyrate was 4.3 and 7.2 g/L under batch and fed-batch cultivation, respectively. This study demonstrated the importance of synthetic scaffold protein as a useful tool for optimization of heterologous butyrate pathway in E. coli.
丁酸途径是使用来自丙酮丁醇梭菌和密螺旋体的基因在重组大肠杆菌中构建的。然而，由外源酶构建的途径并不能有效地将碳通量转化为丁酸。本研究尝试了提高生产力的三个步骤。首先，通过途径工程删除代谢途径到副产物，成功地提高了丁酸的产量。其次，引入了空间上使酶共定位的合成支架蛋白，以提高异源途径酶的效率，使丁酸的产量提高了三倍。最后，尝试了进一步优化诱导剂浓度和 pH 值调整。在分批和补料分批培养下，丁酸的最终浓度分别为 4.3 和 7.2 g/L。本研究表明了合成支架蛋白作为优化大肠杆菌中异源丁酸途径的有用工具的重要性。
