Zhang Mengxue, Zhao Xingcong, Chen Xi, Li Mingyue, Wang Xuedong
State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.
College of Biological Science, University of California, Davis, USA.
Biotechnol Lett. 2021 Dec;43(12):2209-2216. doi: 10.1007/s10529-021-03190-2. Epub 2021 Oct 4.
The production of riboflavin with Bacillus subtilis, is an established process, however it is yet to be fully optimized. The aim of this study was to explore how riboflavin yields can be improved via in vitro and in vivo metabolic engineering modification of the pentose phosphate pathway (PPP).
In vitro, glucose was replaced with sodium gluconate to enhance PPP. Flask tests showed that the riboflavin titer increased from 0.64 to 0.87 g/L. The results revealed that the direct use of sodium gluconate could benefit riboflavin production. In vivo, gntP (encoding gluconate permease) was overexpressed to improve sodium gluconate uptake. The riboflavin titer reached 1.00 g/L with the mutant B. subtilis RF01. Ultimately, the fermentation verification of the engineered strain was carried out in a 7-L fermenter, with the increased riboflavin titer validating this approach.
The combination of metabolic engineering modifications in vitro and in vivo was confirmed to promote riboflavin production efficiently by increasing PPP and has great potential for industrial application. This work is aimed to explore how to improve the riboflavin yield by the rational renovation of the pentose phosphate pathway (PPP). In vitro, metabolic engineering mainly uses sodium gluconate as a carbon source instead of glucose, and in vivo, metabolic engineering mainly includes the overexpression of sodium gluconate utility-related genes. The effect of sodium gluconate on cell growth, riboflavin production was investigated in the flasks and fermenter scale.
利用枯草芽孢杆菌生产核黄素是一个既定的过程，但尚未得到充分优化。本研究的目的是探索如何通过对磷酸戊糖途径（PPP）进行体外和体内代谢工程改造来提高核黄素产量。
在体外，用葡萄糖酸钠替代葡萄糖以增强PPP。摇瓶试验表明，核黄素产量从0.64克/升提高到0.87克/升。结果表明，直接使用葡萄糖酸钠有利于核黄素生产。在体内，过表达gntP（编码葡萄糖酸盐通透酶）以改善葡萄糖酸钠的摄取。突变型枯草芽孢杆菌RF01的核黄素产量达到1.00克/升。最终，在7升发酵罐中对工程菌株进行发酵验证，核黄素产量的提高证实了这种方法。
体外和体内代谢工程改造相结合，通过增加PPP被证实可有效促进核黄素生产，具有很大的工业应用潜力。这项工作旨在探索如何通过合理改造磷酸戊糖途径（PPP）来提高核黄素产量。在体外，代谢工程主要使用葡萄糖酸钠作为碳源替代葡萄糖，在体内，代谢工程主要包括过表达与葡萄糖酸钠利用相关的基因。在摇瓶和发酵罐规模上研究了葡萄糖酸钠对细胞生长、核黄素生产的影响。
