Chen Xi, Yuan Youguo, 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.
Appl Biochem Biotechnol. 2025 May 15. doi: 10.1007/s12010-025-05254-9.
Recombinant Bacillus subtilis is currently used as a producer for riboflavin biosynthesis. In this study, a novel metabolic engineering strategy for the enhancement of purine salvage pathway in B. subtilis effectively improved the riboflavin biosynthesis by increasing the supply of precursors via an energy-saving route. Mutant strains overexpressing the related genes of salvage pathway exhibited higher production compared to the original strain. Specifically, the deoD-hprT co-overexpressing mutant BR-08 demonstrated a significant increase in riboflavin production, from 1049.84 to 1252.34 mg/L, representing a 19.29% improvement. To further amplify the impact of the salvage pathway, xylose was introduced into the fermentation process as an inducer to upregulate the expression of the relevant genes, while guanosine was added as a direct precursor. Following the optimization of the fermentation conditions, the riboflavin titer of mutant BR-08 reached 1898.58 mg/L. These findings substantiate the efficacy of the purine salvage pathway in enhancing riboflavin biosynthesis and offer a novel strategy for improving biosynthetic efficiency through an energy-conserving mechanism.
重组枯草芽孢杆菌目前被用作核黄素生物合成的生产菌株。在本研究中，一种用于增强枯草芽孢杆菌中嘌呤补救途径的新型代谢工程策略，通过节能途径增加前体供应，有效提高了核黄素的生物合成。与原始菌株相比，过表达补救途径相关基因的突变菌株表现出更高的产量。具体而言，共过表达deoD-hprT的突变体BR-08的核黄素产量显著增加，从1049.84毫克/升提高到1252.34毫克/升，提高了19.29%。为了进一步扩大补救途径的影响，将木糖作为诱导剂引入发酵过程以上调相关基因的表达，同时添加鸟苷作为直接前体。在优化发酵条件后，突变体BR-08的核黄素效价达到1898.58毫克/升。这些发现证实了嘌呤补救途径在增强核黄素生物合成中的功效，并提供了一种通过节能机制提高生物合成效率的新策略。
