College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, PR China; Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, PR China.
College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, PR China; Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, PR China.
Bioresour Technol. 2024 Nov;411:131345. doi: 10.1016/j.biortech.2024.131345. Epub 2024 Aug 23.
Orotic acid is widely used in healthcare and cosmetic industries. However, orotic acid-producing microorganisms are auxotrophic, which results in inefficient microbial production. Herein, a plasmid-free, uninduced, non-auxotrophic orotic acid hyperproducer was constructed from Escherichia coli W3110. Initially, the orotic acid degradation pathway was blocked and the carbamoyl phosphate supply was enriched. Subsequently, pyr operon from Bacillus subtilis F126 was heterologously expressed and precursors' supply was optimized. Thereafter, pyrE was dynamically regulated to reconstruct the non-auxotrophic pathway. Employing fed-batch cultivation, orotic acid titer, yield, and productivity of strain Ora21 reached 182.5 g/L, 0.58 g/g, and 3.80 g/L/h, respectively, the highest levels reported so far. Finally, a novel "Chaos to Order Cycles (COC)" fermentation was developed, which effectively increased the yield to 0.63 g/g. This research is a remarkable achievement in orotic acid production by microbial fermentation and has vast potential for industrial applications.
乳清酸在医疗保健和化妆品行业中被广泛应用。然而，生产乳清酸的微生物是营养缺陷型的，这导致微生物生产效率低下。在此，我们构建了一株来自大肠杆菌 W3110 的无质粒、非诱导、非营养缺陷型乳清酸高产菌。首先，阻断乳清酸降解途径并富集氨甲酰磷酸供应。然后，异源表达枯草芽孢杆菌 F126 的 pyr 操纵子并优化前体供应。此后，动态调节 pyrE 以重建非营养缺陷型途径。采用分批补料发酵，菌株 Ora21 的乳清酸浓度、产率和生产强度分别达到 182.5 g/L、0.58 g/g 和 3.80 g/L/h，均达到目前报道的最高水平。最后，开发了一种新型的“混沌到有序循环（COC）”发酵策略，有效地将产率提高到 0.63 g/g。本研究在微生物发酵生产乳清酸方面取得了显著进展，具有广阔的工业应用前景。
