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Gong Y, Wang R, Ma L, Wang S, Li C, Xu Q. Optimization of trans-4-hydroxyproline synthesis pathway by rearrangement center carbon metabolism in Escherichia coli. Microb Cell Fact 2023; 22:240. [PMID: 37986164 PMCID: PMC10659092 DOI: 10.1186/s12934-023-02236-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/22/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND trans-4-Hydroxyproline (T-4-HYP) is a promising intermediate in the synthesis of antibiotic drugs. However, its industrial production remains challenging due to the low production efficiency of T-4-HYP. This study focused on designing the key nodes of anabolic pathway to enhance carbon flux and minimize carbon loss, thereby maximizing the production potential of microbial cell factories. RESULTS First, a basic strain, HYP-1, was developed by releasing feedback inhibitors and expressing heterologous genes for the production of trans-4-hydroxyproline. Subsequently, the biosynthetic pathway was strengthened while branching pathways were disrupted, resulting in increased metabolic flow of α-ketoglutarate in the Tricarboxylic acid cycle. The introduction of the NOG (non-oxidative glycolysis) pathway rearranged the central carbon metabolism, redirecting glucose towards acetyl-CoA. Furthermore, the supply of NADPH was enhanced to improve the acid production capacity of the strain. Finally, the fermentation process of T-4-HYP was optimized using a continuous feeding method. The rate of sugar supplementation controlled the dissolved oxygen concentrations during fermentation, and Fe2+ was continuously fed to supplement the reduced iron for hydroxylation. These modifications ensured an effective supply of proline hydroxylase cofactors (O2 and Fe2+), enabling efficient production of T-4-HYP in the microbial cell factory system. The strain HYP-10 produced 89.4 g/L of T-4-HYP in a 5 L fermenter, with a total yield of 0.34 g/g, the highest values reported by microbial fermentation, the yield increased by 63.1% compared with the highest existing reported yield. CONCLUSION This study presents a strategy for establishing a microbial cell factory capable of producing T-4-HYP at high levels, making it suitable for large-scale industrial production. Additionally, this study provides valuable insights into regulating synthesis of other compounds with α-ketoglutaric acid as precursor.
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Affiliation(s)
- Yu Gong
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Ruiqi Wang
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Ling Ma
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Shuo Wang
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Changgeng Li
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Qingyang Xu
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China.
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China.
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