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Published on: December 15, 2017
An efficient succinic acid production process in a metabolically engineered Corynebacterium glutamicum strain
Shohei Okino1, Ryoji Noburyu, Masako Suda
1Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa, Kyoto, 619-0292, Japan.
Applied Microbiology and Biotechnology
|September 9, 2008
Summary
This study engineered Corynebacterium glutamicum for efficient succinic acid production, achieving high concentrations and yields under oxygen-deprived conditions with controlled bicarbonate addition.
Area of Science:
- Biotechnology
- Metabolic Engineering
- Industrial Microbiology
Background:
- Succinic acid is a valuable platform chemical with diverse industrial applications.
- Optimizing microbial strains and fermentation processes is crucial for cost-effective succinic acid production.
- Genetic modification of Corynebacterium glutamicum offers a promising route for enhanced succinate biosynthesis.
Purpose of the Study:
- To investigate the succinic acid production capabilities of a metabolically engineered Corynebacterium glutamicum strain.
- To optimize fermentation conditions, including oxygen availability and nutrient supplementation, for maximizing succinic acid yield.
- To elucidate the role of pyruvate carboxylase and L-lactate dehydrogenase in succinic acid synthesis pathways.
Main Methods:
- Genetic engineering of Corynebacterium glutamicum by overexpressing the pyruvate carboxylase (pyc) gene and disrupting the L-lactate dehydrogenase (ldhA) gene.
- High-cell-density fermentation under oxygen-deprived conditions with intermittent feeding of glucose and sodium bicarbonate.
- Monitoring of succinic acid and acetic acid concentrations, yields, and production rates throughout the fermentation process.
Main Results:
- The engineered strain (DeltaldhA-pCRA717) achieved a high succinic acid concentration of 1.24 M (146 g/l) within 46 hours.
- Succinic acid yields reached 1.40 mol/mol (0.92 g/g) from glucose, with a byproduct acetic acid yield of 0.29 mol/mol (0.10 g/g).
- Succinic acid production and yield were found to be dependent on bicarbonate concentration, indicating its direct role in biosynthesis.
Conclusions:
- The engineered Corynebacterium glutamicum strain demonstrates high efficiency in succinic acid production.
- Intermittent bicarbonate addition under oxygen deprivation is a key factor for optimizing succinic acid fermentation.
- This metabolic engineering strategy provides a robust platform for industrial-scale succinic acid manufacturing.
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