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- Title
- Homofermentative production of D- or L-lactate in metabolically engineered Escherichia coli RR1
- Author(s)
- Dong Eun Chang; Heung Chae Jung; Joon Shick Rhee; Jae Gu Pan
- Bibliographic Citation
- Applied and Environmental Microbiology, vol. 65, no. 4, pp. 1384-1389
- Publication Year
- 1999
- Abstract
- We investigated metabolic engineering of fermentation pathways in Escherichia coli for production of optically pure D- or L-lactate. Several pta mutant strains were examined, and a pta mutant of E. coli RR1 which was deficient in the phosphotransacetylase of the Pta-AckA pathway was found to metabolize glucose to D-lactate and to produce a small amount of succinate by-product under anaerobic conditions. An additional mutation in ppc made the mutant produce D-lactate like a homofermentative lactic acid bacterium. When the pta ppc double mutant was grown to higher biomass concentrations under aerobic conditions before it shifted to the anaerobic phase of D-lactate production, more than 62.2 g of D-lactate per liter was produced in 60 h, and the volumetric productivity was 1.04 g/liter/h. To examine whether the blocked acetate flux could be reoriented to a nonindigenous L-lactate pathway, an L-lactate dehydrogenase gene from Lactobacillus casei was introduced into a pta ldhA strain which lacked phosphotransacetylase and D- lactate dehydrogenase. This recombinant strain was able to metabolize glucose to L-lactate as the major fermentation product, and up to 45 g of L-lactate per liter was produced in 67 h. These results demonstrate that the central fermentation metabolism of E. coli can be reoriented to the production of D- lactate, an indigenous fermentation product, or to the production of L- lactate, a nonindigenous fermentation product.
- ISSN
- 0099-2240
- Publisher
- Amer Soc Microb
- DOI
- http://dx.doi.org/10.1128/aem.65.4.1384-1389.1999
- Type
- Article
- Appears in Collections:
- Division of Bio Technology Innovation > SME Support Center > 1. Journal Articles
- Files in This Item:
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