High-efficiency conversion of glycerol to D-lactic acid with metabolically engineered Escherichia coli

Escherichia coli strain CICIM B0013 was genetically engineered to efficiently produce optically pure D-lactate (higher than 99.9%) from glycerol with a minimum of by-products. When E. coli B0013-070 ( Delta ackA, Delta pta, Delta pps, Delta pflB, Delta dld, Delta poxB, Delta adhE, Delta frdA) was cu...

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Bibliographic Details
Published in:African journal of biotechnology 2012-03, Vol.11 (21), p.4860-4867
Main Authors: Tian, K, Chen, X, Shen, W, Prior, BA, Shi, G, Singh, S, Wang, Z
Format: Article
Language:English
Subjects:
Escherichia coli
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Summary:Escherichia coli strain CICIM B0013 was genetically engineered to efficiently produce optically pure D-lactate (higher than 99.9%) from glycerol with a minimum of by-products. When E. coli B0013-070 ( Delta ackA, Delta pta, Delta pps, Delta pflB, Delta dld, Delta poxB, Delta adhE, Delta frdA) was cultivated aerobically for 9 h followed by 27 h under microaerobic fermentation, it produced 98.5 g l super(-1) of D-lactate with no more than 2 g l super(-1) total by-products from glycerol. During the microaerobic phase, the average D-lactate productivity and yield were 3.45 g l super(-1) h super(-1) and 64 g/100 g glycerol, respectively. Elevated expression of the lactate dehydrogenase gene (ldhA) in strain B0013-070 improved conversion of glycerol to D-lactate resulting in a yield and productivity of 78 g/100 g glycerol and 3.65 g l super(-1) h super(-1), respectively. The metabolically engineered E. coli strain B0013-070 (pTH-ldhA) efficiently converted glycerol to D-lactate with a 2.1-fold higher D-lactate productivity than previously reported. It is concluded that overexpression of ldhA at an appropriate level is important for the balance between cell growth and D-lactate synthesis. Furthermore, biodiesel-based glycerol can be an appropriate substrate for industrial scale D-lactate production.
ISSN:1684-5315
1684-5315
DOI:10.5897/AJB11.3464