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Regulation of NAD(H) pool and NADH/NAD+ ratio by overexpression of nicotinic acid phosphoribosyltransferase for succinic acid production in Escherichia coli NZN111

Paper ID Volume ID Publish Year Pages File Format Full-Text
17219 42652 2012 8 PDF Available
Title
Regulation of NAD(H) pool and NADH/NAD+ ratio by overexpression of nicotinic acid phosphoribosyltransferase for succinic acid production in Escherichia coli NZN111
Abstract

Succinic acid is not the dominant fermentation product from glucose in wild-type Escherichia coli W1485. To reduce byproduct formation and increase succinic acid accumulation, pyruvate formate-lyase and lactate dehydrogenase, encoded by pflB and ldhA genes, were inactivated. However, E. coli NZN111, the ldhA and pflB deletion strain, could not utilize glucose anaerobically due to the block of NAD+ regeneration. To restore glucose utilization, overexpression of nicotinic acid phosphoribosyltransferase, a rate limiting enzyme of NAD(H) synthesis encoded by the pncB gene, resulted in a significant increase in cell mass and succinic acid production. Furthermore, the results indicated a significant increase in NAD(H) pool size, and decrease in the NADH/NAD+ ratio from 0.64 to 0.13, in particular, the concentration of NAD+ increased 6.2-fold during anaerobic fermentation. In other words, the supply of enough NAD+ for NADH oxidation by regulation of NAD(H) salvage synthesis mechanism could improve the cell growth and glucose utilization anaerobically. In addition, the low NADH/NAD+ ratio also change the metabolite distribution during the dual-phase fermentation. As a result, there was a significant increase in succinic acid production, and it is provided further evidence that regulation of NAD(H) pool and NADH/NAD+ ratio was very important for succinic acid production.

► We constructed a recombinant strain designated as E. coli NZN111/pTrc99a-pncB. ► The specific enzyme activity of NAPRTase in NZN111/pTrc99a-pncB was increased. ► Regulation of NAD(H) pool and NADH/NAD+ ratio restored glucose utilization. ► Overexpression of NAPRTase increased the yield and productivity of succinic acid.

Keywords
E. coli NZN111; NAD(H); NADH/NAD+; Nicotinic acid phosphoribosyltransferase; Succinic acid
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Regulation of NAD(H) pool and NADH/NAD+ ratio by overexpression of nicotinic acid phosphoribosyltransferase for succinic acid production in Escherichia coli NZN111
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 51, Issue 5, 10 October 2012, Pages 286–293
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us