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Increased lysine production by flux coupling of the tricarboxylic acid cycle and the lysine biosynthetic pathway—Metabolic engineering of the availability of succinyl-CoA in Corynebacterium glutamicum

Paper ID Volume ID Publish Year Pages File Format Full-Text
31662 44827 2013 12 PDF Available
Title
Increased lysine production by flux coupling of the tricarboxylic acid cycle and the lysine biosynthetic pathway—Metabolic engineering of the availability of succinyl-CoA in Corynebacterium glutamicum
Abstract

In this study, we demonstrate increased lysine production by flux coupling using the industrial work horse bacterium Corynebacterium glutamicum, which was mediated by the targeted interruption of the tricarboxylic acid (TCA) cycle at the level of succinyl-CoA synthetase. The succinylase branch of the lysine production pathway functions as the bridging reaction to convert succinyl-CoA to succinate in this aerobic bacterium. The mutant C. glutamicum ΔsucCD showed a 60% increase in the yield of lysine when compared to the advanced lysine producer which was used as parent strain. This mutant was highly vital and exhibited only a slightly reduced specific growth rate. Metabolic flux analysis with 13C isotope studies confirmed that the increase in lysine production was mediated by pathway coupling. The novel strain exhibited an exceptional flux profile, which was closer to the optimum performance predicted by in silico pathway analysis than to the large set of lysine-producing strains analyzed thus far. Fluxomics and transcriptomics were applied as further targets for next-level strain engineering to identify the back-up mechanisms that were activated upon deletion of the enzyme in the mutant strain. It seemed likely that the cells partly recruited the glyoxylate shunt as a by-pass route. Additionally, the α-ketoglutarate decarboxylase pathway emerged as the potential compensation mechanism. This novel strategy appears equally promising for Escherichia coli, which is used in the industrial production of lysine, wherein this bacterium synthesizes lysine exclusively by succinyl-CoA activation of pathway intermediates. The channeling of a high flux pathway into a production pathway by pathway coupling is an interesting metabolic engineering strategy that can be explored to optimize bio-production in the future.

► Superior lysine producing Corynebacterium glutamicum strain. ► Metabolic engineering through coupling of TCA cycle and biosynthetic pathway fluxes. ► Succinyl-CoA availability limits lysine over-production. ► Deletion of succinyl-CoA synthetase increases lysine yield by 60%.

Keywords
Succinylase pathway; Succinyl-CoA synthetase; 13C metabolic flux; Lysine; TCA cycle; Glyoxylate shunt; Systems metabolic engineering; Escherichia coli
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Increased lysine production by flux coupling of the tricarboxylic acid cycle and the lysine biosynthetic pathway—Metabolic engineering of the availability of succinyl-CoA in Corynebacterium glutamicum
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 15, January 2013, Pages 184–195
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