Systems metabolic engineering of Corynebacterium glutamicum for the production of the carbon-5 platform chemicals 5-aminovalerate and glutarate.
BACKGROUND
The steadily growing world population and our ever luxurious life style, along with the simultaneously decreasing fossil resources has confronted modern society with the issue and need of finding renewable routes to accommodate for our demands. Shifting the production pipeline from raw oil to biomass requires efficient processes for numerous platform chemicals being produced with high yield, high titer and high productivity.


RESULTS
In the present work, we established a de novo bio-based production process for the two carbon-5 platform chemicals 5-aminovalerate and glutarate on basis of the lysine-hyperproducing strain Corynebacterium glutamicum LYS-12. Upon heterologous implementation of the Pseudomonas putida genes davA, encoding 5-aminovaleramidase and davB, encoding lysine monooxygenase, 5-aminovalerate production was established. Related to the presence of endogenous genes coding for 5-aminovalerate transaminase (gabT) and glutarate semialdehyde dehydrogenase, 5-aminovalerate was partially converted to glutarate. Moreover, residual L-lysine was secreted as by-product. The issue of by-product formation was then addressed by deletion of the lysE gene, encoding the L-lysine exporter. Additionally, a putative gabT gene was deleted to enhance 5-aminovalerate production. To fully exploit the performance of the optimized strain, fed-batch fermentation was carried out producing 28 g L(-1) 5-aminovalerate with a maximal space-time yield of 0.9 g L(-1) h(-1).


CONCLUSIONS
The present study describes the construction of a recombinant microbial cell factory for the production of carbon-5 platform chemicals. Beyond a basic proof-of-concept, we were able to specifically increase the production flux of 5-aminovalerate thereby generating a strain with excellent production performance. Additional improvement can be expected by removal of remaining by-product formation and bottlenecks, associated to the terminal pathway, to generate a strain being applicable as centerpiece for a bio-based production of 5-aminovalerate.
Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
Christina Maria
CM
Rohles
Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
Gideon
G
Gießelmann
Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
Michael
M
Kohlstedt
Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
Christoph
C
Wittmann
Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany. judith.becker@uni-saarland.de.
Judith
J
Becker
D000581:Amidohydrolases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D026923:Amino Acid Transport Systems, Basic / Q000172:deficiency / Q000235:genetics; D021542:Amino Acids, Neutral / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics; D002244:Carbon / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D005977:Glutarates / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D016958:Pseudomonas putida / Q000201:enzymology / Q000235:genetics; D058615:Synthetic Biology / Q000379:methods; D049490:Systems Biology / Q000379:methods
D026923:Amino Acid Transport Systems, Basic; D021542:Amino Acids, Neutral; D001426:Bacterial Proteins; D005977:Glutarates; C104616:LysE protein, Corynebacterium glutamicum; C013809:5-aminovaleric acid; D002244:Carbon; D006899:Mixed Function Oxygenases; C100031:lysine monooxygenase; D000581:Amidohydrolases; C019694:5-aminovaleramidase; D008239:Lysine
Bio-economy; Bio-nylon; Heterologous production; Lysine monooxygenase; Metabolic engineering; Platform chemical; Synthetic biology