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Title: Escherichia coli aceE variants coding pyruvate dehydrogenase improve the generation of pyruvate‐derived acetoin
Abstract

Several chromosomally expressed AceE variants were constructed inEscherichia coli ΔldhA ΔpoxB ΔppsAand compared using glucose as the sole carbon source. These variants were examined in shake flask cultures for growth rate, pyruvate accumulation, and acetoin production via heterologous expression of thebudAandbudBgenes fromEnterobacter cloacae ssp. dissolvens. The best acetoin‐producing strains were subsequently studied in controlled batch culture at the one‐liter scale. PDH variant strains attained up to four‐fold greater acetoin than the strain expressing the wild‐type PDH. In a repeated batch process, the H106V PDH variant strain attained over 43 g/L of pyruvate‐derived products, acetoin (38.5 g/L) and 2R,3R‐butanediol (5.0 g/L), corresponding to an effective concentration of 59 g/L considering the dilution. The acetoin yield from glucose was 0.29 g/g with a volumetric productivity of 0.9 g/L·h (0.34 g/g and 1.0 g/L·h total products). The results demonstrate a new tool in pathway engineering, the modification of a key metabolic enzyme to improve the formation of a product via a kinetically slow, introduced pathway. Direct modification of the pathway enzyme offers an alternative to promoter engineering in cases where the promoter is involved in a complex regulatory network.

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NSF-PAR ID:
10399879
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Engineering in Life Sciences
Volume:
23
Issue:
3
ISSN:
1618-0240
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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