BioChem - DOS

Optimization of hexanoic acid production in recombinant Escherichia coli by precise flux rebalancing

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Kim, Seong Gyeong; Jang, Sungho; Lim, Jae Hyung; Jeon, Byoung Seung; Kim, Jungyeon; Kim, Kyoung Heon; Sang, Byoung-In; Jung, Gyoo Yeol

<P><B>Abstract</B></P> <P>The aim of this study is to demonstrate that rebalancing of metabolic fluxes at acetyl-CoA branch node can substantially improve the titer and productivity of hexanoic acid in recombinant <I>Escherichia coli</I> strains. First, a hexanoic acid-producing <I>E. coli</I> strain was constructed by expressing genes encoding &beta;-ketothiolase (BktB) from <I>Cupriavidus necator</I> and acetyl-CoA transferase (ACT) from <I>Megasphaera</I> sp. MH in a butyric acid producer strain. Next, metabolic flux was optimized at the acetyl-CoA branch node by fine-tuning the expression level of the gene for acetyl-CoA acetyltransferase (AtoB). Four synthetic 5&prime;-untranslated regions were designed for <I>atoB</I> using UTR Designer to modulate the expression level of the gene. Notably, the productivity of the optimized strain (14.7 mg/L/h) was the highest among recombinant <I>E. coli</I> strains in literature when using a similar inoculum size for fermentation. These results show that fine-tuning the expression level of <I>atoB</I> is critical for production of hexanoic acid.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Recombinant <I>E. coli</I> strains were constructed to produce hexanoic acid. </LI> <LI> The enzyme that catalyzes the last step of the hexanoic acid pathway was replaced. </LI> <LI> Precise flux rebalancing at the acetyl-CoA branch point was achieved. </LI> <LI> The productivity achieved was 8.7-fold higher than that in the parental strain. </LI> <LI> The productivity of the optimized strain was 14.7 mg/L/h. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2018

Elsevier

0960-8524

247

pp.1253-1257

10.1016/j.biortech.2017.10.014

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART79612549

Hexanoic acid; Flux rebalancing; Acetyl-CoA acetyltransferase; 5′-UTR; Acetyl-CoA transferase