Acetate is a beneficial nutrient for E. coli at low glycolytic flux

Abstract

Acetate, a major by‐product of glycolytic metabolism in Escherichia coli and many other microorganisms, has long been considered a toxic waste compound that inhibits microbial growth. This counterproductive auto‐inhibition represents a major problem in biotechnology and has puzzled the scientific community for decades. Recent studies have however revealed that acetate is also a co‐substrate of glycolytic nutrients and a global regulator of E. coli metabolism and physiology. Here, we used a systems biology strategy to investigate the mutual regulation of glycolytic and acetate metabolism in E. coli. Computational and experimental analyses demonstrate that decreasing the glycolytic flux enhances co‐utilization of acetate with glucose. Acetate metabolism thus compensates for the reduction in glycolytic flux and eventually buffers carbon uptake so that acetate, rather than being toxic, actually enhances E. coli growth under these conditions. We validated this mechanism using three orthogonal strategies: chemical inhibition of glucose uptake, glycolytic mutant strains, and alternative substrates with a natively low glycolytic flux. In summary, acetate makes E. coli more robust to glycolytic perturbations and is a valuable nutrient, with a beneficial effect on microbial growth.

Integrativein vivoanalysis of the ethanolamine utilization bacterial microcompartment inEscherichia coli.

“…Some of the EA-derived C then enters central metabolism, mainly through the TCA cycle, to fuel growth. This result is in line with a recent report demonstrating that E. coli assimilates acetate (here derived from ethanolamine) with glycolytic substrates when the glycolytic flux is low, such as on glycerol 59 , to feed anabolism. But why then is E. coli K-12 W3110 WT unable to grow with EA as sole C source?…”

ATP biosensor reveals microbial energetic dynamics and facilitates bioproduction

“…Traditionally, acetate has been viewed as a less favorable carbon source, often associated with overflow metabolism. Nevertheless, recent studies have begun to recognize the beneficial role of acetate in facilitating robust growth during glycolytic perturbation 1 , 28 . Our ATP dynamics results corroborate that acetate promotes cellular ATP concentrations, suggesting its potential to enhance the biosynthesis of energy-demanding products.…”

PhysioFit: a software to quantify cell growth parameters and extracellular fluxes

“…Quantification of microbial growth rates and extracellular uptake and production fluxes is an essential task to address fundamental and applied questions in the fields of systems and synthetic biology, biotechnology, and health (Millard et al, 2023;Peiro et al, 2019;Hui et al, 2020).…”