Effect of Glucose Analog Supplementation on Metabolic Flux Distribution in Anaerobic Chemostat Cultures of Escherichia coli

Previous work in our laboratories investigated the use of methyl α-glucoside (α-MG), a glucose analog that shares a phosphotransferase system with glucose, to modulate glucose uptake and therefore reduce acetate accumulation. The results of that study showed a significant improvement in batch culture performance and a reduction in acetate excretion without any significant effect on the growth rate in complex medium. The current study investigates the effect of supplementing the culture medium with the glucose analog α-MG on the metabolic fluxes of Escherichia coli under anaerobic chemostat conditions at two different dilution rates. Anaerobic chemostat studies utilizing complex media supplemented with glucose or glucose and α-MG at dilution rates of 0.1 and 0.4 h−1, were performed, and the metabolic fluxes were analyzed. It was found that the addition of the glucose analog α-MG has an effect on the specific production rate of various extracellular metabolites. This effect is slightly greater at the higher dilution rate of 0.4 h−1. However, the glucose analog does not cause any major shift in the central metabolic patterns. It was further observed that α-MG supplementation does not result in the reduction in specific acetate synthesis rate in anaerobic chemostat cultures. These results emphasize the importance of testing different strategies for metabolic manipulation under the actual operating conditions.