Escherichia coli can survive on glucose and water alone
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CONTESTED
contested - evenly split
refutedsupported
the weight of evidence
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While some studies show Escherichia coli can utilize glucose as a sole carbon source in minimal media, other research indicates that glucose addition alone in natural lake water environments does not significantly enhance survival time.
Abstract 2′-Fucosyllactose (2′-FL) is the most abundant human milk oligosaccharide (HMO), playing vital roles in promoting infant gut health, enhancing immunity, and defending against pathogens. However, conventional 2′-FL biosynthesis typically relies on exogenous supplementation of lactose or fucose precursors, leading to high costs and process complexity. In this study, we report a streamlined de novo biosynthesis process for 2′-FL using glucose as the sole carbon source, achieved through systematic engineering of endogenous precursor pathways in Escherichia coli . First, the complete biosynthetic route from glucose to lactose and then to 2′-FL was reconstructed in a chassis strain capable of producing fucose. Unlike previous studies that primarily focused on the GDP-fucose supply module, this work systematically balanced the metabolic flux between phosphorylated and non-phosphorylated glucose pools to coordinate the supply of precursors for both lactose and GDP-fucose synthesis. This balance was achieved by reconstructing the glucose uptake system, modulating the expression of key enzymes at critical metabolic nodes, and eliminating competing pathways. Subsequently, the endogenous lactose synthesis pathway was further enhanced through coordinated overexpression of pgm , galU , and galE , and the pentose phosphate pathway and purine salvage pathway were optimized to enhance the supply of NADPH and GTP. Using this strategy, an engineered E. coli strain for efficient 2′-FL production was successfully constructed. The engineered strain produced 7.11 g/L 2′-FL in shake-flask fermentation and achieved a titer of 43.2 g/L in a 3-L bioreactor after 58 h, representing the highest reported yield for de novo 2′-FL synthesis from glucose as the sole carbon source. This work provides a promising and simplified strategy for the cost-effective industrial production of 2′-FL.
The effects of nutrients on the survival of Escherichia coli in lake water.
Escherichia coli was shown to survive without decline in viable counts for at least 12 d in filtered-autoclaved lake water. In unfiltered lake water there was a rapid decline in the viable count of E. coli. The addition of synthetic sewage to filtered-autoclaved lake water led to an increase in the viable count of E. coli at 15 degrees C and 37 degrees C and to an increase in the survival time of the E. coli in unfiltered water. The addition of phosphate and carbon sources (glucose, glycerol, succinate, acetate and lactose) did not significantly increase the survival time of E. coli in unfiltered water over the controls. The addition of ammonium sulphate and some amino acids (as nitrogen sources) to the unfiltered lake water did lead to an increase in the survival times for E. coli and this increase was proportional to the concentration of the added nitrogen source.
Published in The Journal of applied bacteriology (1989)
Escherichia coli was shown to survive without decline in viable counts for at least 12 d in filtered‐autoclaved lake water. In unfiltered lake water there was a rapid decline in the viable count of E. coli. The addition of synthetic sewage to filtered‐autoclaved lake water led to an increase in the viable count of E. coli at 15°C and 37°C and to an increase in the survival time of the E. coli in unfiltered water. The addition of phosphate and carbon sources (glucose, glycerol, succinate, acetate and lactose) did not significantly increase the survival time of E. coli in unfiltered water over the controls. The addition of ammonium sulphate and some amino acids (as nitrogen sources) to the unfiltered lake water did lead to an increase in the survival times for E. coli and this increase was proportional to the concentration of the added nitrogen source.
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