Breath! Respiring microbes generate more energy

In Denmark, researchers at the Novo Nordisk Foundation Center for Biosustainability (DTU Biosustain) at the Technical University of Denmark shed light on how bacteria and baker’s yeast generate and use their energy to grow and how it is possible to evoke a shift in the metabolism from fermentation to respiration of E. coli and baker’s yeast by optimising fermentation conditions. This shift means that the cells can be pushed into producing more internal energy (ATP). Knowing about cells’ energy use is essential for industrial biotech processes.

Using a computational approach, the researchers found out that high-energy molecules called ATP can be generated by either of two pathways: a high-yielding respiratory pathway resulting in 23.5 ATP’s per glucose molecule or a low-yielding fermentative pathway, which only generates 11 ATP’s per glucose molecule.

The two pathways supplement each other, but the researchers were able to shift the natural balance between the two by changing the conditions of the fermentation and the amount of sugar and protein available. Furthermore, they showed that the high-yielding pathway needs more protein mass than the low-yielding pathway for consuming glucose at the same rate.