Abstract:
A. succinogenes is well known for utilising various catabolic pathways. A multitude of
batch fermentation studies confirm flux shifts in the catabolism as time proceeds. It has also been
shown that continuous cultures exhibit flux variation as a function of dilution rate. This indicates
a direct influence of the external environment on the proteome of the organism. In this work, ATP
production efficiency was explored to evaluate the extent of bio-available energy on the production
behaviour of A. succinogenes. It was found that the microbe successively utilised its most-to-least
efficient energy extraction pathways, providing evidence of an energy optimisation survival strategy.
Moreover, data from this study suggest a pyruvate overflow mechanism as a means to throttle acetic
and formic acid production, indicating a scenario in which the external concentration of these acids
play a role in the energy extraction capabilities of the organism. Data also indicates a fleeting regime
where A. succinogenes utilises an oxidised environment to its advantage for ATP production. Here it is
postulated that the energy gain and excretion cost of catabolites coupled to the changing environment
is a likely mechanism responsible for the proteome alteration and its ensuing carbon flux variation.
This offers valuable insights into the microbe’s metabolic logic gates, providing a foundation to
understand how to exploit the system.
