The pH-induced metabolic shift from acidogenesis to solventogenesis in Clostridium acetobutylicum - From experiments to models

Version 1

This presentation given at the 5th International Beilstein Symposium presents the development of a model for the pH-induced shift in C. acetobutylicum. Starting from experimental information, the model construction and underlying assumptions are explained. Furthermore, the required additions to the metabolic and genetic network caused by the used experimentals setup are established.

The established metabolic and genetic model is compared to dynamic shift experiments starting at acidogenesis and solventogenesis. We show that this phase transition of C. acetobutylicum is associated to a cellular adaptation of the proteome. However, the dynamics during those transition is reproduced insufficiently.

The external pH is crucial for the behaviour of C. acetobutylicum, hence implications to the pH-dependent product spectrum of branch points in the ABE fermentation pathway are discussed. The comparison between simulations and experimental data reveals that further information about the pH-dependent kinetic regulation of the pathway are required for an improvement of the model.