Butyrate re-assimilation in C. acetobutylicum re-evaluated using modeling

Version 1

This presentation reports about the results from an investigation of a ClosTron-mutant lacking CoA-transferase activity. Using our two-population model developed for the wild type of C. acetobutylicum, we analyse the changes in the formation of products caused by that mutation. In particular, we focus on the investigation of the acid re-assimilation after the initiation of the pH shift. Our comparison of experimental data and simulation unravels that an CoA-independent re-assimilation mechanism for butyrate, but not for acetate, exists in C. acetobutylicum. The analysis of the assimilation rate suggests that this mechanisms mainly contributes to the re-assimilation of butyrate in forward-shift experiments in phosphate-limited continuous cultures. This new results and our findings from the wild type challenge the textbook view of the CoA-transferase in Clostridium acetobutylicum.