Integrative modelling of pH-dependent enzyme activity and transcriptomic regulation of the acetone-butanol-ethanol fermentation of Clostridium acetobutylicum in continuous culture

SysMO is a European transnational funding and research initiative on "Systems Biology of Microorganisms".

The goal pursued by SysMO was to record and describe the dynamic molecular processes going on in unicellular microorganisms in a comprehensive way and to present these processes in the form of computerized mathematical models.

Systems biology will raise biomedical and biotechnological research to a new quality level and contribute markedly to progress in understanding. Pooling European research ...

Systems Biology of Clostridium acetobutylicum - a possible answer to dwindling crude oil reserves

Monitoring of end products ethanol, acetone, butanol, acetate and butyrate during master fermentation of Clostridium acetobutylicum at the steady state pH values 5.5, 5.3, 5.1, 4.9 and 4.7.

Micro array analysis of steady-state growing cells of Clostridium acetobutylicum at pH 5.7 (acidogenesis) in comparison to pH 4.5 (solventogenesis).

Micro array analyses of all mRNA levels of cells growing at steady state pH values 5.7, 5.5, 5.3, 5.1, 4.9, 4.7 compared to the same reference steady-state pH 4.5.

All spots and identified proteins of Clostridium acetobutylicum growing at steady-state pH 5.7 (acidogenesis) and pH 4.5 (solventogenesis), respectively, using 2D PAGE and Maldi-TOF analysis. The focus were cytosolic proteins with an isoelectric point bewteen 4 and 7 as well as a molecular weight of 180-10 kDa.

Representation of all prepared 2D PAGE analyses of cytosolic proteins of Clostridium acetobutylicum growing continuously at pH 5.5, 5.3, 5.1, 4.9 and 4.7.

Here, we use hyperbolic tangents to fit experimental data of AB fermentation in C. acetobutylicum in continous culture at steady state for different external pHs. The estimated parameters are used to define acidogenic and solventogenic phase. Furthermore, an transition phase is identified which cannot be assigned to acidogenesis or solventogenesis.

Several plots compare the fits to the experimental data.