Investigation of protein allocation and utilization in the versatile chemolithoautotroph Cupriavidus necator

The aim of this study was to understand how autotrophic (CO2-fixing) bacteria balance the different needs for substrate assimilation, growth functions, and resilience in order to thrive in their environment.To this end, the proteome of the model chemolithoautotroph Ralstonia eutropha a.k.a. Cupriavidus necator was studied in different environmental conditions (four limiting substrates, and five different growth rates). Cupriavidus was cultivated in substrate-limited chemostats with fructose, formate, succinate and ammonium limitation to obtain steady state cell samples. The dilution rate/growth rate was increased step-wise from 0.05 to 0.25 1/h in 0.05 steps. Protein quantity was determined by LC-MS, and enzyme utilization was investigated by resource balance analysis modeling.