Carbon limitation-specific physiology
Relief from CCR
In G. metallireducens, the anaerobic degradation of acetate and benzoate proceeds through distinct peripheral catabolic pathways that might lead to sequential utilization of these substrates. As already shown , benzoate gives higher biomass yield per mol of substrate consumed and could be of primary interest for the organism. However, in an accompanying paper , we have shown that acetate is preferred over benzoate during growth under carbon excess. In contrast, at low growth rates in retentostats, G. metallireducens was able to co-utilize acetate and benzoate. Simultaneous consumption of aromatic compounds and easily degradable substrates (e.g. acetate) in carbon-limited chemostats has also been reported for the aerobic microorganism Ralstonia pickettii PKO1 [4] and Pseudomonas sp. Therefore, in carbon-limited natural environments with traces of aromatic contaminants, microorganisms may generally use several substrates
simultaneously