In this study, the proteome of the anaerobic iron-reducing,aromatic hydrocarbon-degrading Geobacter metallireducens was profiled at low growth rates in order to examine how different carbon sources would be utilized under conditions close to a natural state, which is important for understanding their role and function during the remediation of contaminated sites . Under these conditions, G. metallireducens was expected to enter into an energy-saving mode that would prevent the bacterium from full de-repression of catabolic pathways in contrast to E. coli cultivatedin chemostats .