Organohalides has been and are still used for a wide range of industrial applications. Unfortunately are many of these toxic to humans and other animals. The release of these compounds into the environment are therefore considered as an environmental problem. These compounds are often difficult to degrade and can therefore stay in the environment for long time. Some bacteria are able to degrade these, under oxygen free conditions. We have studied bacteria belonging to two different genera belonging to the phylum Firmicutes. These are Dehalobacter and Desulfitobacterium, representing two contrasting lifestyles. The former does only grow on organohalides, whereas the latter has been shown to grow on organohalides and a wide range of other substrates. We analysed and compared the genomes and proteome of representative of these two genera to obtain an improved understanding of how these bacteria have degrades these compounds, which ultimately may lead to more efficient and cheaper methods for cleaning polluted soil and groundwater.