FIG 1.

Pathway of anaerobic toluene degradation via benzylsuccinate. The left half shows the proposed pathway of facultative anaerobic bacteria and the right half shows that of strictly anaerobic bacteria, transferring the electrons from benzylsuccinyl-CoA oxidation to ubiquinone or menaquinone, respectively. BssABC, benzylsuccinate synthase; BbsEF, benzylsuccinate CoA-transferase; BbsG, benzylsuccinyl-CoA dehydrogenase; BbsH, enoyl-CoA hydratase; BbsCD, alcohol dehydrogenase; BbsAB, benzoylsuccinyl-CoA thiolase; ETF, electron transfer flavoprotein; ETF:Q OR, ETF-quinone oxidoreductase; ETF:MK OR, hypothetical ETF-menaquinone oxidoreductase.