title: Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons.
abstract: Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers.
authors.affiliation: Universitx00E4;t Duisburg-Essen, Biofilm Centre, Essen, Germany.
authors.forename: Rainer U
authors.initials: RU
authors.lastname: Meckenstock
authors.forename: Matthias
authors.initials: M
authors.lastname: Boll
authors.forename: Housna
authors.initials: H
authors.lastname: Mouttaki
authors.forename: Janina S
authors.initials: JS
authors.lastname: Koelschbach
authors.forename: Paola
authors.initials: P
authors.lastname: Cunha Tarouco
authors.forename: Philip
authors.initials: P
authors.lastname: Weyrauch
authors.forename: Xiyang
authors.initials: X
authors.lastname: Dong
authors.forename: Anne M
authors.initials: AM
authors.lastname: Himmelberg
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D001554:Benzene / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D053858:Metabolic Networks and Pathways; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D001554:Benzene