title: Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.
abstract: Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unknown hydrocarbon-degrading anaerobic microorganisms, discovery of novel reactions, detailed studies of enzyme mechanisms and structures to process-oriented in situ studies. Selected highlights from this program are collected in this synopsis, with more detailed information provided by theme-focused reviews of the special topic issue on 'Anaerobic biodegradation of hydrocarbons' [this issue, pp. 1-244]. The interdisciplinary character of the program, involving microbiologists, biochemists, organic chemists and environmental scientists, is best exemplified by the studies on alkyl-/arylalkylsuccinate synthases. Here, research topics ranged from in-depth mechanistic studies of archetypical toluene-activating benzylsuccinate synthase, substrate-specific phylogenetic clustering of alkyl-/arylalkylsuccinate synthases (toluene plus xylenes, p-cymene, p-cresol, 2-methylnaphthalene, n-alkanes), stereochemical and co-metabolic insights into n-alkane-activating (methylalkyl)succinate synthases to the discovery of bacterial groups previously unknown to possess alkyl-/arylalkylsuccinate synthases by means of functional gene markers and in situ field studies enabled by state-of-the-art stable isotope probing and fractionation approaches. Other topics are Mo-cofactor-dependent dehydrogenases performing O2-independent hydroxylation of hydrocarbons and alkyl side chains (ethylbenzene, p-cymene, cholesterol, n-hexadecane), degradation of p-alkylated benzoates and toluenes, glycyl radical-bearing 4-hydroxyphenylacetate decarboxylase, novel types of carboxylation reactions (for acetophenone, acetone, and potentially also benzene and naphthalene), W-cofactor-containing enzymes for reductive dearomatization of benzoyl-CoA (class II benzoyl-CoA reductase) in obligate anaerobes and addition of water to acetylene, fermentative formation of cyclohexanecarboxylate from benzoate, and methanogenic degradation of hydrocarbons.
authors.affiliation: General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Rabus
authors.forename: Matthias
authors.initials: M
authors.lastname: Boll
authors.forename: Johann
authors.initials: J
authors.lastname: Heider
authors.forename: Rainer U
authors.initials: RU
authors.lastname: Meckenstock
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Buckel
authors.forename: Oliver
authors.initials: O
authors.lastname: Einsle
authors.forename: Ulrich
authors.initials: U
authors.lastname: Ermler
authors.forename: Bernard T
authors.initials: BT
authors.lastname: Golding
authors.forename: Robert P
authors.initials: RP
authors.lastname: Gunsalus
authors.forename: Peter M H
authors.initials: PM
authors.lastname: Kroneck
authors.forename: Martin
authors.initials: M
authors.lastname: Krüger
authors.forename: Tillmann
authors.initials: T
authors.lastname: Lueders
authors.forename: Berta M
authors.initials: BM
authors.lastname: Martins
authors.forename: Florin
authors.initials: F
authors.lastname: Musat
authors.forename: Hans H
authors.initials: HH
authors.lastname: Richnow
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schink
authors.forename: Jana
authors.initials: J
authors.lastname: Seifert
authors.forename: Maciej
authors.initials: M
authors.lastname: Szaleniec
authors.forename: Tina
authors.initials: T
authors.lastname: Treude
authors.forename: G Matthias
authors.initials: GM
authors.lastname: Ullmann
authors.forename: Carsten
authors.initials: C
authors.lastname: Vogt
authors.forename: Martin
authors.initials: M
authors.lastname: von Bergen
authors.forename: Heinz
authors.initials: H
authors.lastname: Wilkes
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D044822:Biodiversity; D006838:Hydrocarbons / Q000378:metabolism*; D010802:Phylogeny
chemical_list: D006838:Hydrocarbons