Anaerobic oxidation of short-chain and cyclic alkanes by sulfate-reducing bacteria

Evidence from marine oil and gas seepages recently indicated that anaerobic biodegradation of non-methane hydrocarbons may be an important process influencing the cycling of carbon and sulfur. To date, only little is known about the microorganisms able to degrade C2 C4 n-alkanes and cycloalkanes under anaerobic conditions and the involved activation mechanisms. In this study, new propane and n-butane degrading, sulfate-reducing enrichment cultures were obtained from sediments of cold marine hydrocarbon seeps and further investigated with regard to the phylotypes involved in the anaerobic degradation of propane and n-butane, their physiology and the involved activation mechanisms. Furthermore, an extremely slow growing, sulfate-reducing and ethane degrading enrichment culture from a marine cold hydrocarbon seep was investigated with regard to phylogenetic composition. A sulfate-reducing, cyclohexane degrading enrichment culture was obtained from hydrocarbon contaminated intertidal sediment and investigated with regard to the dominant phylotype, the involved activation mechanism and the spectrum of degradable hydrocarbon substrates.