人們對在海洋滲出氣體中生活的生物,、尤其是依靠甲烷生存的微生物的興趣日趨濃厚,。令人吃驚的是,，對于天然氣中其他含量較多的烴類（乙烷,、丙烷和丁烷）的命運,，人們所做的研究工作相對來說似乎非常少?，F(xiàn)在,，研究人員從墨西哥灣和加利福尼亞灣烴類滲出區(qū)收集到的沉積物中獲得了能夠在與天然氣層中相似的缺氧條件下利用丙烷和丁烷的微生物培養(yǎng),。這些從生物化學(xué)角度來看不同尋常的細菌，可能是造成人們在海洋滲出氣和其他含氣層的氣體中所觀測到的變化的原因,。
Nature 449, 898-901 (18 October 2007) | doi:10.1038/nature06200; Received 24 October 2006; Accepted 30 August 2007; Published online 19 September 2007
Anaerobic oxidation of short-chain hydrocarbons by marine sulphate-reducing bacteria
Olaf Kniemeyer1,7, Florin Musat1, Stefan M. Sievert2, Katrin Knittel1, Heinz Wilkes3, Martin Blumenberg4, Walter Michaelis4, Arno Classen5, Carsten Bolm5, Samantha B. Joye6 & Friedrich Widdel1
Max Planck Institute for Marine Microbiology, Celsiusstrae 1, D-28359 Bremen, Germany
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02536, USA
GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany
Institute of Biogeochemistry and Marine Chemistry, Bundesstrae 55, University of Hamburg, 20146 Hamburg, Germany
Institute for Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
Department of Marine Sciences, University of Georgia, Athens, Georgia 30602-3636, USA
Present address: Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, D-07745 Jena, Germany.
Correspondence to: Friedrich Widdel1 Correspondence and requests for materials should be addressed to F.W. (Email: [email protected]).
The short-chain hydrocarbons ethane, propane and butane are constituents of natural gas. They are usually assumed to be of thermochemical origin1, but biological formation of ethane and propane has been also observed2. Microbial utilization of short-chain hydrocarbons has been shown in some aerobic species3, 4 but not in anaerobic species of bacteria. On the other hand, anaerobic utilization of short-chain hydrocarbons would in principle be expected because various anaerobic bacteria grow with higher homologues (C6)5. Indeed, chemical analyses of hydrocarbon-rich habitats with limited or no access of oxygen indicated in situ biodegradation of short-chain hydrocarbons6, 7, 8, 9, 10. Here we report the enrichment of sulphate-reducing bacteria (SRB) with such capacity from marine hydrocarbon seep areas. Propane or n-butane as the sole growth substrate led to sediment-free sulphate-reducing enrichment cultures growing at 12, 28 or 60 °C. With ethane, a slower enrichment with residual sediment was obtained at 12 °C. Isolation experiments resulted in a mesophilic pure culture (strain BuS5) that used only propane and n-butane (methane, isobutane, alcohols or carboxylic acids did not support growth). Complete hydrocarbon oxidation to CO2 and the preferential oxidation of 12C-enriched alkanes were observed with strain BuS5 and other cultures. Metabolites of propane included iso- and n-propylsuccinate, indicating a subterminal as well as an unprecedented terminal alkane activation with involvement of fumarate. According to 16S ribosomal RNA analyses, strain BuS5 affiliates with Desulfosarcina/Desulfococcus, a cluster of widespread marine SRB. An enrichment culture with propane growing at 60 °C was dominated by Desulfotomaculum-like SRB. Our results suggest that diverse SRB are able to thrive in seep areas and gas reservoirs on propane and butane, thus altering the gas composition and contributing to sulphide production.
