Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s

• DOI: 10.1089/ast.2015.1355
• Publication Date: 2015-11-05T18:03:50Z
• Authors: Laurence G. Miller; Shaun M. Baesman; Ronald S. Oremland
• Keywords: Enceladus; Mass-independent fractionation; Isotope Analysis

We report the first study of stable carbon isotope fractionation during microbial fermentation acetylene (C 2 H ) in sediments, sediment enrichments, and bacterial cultures.Kinetic effects (KIEs) averaged 3.7 -0.5& for slurries prepared with collected at an intertidal mudflat San Francisco Bay 2.7 -0.2& a pure culture Pelobacter sp.isolated from these sediments.A similar KIE 1.8 -0.7& was obtained methanogenic enrichments derived freshwater Searsville Lake, California.However, C uptake by highly enriched mixed (strain SV7) Lake sediments resulted larger 9.0 -0.7&.These are modest KIEs when compared observed oxidation 1 compounds such as methane methyl halides but comparable to results other compounds.These observations may be useful distinguishing biologically active processes operating distant locales Solar System where is present.These include surface Saturn's largest moon Titan vaporous water-and hydrocarbon-rich jets emanating Enceladus.