Stable carbon isotope fractionation during bacterial acetylene fermentation: Potential for life detection in hydrocarbon-rich volatiles of icy planet(oid)s

Astrobiology
By: , and 

Links

Abstract

We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Stable carbon isotope fractionation during bacterial acetylene fermentation: Potential for life detection in hydrocarbon-rich volatiles of icy planet(oid)s
Series title Astrobiology
DOI 10.1089/ast.2015.1355
Volume 15
Issue 11
Year Published 2015
Language English
Publisher Mary Ann Liebert, Inc.
Contributing office(s) National Research Program - Western Branch, San Francisco Bay-Delta, Toxic Substances Hydrology Program
Description 10 p.
First page 977
Last page 986
Online Only (Y/N) N
Additional Online Files (Y/N) N