RT Journal Article SR Electronic T1 Hydrogen isotope composition of Thermoanaerobacterium saccharolyticum lipids: comparing wild type to a nfn- transhydrogenase mutant JF bioRxiv FD Cold Spring Harbor Laboratory SP 138651 DO 10.1101/138651 A1 Leavitt, William D. A1 Murphy, Sean Jean-Loup A1 Lynd, Lee R. A1 Bradley, Alexander S. YR 2017 UL http://biorxiv.org/content/early/2017/05/17/138651.abstract AB The 2H/1H ratio in microbial fatty acids can record information about the energy metabolism of microbes and about the isotopic composition of environmental water. However, the mechanisms involved in the fractionation of hydrogen isotopes between water and lipid are not fully resolved. We provide data aimed at understanding this fractionation in the Gram-positive obligately thermophilic anaerobe, Thermoanaerobacterium saccharolyticum, by comparing a wild-type strain to a deletion mutant in which the nfnAB genes encoding electron-bifurcating transhydrogenase have been removed. The wild-type strain showed faster growth rates and larger overall fractionation than the mutant strain . The overall trend in growth rate and fractionation, along with the isotopic ordering of individual lipids, is consistent with results reported for the Gram-negative sulfate reducer, Desulfovibrio alaskensis G20.