Geology topics
Publications and source records attributed to David R. Boone.
Previously published phylogenetic studies of 16S rRNA showed that methylotrophic, slightly halophilic, methanogenic strain GS-16 T (T = type strain) represents a new species of bacterium. We propose the name Methanolobus taylorii for this species; strain GS-16 is the type strain.
Characteristics of an obligately methylotrophic coccoid methanogen (strain GS-16) previously isolated from estuarine sediment are described. Growth was demonstrated on dimethyl sulfide (DMS) or trimethylamine (TMA), but not on methane thiol, methane thiol plus hydrogen, dimethyl disulfide, or methionine. DMS-grown cells were able to metabolize DMS and TMA simultaneously when inoculated into media containing substrate levels of these compounds. However, TMA-grown cells could not metabolize [ 14 C]DMS to 14 CH 4 , although they could convert [ 14 C]methanol to 14 CH 4 . These results suggest that metabolism of DMS proceeds along a somewhat different route than that of TMA and perhaps also that of methanol. The organism exhibited doubling times of 23 and 32 h for growth (25°C) in mineral media on TMA and DMS, respectively. Doubling times were more rapid (∼6 h) when the organisms were grown on TMA in complex broth. In mineral media, the fastest growth on DMS occurred between pH levels of 7.0 and 8.7, at 29°C, and with 0.2 to 0.4 M Na + and 0.04 M Mg 2+ . Somewhat different results occurred for growth on TMA in complex broth. Cells had a moles percent G+C value of 44.5% for their DNA. Growth on DMS, TMA, and methanol yielded stable carbon isotope fractionation factors of 1.044, 1.037, and 1.063, respectively. Fractionation factors for hydrogen were 1.203 (DMS) and 1.183 (TMA).