The Genome Sequence of the Rumen Methanogen Methanobrevibacter ruminantium Reveals New Possibilities for Controlling Ruminant Methane Emissions
The inclusion of (A) 20 mM methanol or (B) 5 or 10 mM ethanol when M1 was grown on H2 resulted in an increase in culture density (measured as OD600 nm) compared to cultures grown on H2 alone. H2 was added once only, at the time of inoculation, by gassing the cultures with H2 plus CO2 (4∶1) to 180 kPa overpressure. Higher concentrations of ethanol (20 mM) resulted in some inhibition of growth (not shown), and there was no stimulation by isopropanol (5 to 20 mM; not shown). No growth occurred when cultures were supplemented with methanol (A), ethanol (B), or isopropanol (not shown) when no H2 was added, and no methane was formed by those cultures. The symbols in panel are means of 4 replicates, and the thin vertical bars in panel (A) represent one standard error on either side of the mean. Error bars are omitted from panel (B) for the sake of clarity.