FIG 8.
Electron recovery in the fermentation products and cell density of strain RmG11 in pure culture and in coculture with Methanospirillum hungatei. Cultures were grown on 4 mM glucose in 16-mL rubber-stoppered tubes with 5 mL medium. H2 formation is expressed as if H2 were completely dissolved in the liquid phase to facilitate comparison with other products. The amount of H2 produced in the coculture (hatched column) was calculated from the amount of CH4 formed by the hydrogenotrophic partner, assuming a stoichiometry of 4:1. The relative cell density of strain RmG11 was determined by phase-contrast microscopy. The values are means of results obtained with triplicate cultures (± standard deviation) (for details, see Table S3).