Fig. 4

Influence of methanogenesis on competitive fitness of butyrogens in a synthetic gut community. Fold change in relative abundance of F. prausnitzii, E. rectale, and R. intestinalis in a 9-species synthetic human gut community with the addition of M. smithii compared to the same community without M. smithii. Relative abundance was quantified at the end of three successive 24-h subcultures (first subculture in light gray, second in dark gray, third in black), with a new inoculum of M. smithii added to the appropriate cultures at each passage. For each species, there were five replicate cultures in each condition. Statistical significance calculated from relative abundance values using two-sided Student’s two-sample t-tests (*p < 0.05; **p < 0.01; ***p < 0.001)