Propionate Formation by Opitutus terrae in Pure Culture and in Mixed Culture with a Hydrogenotrophic Methanogen and Implications for Carbon Fluxes in Anoxic Rice Paddy Soil

(A) Changes in the pH₂ in a representative pure culture of O. terrae (◊) and in a representative mixed culture of O. terrae with M. hungatei (⧫), both growing with pectin. (B) Acetate (▿, ▾) and propionate (▵, ▴) concentrations in the same pure culture (open symbols) and mixed culture (closed symbols). (C) Temporal changes in Gibbs free energies for the formation of acetate + H₂ (□, ▪) and acetate + propionate (○, •) in the same pure culture (open symbols) and mixed culture (closed symbols).