DVM Tri-culture

A three-member synthetic consortium consisting of Desulfovibrio vulgaris (Dv), Methanococcus maripaludis (Mm), and Methanosarcina barkeri (Mb) that converts lactate to methane under varying sulfate conditions. D. vulgaris oxidizes lactate to acetate, CO2, and H2. Both methanogens (Mm and Mb) can consume the H2 produced by Dv, with Mm being a hydrogenotrophic methanogen and Mb capable of using both H2-CO2 and acetate for methanogenesis. The community demonstrates differential responses to geochemical gradients, particularly sulfate availability. In the absence of sulfate, all three species co-exist and methane production increases by almost 100% compared to Dv-Mm co-cultures. However, increasing sulfate levels shift community dynamics as Dv preferentially uses sulfate as an electron acceptor, creating competitive situations for both methanogens. This system provides insights into how geochemical gradients (particularly sulfate) regulate microbial interactions and methane production in anaerobic environments.