Fig. 2.

Monocultures and co-cultures were harvested at mid-log growth phase as determined by cumulative pressure. Panel A shows a schematic of the experimental process of cultivating and harvesting co-cultures. A similar process was followed for cultivating and harvesting monocultures, except the seed culture was inoculated with 1 ml of fungus only. Cultures were harvested at pre-determined pressure ranges indicative of the mid-log growth stage for each culturing condition (B and C). Cumulative pressure (psig) is plotted versus hours after inoculation for co-cultures and monocultures grown on biomass and components of biomass—reed canary grass, Avicel^®, and xylan—in Panel B. Cumulative pressure (psig) is plotted versus hours after inoculation for co-cultures and monocultures grown on soluble sugars—glucose and fructose—in Panel C. Pressure readings for co-cultures are indicated by squares and pressure readings for monocultures are indicated by diamonds. Each substrate is color coded according to the key on the plot. Cultures were harvested at the mid-log growth phase, as indicated by the final pressure time point for each sample. Panel D shows long-term methane and hydrogen data produced by co-cultures of the anaerobic fungus C. churrovis and the methanogen M. bryantii on a reed canary grass substrate. Cultures were grown in a complex media formulation, in contrast to cultures harvested for RNA extraction which were grown on MC-. Low levels of accumulated hydrogen indicate stable co-culture over the course of fungal growth