Fig. 5

We determined the possible impact of extracellular enzymes/shuttles from spent-filtrate by incubating 10 new cultures in Fe⁰/CO₂-media spiked with 1 mL spent filtrate (n = 10, T8). These incubations were run in parallel with cultures without spent-filtrate (see Fig. 2). For clarity, we separated the acetogens and methanogens into two panels. In the spent-media spiked community we monitored a the early on-set for acetogenesis after the addition of spent filtrate to Fe⁰-cultures and b inhibition of methanogenesis after the addition of spent-filtrate. Gray lines depict trends for product formation by the acetogens-alone and methanogens-alone after specific inhibition of their competitors. Black lines represent product formation by acetogens and methanogens within the mixed-community