Fig. S6.

Utilization of O₂ and nitrate as terminal electron acceptors by N. moscoviensis. (A–D) Microrespirometric measurements of O₂ consumption with formate (1 mM initial concentration) as electron donor and in presence or absence of nitrate (5 mM initial concentration) are shown. Curves without symbols depict the O₂ concentrations in the supernatant of a N. moscoviensis pure culture. Curves with symbols depict the nitrite concentrations in the supernatant. Each graph represents an independent experiment, and all experiments were performed with highly similar amounts of biomass. Black arrows indicate the addition of formate to the cultures. Purple arrows indicate the addition of nitrate to cultures containing only formate. The reduction in the O₂ consumption rates in presence of both electron acceptors, and the production of nitrite, show that electrons from formate were distributed to both O₂ and nitrate. Please note that experiments with formate in the total absence of nitrate (blue curves) were carried out only twice (A and B).