Fig. 2

Measurement parameters recorded by the reactor. Parameters are shown for two runs. During the biomass phase (green shading), cultures were grown with 2% CO₂ in ambient air. Glycolate production was induced by switching aeration to 0.2% CO₂, 35% O₂ in ambient air. Arrows mark the time point of additional 7 mM NH₄⁺ supply. A Internal O₂ concentration. B NH₄⁺ concentration in the reactor medium measured by ion chromatography. C The pH of the culture controlled by D the activity of an automatic pump that added KOH when the medium acidified