Fig. 1
Biovolume-specific optical density and average cell size of C. vulgaris at different physiological states. Depending on the physiological state observed, the cells significantly differ in their optical properties and cell size. Thereby, biomass determination across different states by either optical signals or cell number is distorted. Cell samples originated from phototrophic shaking flask cultivations. Error bars deviated from samples (biological replicates) of the respective fermentation phases (n ≥ 3)