Figure 8. OD₇₅₀ measurements can be corrected using flow cytometry to yield reliable biomass estimates.

(a) OD₇₅₀ calibration constants (i.e. the slope of OD₇₅₀ vs dry weight biomass) were measured for a range of C. vulgaris cultures at different growth stages (with different average cell diameter). These values were plotted against flow cytometry (peak SSC-W) measurements taken on the same cultures. (b) Using this calibration curve, biomass dry weight was then predicted for a different set of previous cultures for which both biomass and OD₇₅₀ were known. Comparison of the predicted biomass and measured biomass demonstrates a linear relationship (r² = 0.981), suggesting the use of FC measurements to correct OD₇₅₀ measurements enables a linear relationship to be established between OD₇₅₀ and biomass dry weight regardless of the cell morphology or culture stage.