Protein: A proposal for a standard parameter to express cyanobacterial biomass in laboratory experiments

This study aims to check if the protein content of a cyanobacterial culture is a reliable biomass parameter for cyanobacteria in laboratory experiments, and therefore can be proposed as a standard biomass parameter in culture work to facilitate comparison of results from different studies. For this purpose, the cyanobacteria Microcystis aeruginosa PCC 7806 and Planktothrix agardhii PT2 were grown in 10-L batch cultures with O2 medium and under iron-, nitrate- or phosphate-limited conditions. A linear correlation was found between protein and biovolume in all cultures during exponential growth. We conclude that protein is a suitable biomass parameter for cyanobacteria in laboratory experiments during balanced growth.