Granules of protein-rich microalgal biomass flour having: a particle size distribution, measured on an LS laser granulometer of the COULTER® brand, with a Dmode of 60 to 300 μm and a D4.3 of 70 to 420 μm; an aerated density, measured on a HOSOKAWA Powder Characteristics Tester, of 0.60 to 0.70 g/mL, and a compressibility, measured on a HOSOKAWA Powder Characteristics Tester, of 15 to 25%.