2.2. Sample preparation
All four microalgae were harvested by centrifugation at 4000 rpm for 10 min; the resulting microalgal pellets were washed twice using either 0.5 mol L− 1 NH4HCO3 or distilled water for marine or fresh water species, respectively. The washed microalgal pellets were dried at 60 °C for 24 h to a consistent weight and then milled and sieved to obtain particles that were less than 200 μm in size. The samples were stored in a desiccator prior to testing.