Growth of the cryptophyte microalga <i>Rhodomonas salina</i> (Wislouch) D. R. A. Hill & R. Wetherbee, 1989 under different cultivation conditions
Temperature and irradiance effect was studied on the specific growth rate and biomass accumulation of the cryptophyte alga Rhodomonas salina. Optimal conditions for its cultivation were determined allowing to obtain the maximum biomass. R. salina was cultivated on the Conway medium (in our own modification) at a temperature of (20 ± 1), (24 ± 1), and (28 ± 1) °C and irradiance of 13, 67, 135, and 202 μmol photons·m⁻²·s⁻¹. As shown, an increase in temperature up to above-optimal values resulted in a decrease of the microalga growth rate and biomass. For R. salina, there were no significant differences in growth rates at irradiance of 135 and 202 μmol photons·m⁻²·s⁻¹ (μ values were of (0.69 ± 0.04) and (0.64 ± 0.02) day⁻¹, respectively). The microalga growth slowed down at low irradiance (13 μmol photons·m⁻²·s⁻¹) (μ value was of (0.33 ± 0.03) day⁻¹). The maximum biomass [(3.74 ± 0.28) g·L⁻¹] was obtained at the optimal temperature [(24 ± 1) °C] and irradiance of 135 μmol photons·m⁻²·s⁻¹. Under optimal cultivation conditions, maximum accumulation of proteins was registered at the exponential growth phase (29 %), and maximum accumulation of lipids was recorded at the stationary phase (41 %).