Changes in photosynthesis, growth and biomass composition in outdoor Chlorella g120 culture during the metabolic shift from heterotrophic to phototrophic cultivation regime

Up to now, scarce information has been available regarding major photobiochemical changes that accompany the metabolic shift from heterotrophy to phototrophy in microalgae cells. In the present trials the trophic conversion from heterotrophic to phototrophic growth regime was studied in the microalga Chlorella vulgaris g120 grown in outdoor thin-layer cascades. The crucial question was whether Chlorella g120 can undergo the photoacclimation of its photosynthetic apparatus under natural irradiance. As for comparison the phototrophic strain Chlorella vulgaris R-117 was cultured in parallel.