Phototrophic microalgae use light to produce biomass and high-value compounds like pigments and polyunsaturated fatty acids (PUFAs) for food and feed. These biomolecules can be enhanced by flashing light (FL) as short-term treatment during the final growth stage. In Diacronema sp. low frequency FL increased both high light induced compounds (diatoxanthin and DHA) and low-light typical compounds (fucoxanthin and chlorophyll).