Increase in polyunsaturated fatty acids and carotenoid accumulation in the microalga Golenkinia brevispicula (Chlorophyceae) by manipulating spectral irradiance

Microalgal biotechnology offers a promising platform for the sustainable production of diverse renewable bioactive compounds. The main difference from other microbial bioprocesses is the crucial role that light plays for cultures since it can be used as a source of environmental information to control metabolic processes. Therefore, we can use these criteria to design a bioprocess that aims to stimulate the accumulation of target molecules by controlling light exposure. We study the effect on biochemical and photobiological responses of Golenkiniabrevispicula FAUBA-3 to the exposition of different spectral irradiances (high-fluence PAR of narrow yellow spectrum complemented with low intensity of monochromatic radiations of red, blue, and UV-A) under pre-stress and salinity stress conditions. High light coupled to salinity stress affected the photosynthetic activity and photoprotection mechanisms as shown by maximal quantum yield ( F/F) and non-photochemical quenching (NPQ ) reduction, respectively. High light treatments combined with the proper dose of UV-A radiation under salinity stress induced the highest carotenoid content (2.75 mg g DW ) composed mainly of lutein and β-carotene, and the highest lipid accumulation (35.3 % DW) with the highest PUFA content (ALA (C18:3) and LA (C18:2)). Our study can guide the strategies for commercial indoor production of G. brevispicula for high-value metabolites.