Synthesis and characterization of fluorescent dyes and their applications for the enhancement of growth rate of Chlorella vulgaris

Abstract Spectral conversion of solar radiation from green to red light can enhance the photosynthesis efficiency of microalgae. This can lead to significant increase in microalgal growth. Four perylene-based fluorescent dyes were synthesized to convert wavelengths of light from green (500–570 nm) to orange-red (580–650 nm). These dyes were applied in microalgal cultivation system using two methodologies: (1) light-converting layer, and (2) light-converting medium. The dyes were dissolved in either ethanol or water to form light-converting layers between microalgae culture and the light source. Under converted light in both set-ups, Chlorella vulgaris cultures showed maximum increase in lipid productivity by 13.00% and 17.15%, and biomass productivity by 31.65% and 37.66% compared to the control. Overall, the cultivation results confirmed beneficial effects of modified light on microalgae cultures both on their lipid and biomass productivities. Note that both growth parameters achieved higher performance in the light-converting medium thereby the effectiveness of the cultivation method was validated.