Impact Of Combined Monochromatic Light On The Biocomponent Productivity Of Dunaliella Salina

Illumination conditions are crucial factors affecting the growth and biosynthesis of microalgae. In this study, monochromatic red, blue, or the combined red and blue light illumination was applied to Dunaliella salina culture to study the effects of illumination on the growth and biocomponents productivity of the microalga D. salina. The monochromatic blue light (peak wavelength, 455 nm) did not significantly enhance D. salina growth but boosted the cellular contents of lipid, protein, and carbohydrate. Both cellular content and productivity of carotenoid produced by D. salina in the white light control were the highest compared to other monochromatic treatments. Interestingly, simultaneous application of red and blue light in various ratios showed a major boost not only on growth but also on cellular lipid content, and resulted in higher lipid productivity. This result is different from many published literatures reporting the enhancement of biomass or cellular lipid content individually. The optimal ratio of red and blue light was 4:3 (4 dose of red light to 3 dose of blue light), which significantly improved lipid productivity by 35.33% compared to the white light control. The result suggested a monochromatic red and blue light combination of illumination could be employed to increase the biomass yield as well as cellular lipid content of D. salina simultaneously for the production of biofuel.