Effect of various light spectra on amino acids and pigment production of Arthrospira platensis using flat-plate photobioreactor.

Today, the use of nutrients derived from natural bioactive compounds application in the food, pharmaceutical, and cosmetic industries is on the increase. This paper aimed to evaluate the amino acids profile (essential and non-essential) and pigments composition (chlorophyll a , carotenoids, and phycocyanin) of Arthrospira platensis (a blue-green microalga) cultivation in a flat-plate photobioreactor under various types of light-emitting diodes (red: 620-680 nm, white: 380-780 nm, yellow: 570-600nm, blue: 445-480 nm). The maximum biomass concentration (604.96 mg L ^-1 ) occurred when the red LED was applied for cultivation, and the minimum biomass concentration (279.39 mg L ^-1 ) was obtained under blue LED. The sequence of pigments and amino acids concentrations (mg L ^-1 _{culture volume} ) was approximately in accordance with the biomass productivity. It means the red light produces the maximum concentration of pigments (chlorophyll a : 5.42, carotenoids: 2.92, phycocyanin: 67.54 mg L ^-1 ) and amino acids (essential amino acids: 110.47, nonessential amino acids: 179.10 mg L ^-1 ). Nevertheless, when these values were measured in mg per g of dry weight, the utmost contents were observed in microalgal products cultivated under blue LED. These consequences are due to the highest cell productivity and the most extended length of cells that occurred under red and blue LEDs, respectively.