Combination of Light Emitting Diodes (LEDs) for photostimulation of carotenoids and chlorophylls synthesis in Tetradesmus sp.

Abstract

In this work, Tetradesmus sp. was investigated regarding biomass and pigment production. The cultivation of Tetradesmus sp. was carried out in a BG-11 medium in addition to a vertical tubular photobioreactor (PBR) irradiated with different spectral combinations and intensities, within a 24:00 h photoperiod. The LEDs emitting light with white; red; yellow; green and blue spectrum were used alone and/or combined, with intensities varying from 13 to 190 μmol m−2 s−1. ANOVA suggested significant effects of the light combination, intensity and interaction between the factors on biomass, carotenoid and chlorophyll responses. The blue light accelerated the growth of Tetradesmus sp. in all three experiments. The combinations white:green (95 μmol m−2 s−1), red:blue (50 μmol m−2 s−1) and blue (25 μmol m−2 s−1) favored biomass growth; while white:green (190 μmol m−2 s−1), red:green (50 μmol m−2 s−1) and red (25 μmol m−2 s−1) favored the synthesis of carotenoids and chlorophylls. Culture reproduction under the spectral regions favoring pigment synthesis indicated that Tetradesmus sp. was photostimulated to synthesize both pigments, especially with red:green (50,50%) at 50 μmol m−2 s−1, where the highest production of carotenoids (6.09 ± 0.29 mg (g biomass)−1) and chlorophyll a (10.08 ± 0.75 mg (g biomass)−1) was obtained.