Biochemical components obtained by microalgal biomass can be induced by specific wavelengths and processed to high value food/feed supplements or pharma- and nutraceuticals. Two biotechnologically relevant microalgae, Nannochloropsis oculata and Tetraselmis chuii, were exposed to non-tailored LEDs light sources emitting either mono- or multichromatic light with low red but significant blue (<450 nm) photon content, or tailored light sources with high blue or high red photon emissions: fluorescent light (FL), di- or multichromatic LED mixes. Growth of N. oculata and T. chuii under tailored light resulted in a approximate to 24% increase of the average biomass productivity as compared to cultures lit by non-tailored light sources. FL induced the highest C:N ratios in both algae (N. oculata: 7.91 +/- 0.09 and T. chuii: 11.29 +/- 0.03), highest total lipid (48.37 +/- 1.07%) in N. oculata and carbohydrate (55.31 +/- 1.02%) in T. chuii biomass. Among non-tailored light sources, monochromatic LEDs with emission peaks 465, 630 and 660 nm induced a approximate to 29% increase of carbohydrates and a approximate to 20% decrease of protein levels as compared to LEDs peaking at 405 nm and cool-and warm white LEDs. In conclusion, as FL have low photon conversion efficiencies (PCE), particularly within the red wavelength range, LEDs emitting at the 390-450 and 630-690 nm wavebands should be combined for optimal carbon fixation, nitrogen and phosphate uptake.
Author Keywords:Tetraselmis chuii; Nannochloropsis oculata; Light emitting diode (LED); Light spectra; Cell physiology; Biochemical composition
KeyWords Plus:FATTY-ACID-COMPOSITION; MARINE MICROALGAE; RED-LIGHT; WASTE-WATER; SEMICONTINUOUS CULTURES; DIFFERENT IRRADIANCES; LIPID PRODUCTION; ISOCHRYSIS SP; BLUE-LIGHT; NITROGEN