Internally illuminated photobioreactor using a novel type of light-emitting diode (LED) bar for cultivation of <Emphasis Type="Italic">Arthrospira platensis</Emphasis>

The biochemical properties of Spirulina platensis in an internally illuminated photobioreactor (IlPBR) were investigated under different light-emitted diode (LED) wavelengths; blue (λ_max= 450 and 460 nm), green (λ_max= 525 nm), red (λ_max = 630 and 660 nm), and white (6,500K), with various light intensities (200, 500, 1,000, and 2,000 μmol/m²/sec) were examined. The highest specific growth rate, maximum biomass, and phycocyanin productivity occurred under the red LEDs (0.39/day, 0.10 g/L/day, and 0.14 g/g-cell/day, respectively) at 1,000 μmol/m²/sec; the lowest growth rate was obtained under blue LEDs. Indeed, the size of trichomes was changed into short form under blue LEDs at all light intensities or all LEDs at 2,000 μmol/m²/sec for the first 2 days after inoculation, and S. platensis did not grow in the IlPBR under the dark condition. These results provide a base for different approaches for designing the pilot scale photobioreactor and developing cost-effective light sources.