Enhancement of Dunaliella salina growth by using wavelength shifting dyes

The availability of light is one of the key driving factors for photosynthesis. Chlorophyll and accessory pigments absorb light at some of the wavelengths present in the solar spectrum. If all other requirements are available in abundance, introducing more light to the system at wavelengths that can be absorbed will increase the growth rate of microalgae and the final biomass achieved up to the level of photosaturation. Therefore, the effect of shifting the spectrum of light available such that the photons unutilized in photosynthesis are converted to those that can be utilised was investigated. Spectral shifts converting UV light to blue light and green light to red light were carried out using films produced with Coumarin and Solvent Orange respectively. Dunaliella salina (CCAP 19-30) was grown in an airlift photobioreactor (ALB) which was coated with the wavelength shifting films. Dunaliella final biomass in the ALB, as determined by the optical density, were shown to increase by 36.9% for UV to blue light conversion and by 18.8% for green to red light conversion when using a coated ALB compared with an uncoated one.