Rhodomonas cultivation under different light intensity and nutrients availability
Microalgae are considered as a very promising alternative for many applications in industry such as cosmetics, food, feed and biofuel production. The main advantage of microalgae is their high productivity compared to conventional crops, their ability to sustainably produce proteins, carotenoids, fatty acids and carbohydrates and they can be cultivated at non-arable land.
The ability of these microorganisms to readily adapt to growth fluctuating conditions, attributed to their metabolic flexibility, constitutes an advantage in modulating their biomass composition for commercial purposes. Thus, strategies like the manipulation of parameters such as media nutrient concentrations can be used in order to modify the nature, amount and composition of the product synthesized.
Photons can be absorbed as energy source. Both light intensity and quality (colour or wavelength) influence the light use efficiency. In microalgae low irradiance may limit photosynthesis, but high irradiance may cause photo inhibition. Hence, irradiance can influence the production and composition in microalgae. As a result it may be possible to optimize growth and desirable biochemical quality by manipulating light intensity.
In many of the photosynthetic organisms the saturation level is at 25% of the full solar light intensity and the remaining light is wasted as heat and fluorescence. In the sea, the first layers of green algae consume all light energy that chlorophyll needs and the rest of the light, that penetrates deeper, is absorbed by phycobiliproteins of other algae species. Phycobiliproteins are photosynthetic light harvesting pigments found in cyanobacteria, red algae and cryptomonads and are able to harvest light in a spectral region where light absorption of chlorophyll is inefficient (450-750nm).
Rhodomonas is a cryptophyte species, which exploits phycoerythrin 545 (PE545) as the primary light-harvesting antenna. In this project Rhodomonas will be cultivated under different light intensities and nutrients availability in order to investigate the impact that these parameters have on the biomass productivity and composition. Moreover, the effect of day:night cycle will be in studied for the same species of microalgae.