Harnessing the sun for microalgae cultures: Photobioreactor design, operation and control for high irradiance areas.
05 / 2006 - 05 / 2010
Introduction: The importance of photoautotrophic microorganisms is based on their potential use for high value compounds, as heavy metals storage cells, for biofuels or as potential source of biomass in animal feed. Efficient utilization of light inside the photobioreactors is one of the major problems in bioreactor design for microalgae biomass production. To overcome this problem reactors have been developed in which optical techniques were used to dilute sunlight as well as photobioreactors with a short light-path. Aim: The aim of this project is to maximize the photosynthetic efficiency of the growing microalgae in a new photoreactor prototype in which outdoor sunlight conditions will be simulated. Research: Flatpanel photobioreactorThe prototype used is a flat panel photobioreactor with a light-path of 14 mm, which is illuminated with red LEDs. The light intensity at the reactor surface can be varied between 0 and 2500 ¦Ìmol m-2 s-1 (PAR, 400-700 nm) to reach exactly the same intensity as measured with a light sensor placed outdoors. In that way the photobioreactor can be operated at outdoor light conditions with optimal control of all other parameters. The reactor will be operated in Huelva (Andaluc¨ªa, Spain) to profit from the high-irradiance clear-sky conditions. The use of species differing in photosynthetic capacity and/or optimum temperature could show the applicability of the production process for different microalgae in this photobioreactor. As such, we use Chlorella sorokiniana as a reference strain because of its high growth rate and its high tolerance to high light and temperature. Besides, Nannochloropsis oculata will enable us to judge photobioreactor performance for microalgae with a lower growth rate and higher sensitive to high light and temperature. Acknowledgements: The research project is supported by LGem, Techno Invent, Technogrow BV and University of Huelva, Spain.