title: Horizontal or vertical photobioreactors? How to improve microalgae photosynthetic efficiency.
abstract: The productivity of a vertical outdoor photobioreactor was quantitatively assessed and compared to a horizontal reactor. Daily light cycles in southern Spain were simulated and applied to grow the microalgae Chlorella sorokiniana in a flat panel photobioreactor. The maximal irradiance around noon differs from 400 μmol photons m(-2) s(-1) in the vertical position to 1800 μmol photons m(-2) s(-1) in the horizontal position. The highest volumetric productivity was achieved in the simulated horizontal position, 4 g kg culture(-1) d(-1). The highest photosynthetic efficiency was found for the vertical simulation, 1.3g of biomass produced per mol of PAR photons supplied, which compares favorably to the horizontal position (0.85 g mol(-1)) and to the theoretical maximal yield (1.8 g mol(-1)). These results prove that productivity per unit of ground area could be greatly enhanced by placing the photobioreactors vertically.
authors.affiliation: Wageningen University, Bioprocess Engineering, PO Box 8129, 6700 EV Wageningen, The Netherlands. maria.cuaresma@wur.nl
authors.forename: María
authors.initials: M
authors.lastname: Cuaresma
authors.forename: Marcel
authors.initials: M
authors.lastname: Janssen
authors.forename: Carlos
authors.initials: C
authors.lastname: Vílchez
authors.forename: René H
authors.initials: RH
authors.lastname: Wijffels
mesh_terms: D018533:Biomass; D019149:Bioreactors; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D058086:Microalgae / Q000502:physiology*; D010777:Photochemistry; D010788:Photosynthesis
chemical_list: D002734:Chlorophyll; D002338:Carotenoids