title: Combined effects of nitrogen concentration and seasonal changes on the production of lipids in Nannochloropsis oculata.
abstract: Instead of sole nutrient starvation to boost algal lipid production, we addressed nutrient limitation at two different seasons (autumn and spring) during outdoor cultivation in flat panel photobioreactors. Lipid accumulation, biomass and lipid productivity and changes in fatty acid composition of Nannochloropsis oculata were investigated under nitrogen (N) limitation (nitrate:phosphate N:P 5, N:P 2.5 molar ratio). N. oculata was able to maintain a high biomass productivity under N-limitation compared to N-sufficiency (N:P 20) at both seasons, which in spring resulted in nearly double lipid productivity under N-limited conditions (0.21 g L⁻¹ day⁻¹) compared to N-sufficiency (0.11 g L⁻¹ day⁻¹). Saturated and monounsaturated fatty acids increased from 76% to nearly 90% of total fatty acids in N-limited cultures. Higher biomass and lipid productivity in spring could, partly, be explained by higher irradiance, partly by greater harvesting rate (~30%). Our results indicate the potential for the production of algal high value products (i.e., polyunsaturated fatty acids) during both N-sufficiency and N-limitation. To meet the sustainability challenges of algal biomass production, we propose a dual-system process: Closed photobioreactors producing biomass for high value products and inoculum for larger raceway ponds recycling waste/exhaust streams to produce bulk chemicals for fuel, feed and industrial material.
authors.affiliation: Faculty of Health and Life Sciences, Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnæus University, 391 82 Kalmar, Sweden. martin.olofsson@lnu.se.
authors.forename: Martin
authors.initials: M
authors.lastname: Olofsson
authors.affiliation: Necton SA, Belamandil s/n, 8700-152 Olhão, Portugal. teresa@necton.pt.
authors.forename: Teresa
authors.initials: T
authors.lastname: Lamela
authors.affiliation: Faculty of Health and Life Sciences, Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnæus University, 391 82 Kalmar, Sweden. emmelie.nilsson@lnu.se.
authors.forename: Emmelie
authors.initials: E
authors.lastname: Nilsson
authors.affiliation: IFREMER, Laboratoire de Science et Technologie de la Biomasse Marine (STBM), 44311 Nantes cedex 03, France. jpberge@ifremer.fr.
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: Bergé
authors.affiliation: Necton SA, Belamandil s/n, 8700-152 Olhão, Portugal. vdelpino@necton.pt.
authors.forename: Victória
authors.initials: V
authors.lastname: del Pino
authors.affiliation: Neste Oil, Technology Centre, POB 310, 06101 Porvoo, Finland. pauliina.uronen@nesteoil.com.
authors.forename: Pauliina
authors.initials: P
authors.lastname: Uronen
authors.affiliation: Faculty of Health and Life Sciences, Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnæus University, 391 82 Kalmar, Sweden. catherine.legrand@lnu.se.
authors.forename: Catherine
authors.initials: C
authors.lastname: Legrand
mesh_terms: D018533:Biomass; D005227:Fatty Acids / Q000096:biosynthesis / Q000737:chemistry; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D058433:Photobioreactors; D012621:Seasons; D058009:Stramenopiles / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D008055:Lipids; D009584:Nitrogen