Abstract
AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 22:141-158 (2014) - DOI: https://doi.org/10.3354/ab00595 Theme Section: Environmental forcing of aquatic primary productivity Synergistic effect of UV radiation and nutrient limitation on Chlorella fusca (Chlorophyta) cultures grown in outdoor cylindrical photobioreactors I. Malpartida1, C. G. Jerez1, M. M. Morales2, P. Nascimento3, I. Freire3, J. Ezequiel4, R. M. Rico1, E. Peralta1, J. R. Malapascua1, Y. Florez1, J. Masojidek5, R. Abdala1, F. L. Figueroa1, E. Navarro6,* 1Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain 2Department of Chemical Engineering, University of Almería, Almería, Spain 3Department Microbiology and Parasitology, Faculty of Biology-CIBUS, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain 4Departamento de Biologia and CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal 5Academy of Sciences, Institute of Microbiology, Opatovickýmlýn, 37981 Trěboň, Czech Republic 6Pyrenean Institute of Ecology (CSIC), Av. Montañana 1005, Zaragoza 50059, Spain *Corresponding author: enrique.navarro@ipe.csic.es ABSTRACT: This study assessed the interactive effects of UVR and nutrient depletion on Chlorella fusca cultures on the production and accumulation of particular biomolecules. To accomplish this, algae were grown for 5 d in outdoor thin-layer cascade cultivators under 3 nutrient treatments (full nutrients, -N and -S) and then transferred to outdoor cylindrical photobioreactors for another 5 d. Cultures were then exposed to full solar radiation (PAB) and decreased UVR. During the last 5 d, bio-optical properties, photosynthetic activity, pigments, biochemical composition and oxidative stress were assessed. Initially, nutrient depletion caused changes in productivity and cell number in a manner that affected biochemical composition. After 3 d, the percentage of lipids in the cultures under N deprivation reached values appropriate for being used as feed or food additives or for energy applications (35% of lipid content), regardless of the light conditions. A longer exposure (5 d) resulted in interactive effects of light and nutrient conditions. Specifically, PAB increased lipid content in all cases (1.3- to 2.3-fold), but particularly under S deprivation. Longer exposure to PAB also increased oxidative stress in UVR and nutrient-limited treatments (-N and -S). These results showed that the benefits expected from nutrient depletion (increase in biomolecule content e.g. lipids, carbohydrates and pigments) were modulated by the negative effects of algal UVR acclimation costs. KEY WORDS: Bio-optic · Chlorella fusca · In vivo chlorophyll fluorescence · Photosynthetic pigments · UV radiation · Lipids · Lipid peroxidation · Proteins · Biochemical composition Full text in pdf format PreviousNextCite this article as: Malpartida I, Jerez CG, Morales MM, Nascimento P and others (2014) Synergistic effect of UV radiation and nutrient limitation on Chlorella fusca (Chlorophyta) cultures grown in outdoor cylindrical photobioreactors. Aquat Biol 22:141-158. https://doi.org/10.3354/ab00595 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 22. Online publication date: November 20, 2014 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2014 Inter-Research.
Highlights
During the last 50 yr, microalgae have been cultivated in both out- and indoor systems to produce biomass used as food or feed or for the extraction of high-value molecules
N is needed for the synthesis of proteins, and N deprivation increases the sensitivity of photosynthesis to UVR in several organisms (Litchman et al 2002, Bouchard et al 2008) due to less efficient repair of UVB damage that depends on N compounds
Based on the rationale previously presented, the working hypothesis was that the expected benefits from nutrient depletion would be modulated by negative direct effects and decreased biomass productivity provoked by an increased exposure to UVR
Summary
During the last 50 yr, microalgae have been cultivated in both out- and indoor systems to produce biomass used as food or feed or for the extraction of high-value molecules. Nutrient deprivation (−S, −P, −N, etc.) results in a decrease of growth rate and photosynthetic rates by both direct (reduction of the synthesis of certain biomolecules) and indirect effects (reduction of protection or repair mechanisms). N is needed for the synthesis of proteins, and N deprivation increases the sensitivity of photosynthesis to UVR in several organisms (Litchman et al 2002, Bouchard et al 2008) due to less efficient repair of UVB damage that depends on N compounds. Based on the rationale previously presented, the working hypothesis was that the expected benefits from nutrient depletion (increase of certain biomolecules, such as lipids, carbohydrates and pigments) would be modulated by negative direct effects (i.e. algal acclimation costs) and decreased biomass productivity provoked by an increased exposure to UVR
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