Togayhan KUTLUK, Necla ALTIN, Başar UYAR, Nurcan KAPUCU

Effect of Different Nitrogen Sources on the Growth and Lipid Accumulation of Chlorella variabilis

Nitrogen is one of the major elements required for growth and other physiological activities of microalgae. Microalgae can use different forms of nitrogen such as nitrate, nitrite, ammonium, and urea. Although the type of nitrogen used by microalgae depends on the species, microalgae usually prefer ammonia as a nitrogen source and the usual order of preference is ammonium, urea, nitrate, and nitrite. However, types of nitrogen sources and their concentrations affect the growth of microalgae cultures and their biochemical structures. It has been reported in many studies that microalgae accumulate more lipids under nitrogen starvation growth conditions. Therefore,growth and lipid accumulation behavior of microalgae Chlorella variabilisin growth medium (BG11) containing different types of nitrogen source [sodium nitrate (NaNO3), ammonium chloride (NH4Cl) and urea(CH4N2O)] was investigated in this work. Maximum cell concentration (1.59 g/L) and growth rate (0.054/h) were obtained in NH4Cl containing photobioreactor, whereas highest lipid content (16.4%) and productivity (4.21 mg/L.day) was obtained in CH4N2O containing photobioreactor. Compared to the other nitrogen sources, NaNO3 did not significantly improve the growth rate and the lipid productivity. According to the results, microalgae can be considered as a raw material for biodiesel production applications in the future.

Keywords:

biodiesel, Chlorella variabilis, microalgae oil, nitrogen stress,

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Siaut M, Heijde M, Mangogna M, Montsant A, Coesel S, Allen A, Bowler C. 2007. Molecular toolbox for studying diatom biology in Phaeodactylum tricornutum. Gene,406(1), 23-35.
Gökpınar Ş. 1991. Effect of Change of Temperature on Inorganic Nitrogen Assimilation of Five Important Sea Flagellat in Aquaculture, Doktora Tezi, Dokuz Eylül Üniversitesi, Deniz Bilimleri ve Teknolojisi Enstitüsü, İzmir, , 20260.
Xu N, Zhang X, Fan X, Han L, Zeng C. 2001. Effects of Nitrogen Source and Concentration on Growth Rate and Fatty Acid Composition of Ellipsoidion sp.(Eustigmatophyta), Journal of Applied Phycology, 13(6), 463-469.
Shifrin NS, Sallie WC. 1981. Phytoplankton Lipits: Interspecific Differences and Effects of Nitrate, Silicate and Light‐Dark Cycles, Journal of phycology, 17(4), 374-384.
Sukenik C. Y. A., Berner T. 1989 Regulation of Fatty Acid Composition by Irradiance Level in the Eustigmatophyte Nannochloropsis sp, Journal of Phycology, 25(4) 686- 692.
Grobbelaar JU. 2004. Algal Nutrition‒Mineral Nutrition, Handbook of microalgal culture: biotechnology and applied phycology, 95-115.
Bligh EG, & Dyer WJ, 1959. A rapid method of total lipit extraction and purification. Canadian journal of biochemistry and physiology, 37(8), 911-917.
Sharma AK, Sahoo PK, Singhal S. 2015. Influence of different nitrogen and organic carbon sources on microalgae growth and lipid production Journal of Pharmacy and Biological Sciences 10, 48-53
Arumugam M, Agarwal A, Arya MC, Ahmed Z. 2013. Influence of nitrogen sources on biomass productivity of microalgae Scenedesmus bijugatus, Bioresour ceTechnology, 131, 246–249.
Sweta MS, Sunny SS, MA, Rasheed PLS, Hasan RSZ. 2017. Effect of Various Nitrogen Sources on Microalgal Growth and Lipid Content in Chlorella pyrenoidosa NCIM 2738 and ANK-1. Int.J.Curr.Microbiol.App.Sci. 6(8): 3099-3108.
Qiang Lin, and Junda Lin, Effects of nitrogen source and concentration on biomass and oil production of a Scenedesmus rubescens like microalga, , Bioresour Technol 102(2), 2011, 1615-1621