title: Optimization of a Nile Red method for rapid lipid determination in autotrophic, marine microalgae is species dependent.
abstract: Several studies have been conducted to develop rapid methods for quantification of lipid content in microalgae, as an alternative for time consuming gravimetric methods. Different studies showed that lipid staining with Nile Red in whole cell suspensions and subsequently quantification by the use of a spectrofluorometric device is a promising method, but a profound optimization and validation is rare. It has already been proven that the correlation curve for quantification is species dependent, but it has not yet been investigated whether this is also the case for the optimization of the Nile Red assay protocol. Therefore, two autotrophic, marine microalgae, Nannochloropsis oculata and T-Isochrysis lutea, strongly differing in e.g. cell wall structure, were selected in this study to investigate whether optimization of the Nile Red assay is species dependent. Besides this, it was checked for one of these species, Nannochloropsis, whether the lipid content, determined by the Nile Red assay, could indeed be correlated with the neutral and/or total lipid content determined by gravimetric methods. It was found that optimization of the Nile Red assay was strongly species dependent. Consequently, optimization has to be done for each species before using the assay. For Nannochloropsis, a good correlation was found between total and neutral lipid content obtained by the Nile Red assay and by gravimetric methods.
authors.affiliation: KU Leuven Kulak, Laboratory Food and Lipids, E. Sabbelaan 53, 8500 Kortrijk, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium. Electronic address: lieselot.balduyck@kuleuven-kulak.be.
authors.forename: Lieselot
authors.initials: L
authors.lastname: Balduyck
authors.affiliation: KU Leuven Kulak, Laboratory Food and Lipids, E. Sabbelaan 53, 8500 Kortrijk, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors.forename: Cedrick
authors.initials: C
authors.lastname: Veryser
authors.affiliation: KU Leuven, Faculty of Engineering Technology, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Gebroeders De Smetstraat 1, 9000 Gent, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Goiris
authors.affiliation: KU Leuven Kulak, Laboratory Food and Lipids, E. Sabbelaan 53, 8500 Kortrijk, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Bruneel
authors.affiliation: KU Leuven Kulak, Laboratory Aquatic Biology, E. Sabbelaan 53, 8500 Kortrijk, Belgium.
authors.forename: Koenraad
authors.initials: K
authors.lastname: Muylaert
authors.affiliation: KU Leuven Kulak, Laboratory Food and Lipids, E. Sabbelaan 53, 8500 Kortrijk, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors.forename: Imogen
authors.initials: I
authors.lastname: Foubert
mesh_terms: D059001:Aquatic Organisms / Q000737:chemistry*; D058087:Haptophyta / Q000737:chemistry*; D008055:Lipids / Q000032:analysis*; D010078:Oxazines / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013194:Staining and Labeling / Q000379:methods*; D058009:Stramenopiles / Q000737:chemistry*; D013997:Time Factors
chemical_list: D008055:Lipids; D010078:Oxazines; C044808:nile red
keywords: Fluorescence; Lipid content; Lipid staining; Microalgae; Nile Red