Comparative lipidomic studies of Scenedesmus sp. (Chlorophyceae) and Cylindrotheca closterium (Bacillariophyceae) reveal their differences in lipid production under nitrogen starvation

• Published in: Journal of phycology 2019-12, Vol.55 (6), p.1246-1257
• Main Authors: Wang, Song, Sirbu, Diana, Thomsen, Laurenz, Kuhnert, Nikolai, Ullrich, Matthias S., Thomsen, Claudia, Li, Y.
• Format: Article
• Language: English
• Subjects: Algae; Aquatic plants; Bacillariophyceae; Biodiesel fuels; Biofuels; Biomass; Biomaterials; Biomedical materials; Chlorophyceae; Chloroplasts; Closterium; Cylindrotheca closterium; Diatoms; Endoplasmic reticulum; fatty acid; Fatty acids; Food production; Freshwater; Fuels; Functional foods & nutraceuticals; glycolipids; Growth kinetics; HPLC‐MS; Inland water environment; Ionization; Kinetics; lipid; Lipidomics; Lipids; Liquid chromatography; Mass production; Mass spectrometry; Mass spectroscopy; Metabolites; Microalgae; Nitrogen; Phytoplankton; Polyunsaturated fatty acids; Profiles; Scenedesmus; Species; Starvation; triacylglycerol; Triglycerides
• ISSN: 0022-3646; 1529-8817
• DOI: 10.1111/jpy.12887

Microalgae are a promising resource for the highly sustainable production of various biomaterials (food and feed), high‐value biochemicals, or biofuels. However, factors influencing the valued lipid production from oleaginous algae require a more detailed investigation. This study elucidates the variations in lipid metabolites between a marine diatom (Cylindrotheca closterium) and a freshwater green alga (Scenedesmus sp.) under nitrogen starvation at the molecular species level, with emphasis on triacylglycerols using liquid chromatography–electrospray ionization mass spectrometry techniques. A comprehensive analysis was carried out by comparing the changes in total lipids, growth kinetics, fatty acid compositions, and glycerolipid profiles at the molecular species level at different time points of nitrogen starvation. A total of 60 and 72 triacylglycerol molecular species, along with numerous other polar lipids, were identified in Scenedesmus sp. and C. closterium, respectively, providing the most abundant triacylglycerol profiles for these two species. During nitrogen starvation, more triacylglycerol of Scenedesmus sp. was synthesized via the “eukaryotic pathway” in the endoplasmic reticulum, whereas the increase in triacylglycerol in C. closterium was mainly a result of the “prokaryotic pathway” in the chloroplasts after 96 h of nitrogen starvation. The distinct responses of lipid synthesis to nitrogen starvation exhibited by the two species indicate different strategies of lipid accumulation, notably triacylglycerols, in green algae and diatoms. Scenedesmus sp. and Cylindrotheca closterium could serve as excellent candidates for the mass production of biofuels or polyunsaturated fatty acids for nutraceutical purposes.