Effects of Excess and Limited Phosphate on Biomass, Lipid and Fatty Acid Contents and the Expression of Four Fatty Acid Desaturase Genes in the Tropical Selenastraceaen Messastrum gracile SE-MC4
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In this study, the effects of limited and excess phosphate on biomass content, oil content, fatty acid profile and the expression of three fatty acid desaturases in Messastrum gracile SE-MC4 were determined. It was found that total biomass (0.67–0.83 g L−1), oil content (30.99–38.08%) and the duration for cells to reach stationary phase (25–27 days) were not considerably affected by phosphate limitation. However, excess phosphate slightly reduced total biomass and oil content to 0.50 g L−1 and 25.36% respectively. The dominant fatty acids in M. gracile, pamitic acid (C16:0) and oleic acid (C18:1) which constitute more than 81% of the total fatty acids remained relatively high and constant across all phosphate concentrations. Reduction of phosphate concentration to 25% and below significantly increased total MUFA, whereas increasing phosphate concentration to ≥ 50% and ≥ 100% significantly increased total SFA and PUFA content respectively. The expression of omega-3 fatty acid desaturase (ω-3 FADi1, ω-3 FADi2) and omega-6 fatty acid desaturase (ω-6 FAD) was increased under phosphate limitation, especially at ≤ 12.5% phosphate, whereas levels of streoyl-ACP desaturase (SAD) transcripts were relatively unchanged across all phosphate concentrations. The first isoform of ω-3 FAD (ω-3 FADi) displayed a binary upregulation under limited (≤ 12.5%) and excess (200%) phosphate. The expression of ω-6 FAD, ω-3 FAD and SAD were inconsistent with the accumulation of oleic acid (C18:1), linoleic acid (C18:2) and alpha-linolenic acid (C18:3), suggesting that these genes may be regulated indirectly by phosphate availability via post-transcriptional or post-translational mechanisms.
KeywordsMicroalgae Fatty acid desaturase Nutrient starvation Biodiesel Phosphorus limitation
TSC, KAM, AA and SHL conceived and designed the research; KAM conducted the experiments. TSC, KAM, WY, AA and SHL analysed and interpreted data. KAM and WY wrote the manuscript with guidance from TSC, AA and SHL. All authors read and approved the manuscript.
This research project was funded under the Science Fund (Project No: 05-01-12—SF1007) from the Ministry of Agriculture (MOA) Malaysia.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- 7.Álvarez-Díaz, P. D., Ruiz, J., Arbib, Z., Barragán, J., Garrido-Pérez, C., & Perales, J. A. (2014). Lipid production of microalga Ankistrodesmus falcatus increased by nutrient and light starvation in a two-stage cultivation process. Applied Biochemistry and Biotechnology, 174(4), 1471–1483.PubMedCrossRefPubMedCentralGoogle Scholar
- 8.Jazzar, S., Berrejeb, N., Messaoud, C., Marzouki, M. N., & Smaali, I. (2016). Growth parameters, photosynthetic performance, and biochemical characterization of newly isolated green microalgae in response to culture condition variations. Applied Biochemistry and Biotechnology, 179(7), 1290–1308.PubMedCrossRefPubMedCentralGoogle Scholar
- 12.Sipaúba-Tavares, L. H., Millan, R. N., Berchielli, F. A., & Braga, F. M. S. (2011). Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch) Korshikov (Chlorophyta). Acta Scientiarum Biological Sciences, 33, 247–253.CrossRefGoogle Scholar
- 13.Elser, J. J., Bracken, M. E., Cleland, E. E., Gruner, D. S., Harpole, W. S., Hillebrand, H., Ngai, J. T., Seabloom, E. W., Shurin, J. B., & Smith, J. E. (2007). Global analysis of nitrogen and phosphorus limitation of primary producers in freshwater, marine and terrestrial ecosystems. Ecology Letters, 10(12), 1135–1142.PubMedPubMedCentralCrossRefGoogle Scholar
- 15.Ray, K., Mukherjee, C., & Gosh, A. N. (2013). A way to curb phosphorous toxicity in the environment: use of polyphosphate reservoir of cyanobacteria and microalga as a safe alternative phosphorous biofertilizer for Indian agriculture. Environmental Science & Technology, 47, 11378–11379.CrossRefGoogle Scholar
- 20.Michelon, W., Da Silva, M. L. B., Mezzari, M. P., Pirolli, M., Prandini, J. M., & Soares, H. M. (2016). Effects of nitrogen and phosphorus on biochemical composition of microalgae polyculture harvested from phycoremediation of piggery wastewater digestate. Applied Biochemistry and Biotechnology, 178(7), 1407–1419.PubMedCrossRefGoogle Scholar
- 21.Cha, T. S., Chen, J. W., Goh, E. G., Aziz, A., & Loh, S. H. (2011). Differential regulation of fatty acid biosynthesis in two Chlorella species in response to nitrate treatments and the potential of binary blending microalgae oils for biodiesel application. Bioresource Technology, 102, 10633–10640.PubMedCrossRefGoogle Scholar
- 31.Ruangsomboon, S., Ganmanee, M., & Choochote, S. (2013). Effects of different nitrogen, phosphorus, and iron concentrations and salinity on lipid production in newly isolated strain of the tropical green microalga, Scenedesmus dimorphus KMITL. Journal of Applied Phycology, 25(3), 867–874.CrossRefGoogle Scholar
- 39.Domergue, F., Spiekermann, P., Lerchl, J., Beckmann, C., Kilian, O., Kroth, P. G., Boland, W., Zähringer, U., & Heinz, E. (2003). New insight into Phaeodactylum tricornutum fatty acid metabolism. Cloning and functional characterization of plastidial and microsomal Δ12-fatty acid desaturases. Plant Physiology, 131(4), 1648–1660.PubMedPubMedCentralCrossRefGoogle Scholar
- 42.Jusoh, M., Loh, S. H., Chuah, T. S., Aziz, A., & Cha, T. S. (2015). Indole-3-acetic acid (IAA) induced changes in oil content, fatty acid profiles and expression of four fatty acid biosynthetic genes in Chlorella vulgaris at early stationary growth phase. Phytochemistry, 111, 65–71.PubMedCrossRefPubMedCentralGoogle Scholar
- 43.Jusoh, M., Loh, S. H., Aziz, A., & Cha, T. S. (2019). Gibberellin promotes cell growth and induces changes in fatty acid biosynthesis and upregulates fatty acid biosynthesis genes in Chlorella vulgaris UMT-M1. Applied Biochemistry and Biotechnology, 188(2), 450–459.PubMedCrossRefPubMedCentralGoogle Scholar
- 45.O'Quin, J. B., Bourassa, L., Zhang, D., Shockey, J. M., Gidda, S. K., Fosnot, S., Chapman, K. D., Mullen, R. T., & Dyer, J. M. (2010). Temperature-sensitive post-translational regulation of plant omega-3 fatty-acid desaturases is mediated by the endoplasmic reticulum-associated degradation pathway. Journal of Biological Chemistry, 285, 21781–21796.PubMedCrossRefPubMedCentralGoogle Scholar
- 49.Rajwade, A. V., Kadoo, N. Y., Borikar, S. P., Harsulkar, A. M., Ghorpade, P. B., & Gupta, V. S. (2014). Differential transcriptional activity of SAD, FAD2 and FAD3 desaturase genes in developing seeds of linseed contributes to varietal variation in α-linolenic acid content. Phytochemistry, 98, 41–53.PubMedCrossRefPubMedCentralGoogle Scholar