Augmenting Fremyella diplosiphon Cellular Lipid Content and Unsaturated Fatty Acid Methyl Esters Via Sterol Desaturase Gene Overexpression
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Cyanobacteria have immense prospective as a platform for renewable energy; however, a major barrier in achieving optimal productivity is the low lipid yield. Fremyella diplosiphon, a model cyanobacterium, is an ideal biofuel agent due to its desirable fatty acid methyl esters (FAMEs). To enhance lipid content, we overexpressed the sterol desaturase (SD) gene in F. diplosiphon B481 wild type by genetic transformation. This effort resulted in a transformant (B481-SD) with a 64-fold increase in the SD gene at the mRNA transcript level, with no loss in growth and pigmentation. The transformant was persistently grown for over 32 generations indicating long-term stability and vitality. We observed 27.3% and 23% increases in total lipid content and unsaturated FAMEs respectively in B481-SD transesterified lipids with methyl octadecadienoate as the most abundant unsaturated component. In addition, we detected an 81% increase in FAME composition in the transformant compared with the wild type. Theoretical physical and chemical properties confirmed a FAME profile with very high cetane number (65.972–67.494) and oxidative stability (50.493–18.66 h) in the engineered strain. Results of the study offer a promising approach to augment F. diplosiphon total lipid content and unsaturated FAMEs, thus paving the way to enhance biofuel capacity of the organism.
KeywordsAlkane Biofuel Cyanobacteria Sterol desaturase Transcript abundance
The work was partially supported by the National Institutes of Health (UL1GM118973) awarded to Morgan State University and National Science Foundation (DMR 11-57490 and DMR-16-44779) awarded to the National High Magnetic Field Laboratory and the State of Florida.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- 3.Murata, N., Wada, H., & Gombos, Z. (1992). Modes of fatty-acid desaturation in cyanobacteria. Plant and Cell Physiology, 33(7), 933–941.Google Scholar
- 4.Sharathchandra, K., & Rajashekhar, M. (2011). Total lipid and fatty acid composition in some freshwater cyanobacteria. Journal of Algal Biomass Utilization, 2(2), 83–97.Google Scholar
- 8.Kramm, A., Kisiela, M., Schulz, R., & Maser, E. (2012). Short-chain dehydrogenases/reductases in cyanobacteria. The Federation of European Biochemical Societies Journal, 279(6), 1030–1043.Google Scholar
- 9.Nguyen, M. A., & Hoang, A. L. (2016). A review on microalgae and cyanobacteria in biofuel production. Economies and F inances, 1–37.Google Scholar
- 10.Tabatabai, B., Chen, H., Lu, J., Giwa-Otusajo, J., McKenna, A. M., Shrivastava, A. K., & Sitther, V. (2018). Fremyella diplosiphon as a biodiesel agent: identification of fatty acid methyl esters via microwave-assisted direct in situ transesterification. Bioenergy Research, 11(3), 1–10.CrossRefGoogle Scholar
- 12.Tabatabai, B., Gharaie Fathabad, S., Bonyi, E., Rajini, S., Aslan, K., & Sitther, V. (2019). Nanoparticle-mediated impact on growth and fatty acid methyl ester composition in the cyanobacterium, Fremyella diplosiphon. Bioenergy Research In press.Google Scholar
- 18.Folch, J., Lees, M., & Sloane Stanley, G. H. (1957). A simple method for the isolation and purification of total lipids from animal tissues. Journal of Biological Chemistry, 226(1), 497–509.Google Scholar
- 20.Rosenberg, J. N., Kobayashi, N., Barnes, A., Noel, E. A., Betenbaugh, M. J., & Oyler, G. A. (2014). Comparative analyses of three Chlorella species in response to light and sugar reveal distinctive lipid accumulation patterns in the microalga C. sorokiniana. PLoS One, 9(4), e92460.CrossRefGoogle Scholar
- 24.Riss, J., Décordé, K., Sutra, T., Delage, M., Baccou, J. C., Jouy, N., Brune, J. P., Oréal, H., Cristol, J. P., & Rouanet, J. M. (2007). Phycobiliprotein C-phycocyanin from Spirulina platensis is powerfully responsible for reducing oxidative stress and NADPH oxidase expression induced by an atherogenic diet in hamsters. Journal of Agricultural and Food Chemistry, 55(19), 7962–7967.CrossRefGoogle Scholar
- 27.Zhang, M., Barg, R., Yin, M., Gueta-Dahan, Y., Leikin-Frenkel, A., Salts, Y., Shabtai, S., & Ben-Hayyim, G. (2005). Modulated fatty acid desaturation via overexpression of two distinct ω-3 desaturases differentially alters tolerance to various abiotic stresses in transgenic tobacco cells and plants. The Plant Journal, 44(3), 361–371.CrossRefGoogle Scholar