Benzyl amino purine and gibberellic acid coupled to nitrogen-limited stress induce fatty acids, biomass accumulation, and gene expression in scenedesmus obliquus Article uri icon

abstract

  • The need for renewable energy sources makes microalgae an essential feedstock for biofuels production. The molecular aspects and the response to nitrogen (N)-limited conditions with a phytohormone stimulus in micro-algae have been slightly explored. In this work, Scenedesmus obliquus was used as a study model to analyze the effect of benzyl amino purine (BAP) and gibberellic acid (GA) coupled to nitrogen limitation on cell growth, bio-mass and fatty acids. The selected 10-5 M BAP increased the biomass by 1.44-fold, and 10-6 M GA by 1.35-fold. The total lipids also increased by 2.8 and 1.11-fold, respectively. The 10-5 MBAPand10-6 MGAadditionto S. obliquus cultures at different initial nitrogen percentages (N-0, N-25, and N-50) showed a significant increase in cell growth and biomass productivity compared to the unstimulated cultures. BAP N-0 and GA N-0 produced the highest lipid yields with 55%25 and 50%25, respectively. The lipid profile analysis revealed an increase, particularly in C18:1 and C16:0 fatty acids. Gene expression analysis showed an over-expression of acyl carrying protein (ACP), stearoyl-ACP desaturase (SAD), fatty acid acyl-ACP thioesterase (FATA), and diacylglycerol acyltransferase (DGAT) genes, which were mainly induced by nitrogen limitation. Furthermore, BAP and GA produced a significant over-expression on these genes in the N-replete cultures. This study shows that BAP and GA, coupled to N limitation stress, can be used to increase the biomass and lipid production in S. obliquus for sustainable biofuels. © 2021, Tech Science Press. All rights reserved.

publication date

  • 2021-01-01

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