abstract
The current focus of algae biotechnology is the production of high-value lipids, and its improvement by employing abiotic perturbations such as nitrogen-induced changes. In the present study, the growth dynamics, nitrogen uptake, pigments, and lipid composition of Chlorellla stigmatophora and Hemiselmis cf. andersenii were studied, in response to low (LN), medium (MN) and high (HN) nitrogen supplementations. Both microalgae responded to increased nitrogen levels by increasing their nitrogen uptake rate and pigment content. However, for lipid accumulation, C. stigmatophora presented a different pattern (LN: 16.56% > MN: 11.51% > HN: 10.95%) to that of H. cf. andersenii (MN: 15.37% > HN: 13.06% > LN: 6.71%). Untargeted gas chromatography-mass spectrometry analysis allowed the visualization of the biochemical diversity of C. stigmatophora and H. cf. andersenii, as well as differences in lipid regulation upon nitrogen-induced changes among species. For instance, glycosyl sterols were only detected for C. stigmatophora samples grown under MN and HN conditions. Moreover, lipid analysis of H. cf. andersenii, before and after alkaline hydrolysis, suggests that wax esters play a key role in the response of this microalga to high nitrogen levels. The cultivation of H. cf. andersenii at MN and HN was shown to be ideal for providing a rich source of omega 3 and polyunsaturated fatty acids for nutraceutical purposes. The hierarchical cluster analysis showed the differential intra- and interspecific effects of nitrogen on lipid composition. The diverse ways by which both microalgae responded to nitrogen-induced changes highlighted the influence of phylogeny on the carbon flux through metabolic networks, and accumulation.
keywords
MARINE MICROALGAE; FATTY-ACIDS; STERYL GLYCOSIDES; GROWTH; BIOSYNTHESIS; SALINA; PLANTS; ALGAE; CELL
subject category
Biotechnology & Applied Microbiology
authors
Fernandes, T; Ferreira, A; Cordeiro, N
our authors
Artur Jorge Faria Ferreira
Professor Coordinatoracknowledgements
This research was partially supported by Portuguese funds through FCT-Foundation for Science and Technology within the scope of UIDB/04423/2020 and UIDP/04423/2020 and the European Territorial Cooperation Programme PCT-MAC 2014-2020 through project REBECA-CCT (MAC/1.1.B/269) . Tomasia Fernandes was financially supported by a doctoral grant from ARDITI (Regional Agency for Development of Research, Technology and Innovation of Madeira, Portugal) , Project M1420095369FSE000002.