Coupling and uncoupling of triglyceride and beta-carotene production by Dunaliella salina under nitrogen limitation and starvation

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Oui
Statut de publication : Publié
Année de publication : 2017
Auteurs (6) : BONNEFOND Hubert MOELANTS Nina TALEC Amélie MAYZAUD Patrick BERNARD Olivier SCIANDRA Antoine
Revue scientifique : Biotechnology for Biofuels
Volume : 10
Fascicule : 1
Pages :
DOI : 10.1186/s13068-017-0713-4
URL : https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-017-0713-4
Abstract : Background

Nitrogen starvation and limitation are known to induce important physiological changes especially in lipid metabolism of microalgae (triglycerides, membrane lipids, beta-carotene, etc.). Although little information is available for Dunaliella salina, it is a promising microalga for biofuel production and biotechnological applications due to its ability to accumulate lipid together with beta-carotene.
Results

Batch and chemostat experiments with various degrees of nitrogen limitation, ranging from starvation to nitrogen-replete conditions, were carried out to study carbon storage dynamics (total carbon, lipids, and beta-carotene) in steady state cultures of D. salina. A new protocol was developed in order to manage the very high beta-carotene concentrations and to more accurately separate and quantify beta-carotene and triglycerides by chromatography. Biomass evolution was appropriately described by the Droop model on the basis of the nitrogen quota dynamics.
Conclusions

Triglycerides and beta-carotene were both strongly anti-correlated with nitrogen quota highlighting their carbon sink function in nitrogen depletion conditions. Moreover, these two valuable molecules were correlated each other for nitrogen replete conditions or moderated nitrogen limitations (N:C ratio higher than 0.04). Under nitrogen starvation, i.e., for very low N:C ratio, the dynamic revealed, for the first time, uncoupled part (higher triglyceride accumulation than beta-carotene), possibly because of shortage in key proteins involved in the stabilization of lipid droplets. This study motivates the accurate control of the microalgal nitrogen quota in order to optimize lipid productivity.
Mots-clés : Dunaliella salina Triglycerides Beta-carotene separation Nitrogen starvation/limitation Droop model
Commentaire : -
Tags : PHYTOPULSE
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Citation :
Bonnefond H, Moelants N, Talec A, Mayzaud P, Bernard O, Sciandra A (2017) Coupling and uncoupling of triglyceride and beta-carotene production by Dunaliella salina under nitrogen limitation and starvation. Biotechnol Biofuels 10 | doi: 10.1186/s13068-017-0713-4