Neutral lipids and carbohydrates productivities as a response to the nitrogen status in the Haptophyceae Isochrysis sp. (T-iso): starvation vs. limitation

Thomas Lacour 1 Antoine Sciandra 1, 2 Amélie Talec 1 Patrick Mayzaud 1 Olivier Bernard 2
2 BIOCORE - Biological control of artificial ecosystems
LOV - Laboratoire d'océanographie de Villefranche, CRISAM - Inria Sophia Antipolis - Méditerranée , INRA - Institut National de la Recherche Agronomique
Abstract : Partitioning of the carbon (C) fixed during photosynthesis between neutral lipids (NL) and carbohydrates was investigated in Isochrysis sp. (Haptophyceae) in relation to its nitrogen (N) status. Using batch and nitrate-limited continuous cultures, we studied the response of these energy reserve pools to both conditions of N starvation and limitation. During N starvation, NL and carbohydrate quotas increased but their specific growth rates (specific rates of variation, μCAR and μNL) decreased. When cells were successively deprived and then resupplied with NO3, both carbohydrates and neutral lipids were inversely related to the N quota (N:C). These negative relationships were not identical during N impoverishment and replenishment, indicating a hysteresis phenomenon between N and C reserve mobilizations. Cells acclimated to increasing degrees of N limitation in steady-state chemostat cultures showed decreasing NL quota and increasing carbohydrate quota. N starvation led to a visible but only transient increase of NL productivity. In continuous cultures, the highest NL productivity was obtained for the highest experimented dilution rate (D = 1.0 d−1; i.e., for non N-limited growth conditions), whereas the highest carbohydrate productivity was obtained at D = 0.67 d−1. We used these results to discuss the nitrogen conditions that optimize NL productivities in the context of biofuel production.
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https://hal.inria.fr/hal-00848419
Contributeur : Jean-Luc Gouzé <>
Soumis le : vendredi 26 juillet 2013 - 10:31:41
Dernière modification le : vendredi 12 janvier 2018 - 01:48:35

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Thomas Lacour, Antoine Sciandra, Amélie Talec, Patrick Mayzaud, Olivier Bernard. Neutral lipids and carbohydrates productivities as a response to the nitrogen status in the Haptophyceae Isochrysis sp. (T-iso): starvation vs. limitation. Journal of Phycology, Wiley, 2012, 48 (3), pp.647-656. 〈10.1111/j.1529-8817.2012.01154.x〉. 〈hal-00848419〉

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