Kinetic Flux Profiling Dissects Nitrogen Utilization Pathways in the Oleaginous Green Alga Chlorella protothecoides

Wei Xiong, Chao Wu, Junbiao Dai, Qingyu Wu

Research output: Contribution to journalArticlepeer-review

23 Scopus Citations

Abstract

As a promising candidate for biodiesel production, the green alga Chlorella protothecoides can efficiently produce oleaginous biomass and the lipid biosynthesis is greatly influenced by the availability of nitrogen source and corresponding nitrogen assimilation pathways. Based on isotope-assisted kinetic flux profiling (KFP), the fluxes through the nitrogen utilization pathway were quantitatively analyzed. We found that autotrophic C. protothecoides cells absorbed ammonium mainly through glutamate dehydrogenase (GDH), and partially through glutamine synthetase (GS), which was the rate-limiting enzyme of nitrogen assimilation process with rare metabolic activity of glutamine oxoglutarate aminotransferase (GOGAT, also known as glutamate synthase); whereas under heterotrophic conditions, the cells adapted to GS-GOGAT cycle for nitrogen assimilation in which GS reaction rate was associated with GOGAT activity. The fact that C. protothecoides chooses the adenosine triphosphate-free and less ammonium-affinity GDH pathway, or alternatively the energy-consuming GS-GOGAT cycle with high ammonium affinity for nitrogen assimilation, highlights the metabolic adaptability of C. protothecoides exposed to altered nitrogen conditions.

Original languageAmerican English
Pages (from-to)116-124
Number of pages9
JournalJournal of Phycology
Volume52
Issue number1
DOIs
StatePublished - 1 Feb 2016

Bibliographical note

Publisher Copyright:
© 2016 Phycological Society of America.

NREL Publication Number

  • NREL/JA-2700-65913

Keywords

  • Chlorella protothecoides
  • GDH pathway
  • GS-GOGAT cycle
  • KFP

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