Biological stoichiometry of oleaginous microalgal lipid synthesis: The role of N:P supply ratios and growth rate on microalgal elemental and biochemical composition

Baoyan Gao, Jing Liu, Chengwu Zhang, Dedmer B. Van de Waal (Corresponding author)

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Abstract

Abstract Biological Stoichiometry is an ecological framework connecting the balance of elements to the functioning of organisms. Here, we applied this framework to study the relationships between carbon:nitrogen:phosphorus (C:N:P) ratios and synthesis of industrial high value biochemicals in the highly oleaginous alga Tetradesmus bernardii. We expected an increase in protein content with increasing cellular N content and decreasing C:N stoichiometry, and an increase in lipid content with increasing C:N and C:P stoichiometry. We tested these hypotheses by exposing T. bernardii to N and P limitation at a range of N:P supply ratios in chemostats set at low and high dilution rates. Following expectations, the cellular protein content increased with the N content, and decreased with cellular C:N ratios across all treatments. Carbohydrates and lipids largely followed the relative availability of C and increased under both N and P limitation, with higher C:N and C:P ratios. Specifically, lipid content increased by 100–125% upon N and P limitation, with a shift towards more neutral lipids at the cost of glycolipids and phospholipids. Generally, we observed a re-allocation of cellular C from protein to carbohydrates upon modest N limitation, and towards lipids under P and severe N limitation. Our results demonstrate stoichiometrically predictable patterns of industrially valuable compounds in an oleaginous microalga.
Original languageEnglish
Pages (from-to)353-361
Number of pages9
JournalAlgal Research
Volume32
DOIs
Publication statusPublished - Jun 2018

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Bibliographical note

6525, AqE

Keywords

  • Oleaginous microalgae
  • Biofuel
  • N:P supply ratios
  • Biochemical stoichiometry
  • Lipid
  • Eco-physiology
  • international

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