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

TY - JOUR

T1 - Biological stoichiometry of oleaginous microalgal lipid synthesis: The role of N:P supply ratios and growth rate on microalgal elemental and biochemical composition

AU - Gao, Baoyan

AU - Liu, Jing

AU - Zhang, Chengwu

AU - Van de Waal, Dedmer B.

N1 - 6525, AqE; Data archiving: data archived in Dryad

PY - 2018/6

Y1 - 2018/6

N2 - 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.

AB - 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.

KW - Oleaginous microalgae

KW - Biofuel

KW - N:P supply ratios

KW - Biochemical stoichiometry

KW - Lipid

KW - Eco-physiology

KW - international

UR - https://doi.org/10.5061/dryad.2rbnzs7kn

U2 - 10.1016/j.algal.2018.04.019

DO - 10.1016/j.algal.2018.04.019

M3 - Article

SN - 2211-9264

VL - 32

SP - 353

EP - 361

JO - Algal Research

JF - Algal Research

ER -