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Carotenoid and fatty acid metabolism in nitrogen-starved Dunaliella salina, a unicellular green microalga

Paper ID Volume ID Publish Year Pages File Format Full-Text
23647 43460 2012 7 PDF Available
Title
Carotenoid and fatty acid metabolism in nitrogen-starved Dunaliella salina, a unicellular green microalga
Abstract

Nitrogen availability and light intensity affect β-carotene overproduction in the green alga Dunaliella salina. Following a previous study on high-light stress, we here report on the effect of nitrogen depletion on the growth characteristics and β-carotene as well as fatty acid metabolism of D. salina under a constant light regime in a turbidostat. Upon nitrogen depletion, the biomass yield on absorbed light approximately doubled, due to a transient increase in cell division rate, swelling of the cells and a linear increase of the density of the cells. Simultaneously, β-carotene started to accumulate up to a final intracellular concentration of 14 mg LCV−1 (i.e. 2.7% of AFDW). This β-carotene production accounted for 6% of the increased density of the cells, indicating that other biochemical constituents accumulated as well. Since D. salina accumulates β-carotene in lipid globules, we also determined the fatty acid content and composition of D. salina. The intracellular concentration of the total fatty acid pool did not change significantly during nitrogen starvation, indicating that β-carotene and total fatty acid accumulation were unrelated, similar to what was found previously for high-light treated cells. However, for both high-light and nitrogen stress, β-carotene accumulation negatively correlated with the degree of unsaturation of the total fatty acid pool and, within the individual fatty acids, correlated positively with oleic acid biosynthesis, suggesting that oleic acid may be a key component of the lipid-globule-localized triacylglycerols and thereby in β-carotene accumulation.

► Nitrogen depletion leads to a transient increase in biomass yield on light. ► β-carotene accumulation and fatty acid accumulation are not correlated. ► β-carotene accumulation and degree of fatty acid unsaturation correlate negatively. ► β-carotene accumulation correlates with oleic acid biosynthesis.

Keywords
AFDW, ash-free dry weight; LCV, liter cell volume; LRV, liter reactor volumeDunaliella; Turbidostat; Carotenoid; Fatty acid; Nitrogen starvation; Metabolism
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Carotenoid and fatty acid metabolism in nitrogen-starved Dunaliella salina, a unicellular green microalga
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 162, Issue 1, 30 November 2012, Pages 21–27
Authors
, , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us