Effects of nitrogen concentration on growth, fucoxanthin production, and fatty acid composition of the marine diatom Nitzschia sp
- 1College of Fisheries, Guangdong Ocean University
- 2Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture
Abstract
Background: Nitrogen availability strongly regulates growth and biochemical accumulation in marine diatoms, but the magnitude and direction of these responses are strain-specific. Optimizing nitrate supply may therefore provide a practical approach for improving biomass production and the accumulation of high-value metabolites in diatoms.
Methods: The effects of four sodium nitrate (NaNO₃) concentrations (0, 75, 150, and 300 mg L ⁻¹ ) on growth, biomass accumulation, total carotenoid concentration, fucoxanthin production, and fatty acid composition were investigated in the marine diatom Nitzschia sp. The standard f/2 nitrate concentration (75 mg L ⁻¹ NaNO₃) was used as the reference treatment, while 0, 150, and 300 mg L ⁻¹ represented nitrogen starvation, two-fold nitrate enrichment, and four-fold nitrate enrichment, respectively. Growth, biomass, carotenoid, and fucoxanthin parameters were monitored during 12 days of cultivation, and fatty acid composition was determined at the end of the cultivation period.
Results: Nitrate availability strongly affected growth and biochemical accumulation. The highest cell density (2.7 × 10⁶ cells mL ⁻¹ on day 9) and biomass productivity (0.068 ± 0.027 g L ⁻¹ d ⁻¹ on day 6) were obtained under 300 mg L ⁻¹ NaNO₃. Total carotenoid concentration reached its maximum of 2.08 mg L ⁻¹ on day 9 under 150 mg L ⁻¹ NaNO₃. Fucoxanthin content reached its highest value of 8.42 mg g ⁻¹ DW under 300 mg L ⁻¹ NaNO₃ on day 3, accompanied by the highest fucoxanthin productivity (0.689 ± 0.175 mg L ⁻¹ d ⁻¹ ). After 12 days, the highest total identified fatty acid content was obtained under 150 mg L ⁻¹ NaNO₃ (179.39 mg g ⁻¹ DW). EPA and DHA yields also reached their maximum values under 150 mg L ⁻¹ NaNO₃, at 25.12 and 3.52 mg g ⁻¹ DW, respectively.
Conclusion: Nitrate concentration differentially affected biomass production and biochemical accumulation in Nitzschia sp. A high nitrate supply of 300 mg L ⁻¹ NaNO₃ favored biomass accumulation and early fucoxanthin production, whereas 150 mg L ⁻¹ NaNO₃ favored total identified fatty acid accumulation and EPA/DHA yields. These findings demonstrate that nitrate supply should be optimized according to the target product and provide strain-specific baseline information for further optimization of high-value compound production in Nitzschia sp.
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BibTeX
@article{amenorfenyo2026effects,
title = {{Effects of nitrogen concentration on growth, fucoxanthin production, and fatty acid composition of the marine diatom Nitzschia sp}},
author = {David Kwame Amenorfenyo and Wenquan Zheng and Junhao Huang and Ke Peng and Hui Guo and Qianru Li and Feng Li and Yuewen Deng},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1936445},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1936445/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Effects of nitrogen concentration on growth, fucoxanthin production, and fatty acid composition of the marine diatom Nitzschia sp
AU - David Kwame Amenorfenyo
AU - Wenquan Zheng
AU - Junhao Huang
AU - Ke Peng
AU - Hui Guo
AU - Qianru Li
AU - Feng Li
AU - Yuewen Deng
PY - 2026
DA - 2026/10/14
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1936445
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1936445/full
AB - Background: Nitrogen availability strongly regulates growth and biochemical accumulation in marine diatoms, but the magnitude and direction of these responses are strain-specific. Optimizing nitrate supply may therefore provide a practical approach for improving biomass production and the accumulation of high-value metabolites in diatoms. Methods: The effects of four sodium nitrate (NaNO₃) concentrations (0, 75, 150, and 300 mg L ⁻¹ ) on growth, biomass accumulation, total carotenoid concentration, fucoxanthin production, and fatty acid composition were investigated in the marine diatom Nitzschia sp. The standard f/2 nitrate concentration (75 mg L ⁻¹ NaNO₃) was used as the reference treatment, while 0, 150, and 300 mg L ⁻¹ represented nitrogen starvation, two-fold nitrate enrichment, and four-fold nitrate enrichment, respectively. Growth, biomass, carotenoid, and fucoxanthin parameters were monitored during 12 days of cultivation, and fatty acid composition was determined at the end of the cultivation period. Results: Nitrate availability strongly affected growth and biochemical accumulation. The highest cell density (2.7 × 10⁶ cells mL ⁻¹ on day 9) and biomass productivity (0.068 ± 0.027 g L ⁻¹ d ⁻¹ on day 6) were obtained under 300 mg L ⁻¹ NaNO₃. Total carotenoid concentration reached its maximum of 2.08 mg L ⁻¹ on day 9 under 150 mg L ⁻¹ NaNO₃. Fucoxanthin content reached its highest value of 8.42 mg g ⁻¹ DW under 300 mg L ⁻¹ NaNO₃ on day 3, accompanied by the highest fucoxanthin productivity (0.689 ± 0.175 mg L ⁻¹ d ⁻¹ ). After 12 days, the highest total identified fatty acid content was obtained under 150 mg L ⁻¹ NaNO₃ (179.39 mg g ⁻¹ DW). EPA and DHA yields also reached their maximum values under 150 mg L ⁻¹ NaNO₃, at 25.12 and 3.52 mg g ⁻¹ DW, respectively. Conclusion: Nitrate concentration differentially affected biomass production and biochemical accumulation in Nitzschia sp. A high nitrate supply of 300 mg L ⁻¹ NaNO₃ favored biomass accumulation and early fucoxanthin production, whereas 150 mg L ⁻¹ NaNO₃ favored total identified fatty acid accumulation and EPA/DHA yields. These findings demonstrate that nitrate supply should be optimized according to the target product and provide strain-specific baseline information for further optimization of high-value compound production in Nitzschia sp.
SN - 1664-462X
ER -