Diatoms as cell factories for high-value products: chrysolaminarin, eicosapentaenoic acid, and fucoxanthin

Abstract

Diatoms are unicellular photosynthetic microalgae existing ubiquitously in marine and freshwater environments. This review focuses on high-value compounds produced from diatoms, including chrysolaminarin (Chrl), eicosapentaenoic acid (EPA), and fucoxanthin (Fx), which can be applied in aquaculture, human health foods, pharmaceuticals, and cosmetics. In addition, this review provides an overview of their biosynthesis in diatoms and technologies for production. EPA and Fx typically accumulate synergistically in diatoms, while Chrl competes with EPA and Fx for carbon precursors. Several diatom strains have been employed that simultaneously accumulate these three compounds, but limitations and challenges still exist during commercialization. To address the bottleneck in biomass and high-value compound production, the optimization of cultivation parameters, the trophic mode, elicitor- or bacteria-assisted stimulations, and genetic modifications via mutant breeding, adaptive evolution engineering, and metabolic engineering have been developed in diatoms to establish improved technologies. Currently, large-scale cultivation of diatoms occurs mostly in open ponds and photobioreactors in autotrophic mode. Mixotrophic cultivation and coextraction approaches for multiple products represent novel strategies for economically enhancing the future production of biomass and high-value compounds on an industrial scale.

Keywords:

• Diatom
• chrysolaminarin
• eicosapentaenoic acid
• fucoxanthin
• culture system
• genetic modification
• coextraction

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgements

Thanks to Prof. Georg Pohnert from Friedrich Schiller University Jena, Germany for his valuable comments on the article.

Disclosure statement

The authors report no declarations of interest.

Additional information

Funding

This work was funded by Guangdong Science and Technology Development Project [2015A020216003], Guangdong Basic and Applied Basic Research Foundation [2019B1515120002], and National Key Research and Development Project [2019YFD0900302].