Thraustochytrids as a promising source of fatty acids, carotenoids, and sterols: bioactive compound biosynthesis, and modern biotechnology

Abstract

Thraustochytrids are eukaryotes and obligate marine protists. They are increasingly considered to be a promising feed additive because of their superior and sustainable application in the production of health-benefiting bioactive compounds, such as fatty acids, carotenoids, and sterols. Moreover, the increasing demand makes it critical to rationally design the targeted products by engineering industrial strains. In this review, bioactive compounds accumulated in thraustochytrids were comprehensively evaluated according to their chemical structure, properties, and physiological function. Metabolic networks and biosynthetic pathways of fatty acids, carotenoids, and sterols were methodically summarized. Further, stress-based strategies used in thraustochytrids were reviewed to explore the potential methodologies for enhancing specific product yields. There are internal relationships between the biosynthesis of fatty acids, carotenoids, and sterols in thraustochytrids since they share some branches of the synthetic routes with some intermediate substrates in common. Although there are classic synthesis pathways presented in the previous research, the metabolic flow of how these compounds are being synthesized in thraustochytrids still remains uncovered. Further, combined with omics technologies to deeply understand the mechanism and effects of different stresses is necessary, which could provide guidance for genetic engineering. While gene-editing technology has allowed targeted gene knock-in and knock-outs in thraustochytrids, efficient gene editing is still required. This critical review will provide comprehensive information to benefit boosting the commercial productivity of specific bioactive substances by thraustochytrids.

Graphical Abstract

HIGHLIGHT

• Thraustochytrids are considered a promising and sustainable nutrient source for long-chain unsa turated fatty acids, carotenoids, and sterols production with impressive biosynthetic capacity.

• The interactive relationships between the biosynthesis and metabolism flows of fatty acids, carotenoids, and sterols are summarized.

• The comprehensive information of multi-omics including genome, transcriptome, proteome, and metabolism for various species of Thraustochytrids has also been concluded.

• Potential gene-engineering methodologies for enhancing bioactive substance yields are explored.

Keywords:

• Thraustochytrid
• fatty acid
• carotenoid
• sterol
• stress
• gene editing

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Chinese National Key R & D Project for Synthetic Biology [2018YFA0902500], Natural Science Foundation of Guangdong Province [2021A1515012557], Shenzhen Basic Research Projects [JCYJ20180507182405562], the National Natural Science Foundation of China [41876188], Joint R&D Project of Shenzhen-Hong Kong Innovation [Grant No. SGLH20180622152010394], Hong Kong Innovation and Technology Commission TCFS [GHP/087/18SZ], Natural Science Foundation of Shenzhen [Grant No. KQJSCX20180328093806045], Guangxi Innovation Drive Development Special Fund [Gui Ke AA18242047], Funding for the Construction of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) and Grant Plan for Demonstration City Project for Marine Economic Development in Shenzhen (No.86) to Dr. Zhangli Hu. The authors also gratefully acknowledge the financial support by Taiwan’s Ministry of Science and Technology under grant nos. 110-3116-F-006 -003, 110-2221-E-029-004-MY3, and 110-2621-M-029-001.