Metabolic Engineering to Improve Docosahexaenoic Acid Production in Marine Protist Aurantiochytrium sp. by Disrupting 2,4-Dienoyl-CoA Reductase

Abstract

Docosahexaenoic acid (DHA) has attracted attention from researchers because of its pharmacological and nutritional importance. Currently, DHA production costs are high due to fermentation inefficiency; however, improving DHA yield by metabolic engineering in thraustochytrids is one approach to reduce these costs. In this study, a high-yielding (53.97% of total fatty acids) DHA production strain was constructed by disrupting polyunsaturated fatty acid beta-oxidation via knockout of the 2,4-dienyl-CoA reductase (DECR) gene (KO strain) in Aurantiochytrium sp. Slight differences in cell growth was observed in the wild-type and transformants (OE and KO), with cell concentrations in stationary of 2.65×106, 2.36×106 and 2.56×106 cells mL-1 respectively. Impressively, the KO strain yielded 21.62% more neutral lipids and 57.34% greater DHA production; moreover, the opposite was observed when overexpressing DECR (OE strain), with significant decreases of 30.49% and 64.61%, respectively. Furthermore, the KO strain showed a prolonged DHA production period with a sustainable increase from 63 to 90 h (170.03 to 203.27 mg g−1 DCW), while that of the wildtype strain decreased significantly from 150.58 to 140.10 mg g−1 DCW. This new approach provides an advanced proxy for the construction of sustainable DHA production strains for industrial purposes and deepens our understanding of the metabolic pathways of Aurantiochytrium sp.

Schizochytrium sp. Extracted Lipids Prevent Alopecia by Enhancing Antioxidation and Inhibiting Ferroptosis of Dermal Papilla Cells

“…The composition of SEL was analyzed according to a previously reported method [36]. In short, 100 mg of SEL was mixed with 2 mL of 4% methanol and sulfuric acid and heated in a water bath at 65 • C for 1 h in order to obtain fatty acid methyl esters (FAMEs).…”

PUFA and carotenoid producing thraustochytrids and their anti-microbial and antioxidant activities

“…However, the DHA content of fish oil is low, and large-scale production of DHA from fish oil is difficult (Kalidasan et al, 2021b). Overfishing of fish stocks and global warming are known to decline in fish populations, causing a disruption in the DHA demand, and supply flow chain (Liang et al, 2022). In this connection, thraustochytrids have the greatest potential for fish oil replacement because they contain more DHA and EPA than fish oil (Song et al, 2015).…”

“…However, the fish oil contains a low level of DHA and large-scale production of the DHA from the fish oil is difficult (Kalidasan et al, 2021b). In the context of the over-exploitation of fish stock and declining fish populations, the DHA demand and supply flow chain are disturbed (Liang et al, 2022). The omega-3 PUFA market is valued at approximately 4.3 billion USD in 2019 (Aasen et al, 2016).…”