Identification of a malonyl CoA‐acyl carrier protein transacylase and its regulatory role in fatty acid biosynthesis in oleaginous microalga Nannochloropsis oceanica

Abstract

Oleaginous microalgae hold great promises for biofuel production. However, commercialization of microalgal biofuels remains impracticable due to the lack of suitable industrial strains with high growth rate and lipid productivity. Engineering of metabolic pathways is a potential strategy for the improvement of microalgal strains for the production of lipids and also value-added products in microalgae. Malonyl CoA-acyl carrier protein transacylase (MCAT) has been reported to be involved in fatty acid biosynthesis. Here, we identified a putative MCAT in the oleaginous marine microalga Nannochloropsis oceanica. NoMCAT overexpressing N. oceanica showed a higher growth rate and photosynthetic efficiency. The neutral lipid content of engineered lines showed a significant increase by up to 31% compared to wild type. Gas chromatography-mass spectrometry analysis revealed that NoMCAT overexpression significantly altered the fatty acid composition. The composition of eicosapentaenoic acid (C20:5), which is a polyunsaturated fatty acid necessary for animal nutrition, increased by 8%. These results demonstrate the role of MCAT in enhancing fatty acid biosynthesis and growth in microalgae, and also provide an insight into metabolic engineering of microalgae with high industrial potential.

Sequential treatment with bicarbonate and low‐temperature to potentiate both biomass and lipid productivity in Nannochloropsis oceanica

“…(f)). Increased EPA content was in accordance with the reduced arachidonic acid (ARA, C20:4) . As shown in Fig.…”

“…Furthermore, growth analysis revealed that cellular growth was not impaired during the fortification of carbonate sources as reported in other heterokont species, which implied the effective uptake of bicarbonate by N. oceanica . Increased oleaginous biomass along with the enhancement of desired products have been considered a key parameter in achieving economically viable biofuel production . Thus, we determined the cellular biomass of the treated cells.…”

“…Increased EPA content was in accordance with the reduced arachidonic acid (ARA, C20:4). 17 As shown in Fig. 4(a), low-temperature treatment significantly altered the fatty acid profile of the total lipids, particularly total saturated fatty acid content was reduced significantly in the N0T16 and N1T16 cells than that of control.…”

“…23 Increased oleaginous biomass along with the enhancement of desired products have been considered a key parameter in achieving economically viable biofuel production. 12,17 Thus, we determined the cellular biomass of the treated cells. The results showed that N1T25 and N2T25 resulted in increased cellular biomass, which was in accordance with previous reports.…”

Plastidial and ER Triacylglycerol Biosynthesis in a Growth Phase-Dependent Manner in the Heterokont Nannochloropsis oceanica

“…Overexpression of plastidial ACCase resulted in significant elevation of fatty acid and lipid content in P. tricornutum . Similarly, overexpression of MCAT resulted in the remarkable elevation of fatty acids and lipids by providing adequate fatty acid precursors for lipogenesis in Nannochloropsis (Chen et al, 2017). KAS, KAR, and ENR have also been shown to play a role in lipid metabolism in various organisms (Ajjawi et al, 2017).…”