Efficient co-production of EPA and DHA by Schizochytrium sp. via regulation of the polyketide synthase pathway

Abstract

Presently, the supply of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) traditionally produced by marine fisheries will be insufficient to meet their market demand in food industry. Thus a sustainable alternative source is urgently required. Schizochytrium sp. is an ideal producer of DHA; however, its ability to co-produce DHA and EPA has not yet been proved. Herein, we first described a cobalamin-independent methionine synthase-like (MetE-like) complex, which contains independent acyltransferase and 3-ketoacyl synthase domains, independent of the traditional polyketide synthase (PKS) system. When the MetE-like complex was activated, the EPA content was increased from 1.26% to 7.63%, which is 6.06-folds higher than that in the inactivated condition. Through lipidomics, we find that EPA is more inclined to be stored as triglyceride. Finally, the EPA production was enhanced from 4.19 to 29.83 (mg/g cell dry weight) using mixed carbon sources, and the final yield reached 2.25 g/L EPA and 9.59 g/L DHA, which means that Schizochytrium sp. has great market potential for co-production of EPA and DHA.

Efficient Biosynthesis of Odd-Chain Fatty Acids via Regulating the Supply and Consumption of Propionyl-CoA in Schizochytrium sp

“…31 In our previous study, it has been shown that the METE gene in Schizochytrium sp. is incomplete, 32 which may be the direct cause of the significant decrease in growth and lipid accumulation under the B 12 − condition. Therefore, the B 12 − condition can inhibit propionyl-CoA consumption and thus promote OCFA accumulation, but growth limitation needs to be addressed.…”

Transcriptome Analysis Reveals an Eicosapentaenoic Acid Accumulation Mechanism in a Schizochytrium sp. Mutant

“…At the same time, the production performance of DBT-64 in the fed-batch fermentation process is second only to that described in Wang et al ( 47 ), but it still has an advantage in the proportion of EPA. In a recent study, Ma et al achieved an EPA yield of 2.25 g/L through a cobalamin-deficient fermentation process ( 48 ), which may provide a new idea for our future work.…”

Lipidomic and transcriptomic analysis of the increase in eicosapentaenoic acid under cobalamin deficiency of Schizochytrium sp

“…The biomass, glucose, and total lipid measurements were conducted using the same methods in our previous study. [ 19 ] At various time points, fresh cells were collected via centrifugation at 12000 g for 2 min. The supernatant was then diluted 100 times, and glucose concentration was determined using a bioanalyzer (SBA‐40ES, YanHe Biotechnology, China).…”