Metabolic engineering for the production of omega-3 fatty acids, the clinically important molecules for nutrition and health

Abstract

EPA and DHA that are omega-3 long chain-polyunsaturated fatty acids (LCPUFA)

are referred to as 21st century’s miracle food due to their beneficial roles

in the pharmaceutical and nutrition industries. EPA and DHA have a positive

effect on the cardiovascular system and intellectual development. Therefore,

there is increasing demand for these omega-3 LC-PUFA. However, since the

most common commercial source for EPA and DHA is limited to ocean fish,

increasing world population and overfishing curbs their supply. Microbial

production of EPA and DHA incorporated with a metabolic engineering approach

presents a feasible solution to commercially produce these omega-3 LC-PUFA.

In microbes, synthesis of LC-PUFA can proceed via the aerobic pathway

involving desaturases and elongases or the anaerobic pathway involving

polyketide synthases. Yarrowia lipolytica, a yeast, exhibits high lipid

accumulation when nutrient deprived under aerobic conditions. Shewanella

baltica, a marine bacterium, synthesizes PUFA during cold temperatures under

anaerobic conditions as a mechanism to regulate its membrane fluidity.

Therefore, Yarrowia lipolytica and Shewanella baltica serve as suitable microbial

hosts for the production of EPA and DHA through genetic engineering strategies .