Background: Omega-3 long chain polyunsaturated fatty acids (LC-PUFAs), are important constituents of human nutrition
and have key roles in maintaining health through their effects on immune system. Although marine fish are the main
dietary source of EPA and DHA, the depletion of fish stocks and pollution of the marine environment indicate an urgent
need for an alternative and sustainable source of omega-3 LC-PUFAs. Marine microorganisms are the primary producers
of omega-3 LC-PUFAs in the aquatic food chain and EPA- and DHA-rich microalgae have been demonstrated to be a
promising alternative source to fish oils.
Methods: There is increasing interest in the metabolic engineering of microalgae and genetic modification of algal strains
is considered to be one of the most promising strategies to produce new sustainable omega-3 oils. The efficient production
of high value products such as EPA and DHA from algae is expensive and significant efforts in strain development and
cultivation technologies are required to reduce the currently high production costs associated with algal biomass.
Results: This review describes the recent advances in metabolic engineering of microalgae towards optimizing the
production of omega-3 LC-PUFAs.
Conclusion: In the last few years an intense research has been performed to maximize microalgal production of omega-3
LC-PUFAs and several bottlenecks that limit the oil accumulation have been identified. By using metabolic engineering it
is possible to overcome these barriers and generate improved strains of microalgae.