A Critical Analysis of Lactococcus lactis as a Platform for the Biotechnological Production of Omega-3 Fatty Acids

Abstract

Omega-3 supplements have become increasingly popular in recent years. These supplements have been recognised for their plethora of beneficial effects ranging from disease prevention, contribution to human growth and development, and the positive modulation of host metabolism. The two most consumed forms eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been recognised as essential for good health. However, traditional supplements are commonly sourced through the coastal fishing. In combination with the growing demand and rise of global population this practice is becoming increasingly unsustainable and therefore alternative sources should be investigated. In this study, the gram-positive lactic acid bacteria (LAB), L. lactis, was assessed for its feasibility to produce long chain polyunsaturated fatty acids (LC-PUFA’s). The bioinformatics analyses identified typical components of the fatty acid synthase type II (FASII) cycle however no genes encoding position-dependent fatty acid desaturase or elongase enzymes were identified. To further assess the lipid profile of L. lactis and the effects of lipid supplementation, the bacteria was grown in TYG media with or without the supplementation of Triton X-100 and oleic acid. The GC-MS analysis revealed that L. lactis was capable of producing omega fatty acids, namely C16:1n7, C18:1n7 and C18:1n9.

However, no chain longer than C18 was produced. It was also observed that in response to supplementation L. lactis accumulated significant proportions of oleic acid when compared to the control group. The results of the lipidomic analysis were then used to design genetic cassettes which utilised algal fatty acid desaturase and elongase genes which would be capable of catalysing the production of EPA and DHA from C18:1n9 in L. lactis.

Additionally, the feasibility of the industrial utilisation of the GMO in a probiotic/postbiotic supplement and for the valorisation of low-cost lipids into LC-PUFA’s was discussed.