A metabolic engineering strategy for producing conjugated linoleic acids using the oleaginous yeast Yarrowia lipolytica

• Published in: Applied microbiology and biotechnology 2017-06, Vol.101 (11), p.4605-4616
• Main Authors: Imatoukene, Nabila, Verbeke, Jonathan, Beopoulos, Athanasios, Idrissi Taghki, Abdelghani, Thomasset, Brigitte, Sarde, Claude-Olivier, Nonus, Maurice, Nicaud, Jean-Marc
• Format: Article
• Language: English
• Subjects: Applied Genetics and Molecular Biotechnology; beta oxidation; Bioconversion; Biodegradation; Biomedical and Life Sciences; Bioreactors; Biosynthesis; Biotechnology; biotransformation; Cassettes; conjugated linoleic acid; culture flasks; Desaturase; Dietary supplements; fatty acid composition; Fatty Acid Desaturases - genetics; Fatty Acid Desaturases - metabolism; Fatty acids; Fermentation; Flasks; Fungal Proteins - genetics; Fungal Proteins - metabolism; gene overexpression; genes; Genetic engineering; Genetic modification; Genetically modified organisms; Health aspects; human health; Humans; Isomerases - genetics; Isomerases - metabolism; Life Sciences; Linoleic acid; Linoleic Acids, Conjugated - biosynthesis; Lipids; Lipids - biosynthesis; Metabolic engineering; Metabolic Engineering - methods; Microbial Genetics and Genomics; Microbiology; Microbiology and Parasitology; Microorganisms; mutants; Mycology; Oxidation; Oxidation-Reduction; Promoter Regions, Genetic; Propionibacterium acnes; Propionibacterium acnes - enzymology; Propionibacterium acnes - genetics; triacylglycerols; Triglycerides; Unsaturated fatty acids; Yarrowia - genetics; Yarrowia - metabolism; Yarrowia lipolytica; Yeast; Yeasts
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-017-8240-6

Conjugated linoleic acids (CLAs) have been found to have beneficial effects on human health when used as dietary supplements. However, their availability is limited because pure, chemistry-based production is expensive, and biology-based fermentation methods can only create small quantities. In an effort to enhance microbial production of CLAs, four genetically modified strains of the oleaginous yeast Yarrowia lipolytica were generated. These mutants presented various genetic modifications, including the elimination of β-oxidation ( pox1 - 6 ∆), the inability to store lipids as triglycerides ( dga1 ∆ dga2 ∆ are1 ∆ lro1 ∆ ) , and the overexpression of the Y. lipolytica ∆12-desaturase gene (Yl FAD2 ) under the control of the constitutive p TEF promoter. All strains received two copies of the p TEF - oPAI or p POX - oPAI expression cassettes; PAI encodes linoleic acid isomerase in Propionibacterium acnes . The strains were cultured in neosynthesis or bioconversion medium in flasks or a bioreactor. The strain combining the three modifications mentioned above showed the best results: when it was grown in neosynthesis medium in a flask, CLAs represented 6.5% of total fatty acids and in bioconversion medium in a bioreactor, and CLA content reached 302 mg/L. In a previous study, a CLA degradation rate of 117 mg/L/h was observed in bioconversion medium. Here, by eliminating β-oxidation, we achieved a much lower rate of 1.8 mg/L/h.