Objective: To increase the commercial value of oleaginous fungus Mortierella alpina by incorporation of trans-10,cis-12 conjugated linoleic acid (CLA) into the polyunsaturated fatty acids (PUFAs) of M. alpina via Propionibacterium acnes isomerase (PAI) conversion.
Results: The PAI gene and the codon optimization version were heterologously expressed in M. alpina via Agrobacterium tumefaciens-mediated transformation (ATMT). Coding usage modification significantly improved the translation of PAI transcripts and trans-10,cis-12 CLA was produced up to 1.2 mg l(-1), which corresponds to approx. 0.05% of the total fatty acid (TFA). Since PAI prefers free linoleic acid as a substrate rather than any other forms, 5 μM long-chain acyl CoA synthetase inhibitor was added and the trans-10,cis-12 CLA content increased approx. 24-fold to 29 mg l(-1), reaching up to 1.2% (w/w) of the TFA in M. alpina.
Conclusion: Heterologous expression of PAI in M. alpina by ATMT methods is a practicable way in biosynthesis of CLA and this system may be a feasible platform for industrial production of CLA.
Keywords: Conjugated linoleic acid; Heterologous expression; Linoleic acid isomerase: Mortierella alpine; Trans-10,cis-12CLA; Triacsin.