Mechanisms controlling lipid accumulation and polyunsaturated fatty acid synthesis in oleaginous fungi

Abstract

AbstractPolyunsaturated fatty acids (PUFAs) are functional lipids that have been widely incorporated into several industrial sectors. Apart from animal- and plant-derived origins, oleaginous fungi belonging to Mucorales have been identified as promising alternatives for production of n-3 and n-6 PUFAs. It was found, in Mucorales fungi, that ATP:citrate lyase, acetyl-CoA carboxylase and malic enzyme trigger lipid overproduction, and biosynthesis of PUFA requires membrane-bound desaturases with fatty acyl substrate specificities. Accumulation of PUFAs in the cells is associated not only with the desaturation system, but it is also tightly bound with acyltransferases that facilitate the distribution of newly synthesized PUFA to individual lipid structures. Several physical parameters, such as temperature, aeration, and nutrient regimes, greatly affect either the lipid content or fatty acid composition among different Mucorales species. Conclusive evidence showed that the PUFA production yield of the fungi depends on the environmental control of “oleaginous” enzymes, and on the transcriptional expression of the desaturase genes. These valuable studies provide perspectives with biological rationale for microbial production of economically important lipids.