Photo-autotrophic, mixotrophic and heterotrophic production of essential long chain polyunsaturated fatty acids in photosynthetic and non-photosynthetic microorganisms: a review
Abstract
Some photosynthetic and non-photosynthetic microorganisms such as microalgae, stramenopiles or fungi, are known as natural producers of long chain polyunsaturated fatty acids (LC-PUFAs). Among those, some species are known as obligate heterotrophs, mixotrophs or obligate phototrophs. However, more and more microalgal species, previously reported as obligate photo-autotrophs, are now identified as mixotrophs or heterotrophs. The biosynthetic pathways and cultivation conditions of these microorganisms are compared to highlight the factors influencing production and distribution of LC-PUFAs in the cells. LC-PUFA production has been improved by the choice of cultivation processes and microorganism strains. Analyses of the conversion yields and productivities of LC-PUFAs in photo-autotrophic, mixotrophic and heterotrophic cultivation elucidate the performance of LC-PUFA production by photosynthetic and non-photosynthetic organisms.