Marine fungoid producers of DHA, EPA and carotenoids from central and southern Chilean marine ecosystems

Abstract

Declining fishing yields have pushed the search for sustainable alternative sources for polyunsatura ted fatty acids (PUFAs). Thraustochytri ds and marine yeasts (mari ne fungoid protists) are potenti al commercial sources of li pi ds and car otenoids. It was determined the capacity of a collection of 41 str ains of marine fungoid isol ated in the H umboldt Current System, to produce DHA (docosahexanoic acid), EPA (eicosapentanoic acid) and CT (total carot enoids) in commercial growing media (MS) and alternative growing mediums (PDB, GAM, BAM and MCM). The media MS and PDB exh ibited the highest growth rate (0.02 h-1 ), at 16 and 37°C, respectively. Thirteen of the studied strains showed high capacity to produce DHA (up to 23% dry weight) and CT (up to 18% dry weight), comparable to levels observed in Schizochytrium sp. KH105 and Rhodosporidium toruloides. Additionally, all studied strains produce small amounts of EPA (up to 0.3% of dry weight). Scannin g electron microscopy reveals that strain C36 is morphologically consistent with yeasts, while partial sequencing of the 18s ribosomal gene shows 97% similarity to the genus Rhodotorula , which has not been reported until now as a producer of DHA and EPA. Finally, the strains C36, C22 and C4 offer promising potential for upscaling their prod uction for commercial use for enriching human food and animal and larval fish feed with omega-3 and carotenoids, as well a s being a source for food dyes for salmon and other products