Oleaginous yeasts form Uruguay and Antarctica as renewable raw material for biodiesel production

In the present study a screening of oleaginous yeasts from different habitats nearby Montevideo, Uruguay, was carried out. Four yeast strains previously isolated from soil from Fildes Peninsula, in the Antarctic region, were also included in the study. More than 75% of the obtained isolates were characterized as oleaginous though only four of them (two from Antarctica and two from Uruguay) were able to accumulate lipids to levels exceeding the 40% of cell dry weight. One of the selected strains was identified as Rhodotorula graminis, which has been already recognized as an oleaginous species. However, the other three isolates belong to species, which have not been reported as oleaginous before. This work constitutes the first report of Cryptococcus phenolicus, Cystofilobasidium infirmominiatum and Leucosporidium scottii as oleaginous species. Three of the selected isolates were able to grow with glycerol as carbon source. According to lipid production in presence of glycerol, one isolate was selected for further studies. The ability to grow and accumulate intracellular lipids in presence of crude glycerol was assessed for the selected strain. In such conditions, a maximum concentration of 5.9 g L of lipids with a suitable fatty acid profile according to the requirements established in our country for the raw material used in the production of biodiesel, was obtained.