Lipids of oleaginous yeasts. Part II: Technology and potential applications

The process of lipid accumulation in the oleaginous yeasts cultivated in various fermentation configurations when either sugars and related compounds or hydrophobic substances are used as substrates is presented and kinetic models describing both de novo and ex novo lipid accumulation are analyzed. Technological aspects related with single cell oil (SCO) produced by oleaginous yeasts are depicted. The influence of culture parameters upon lipid production process is presented. Lipid production has been studied in batch, fed-batch, and continuous cultivation systems using yeasts belonging to the species Lipomyces starkeyi, Rhodosporidium toruloides, Apiotrichum curvatum, Candida curvata, Cryptococcus curvatus, Trichosporon fermentans, and Yarrowia lipolytica. The potentiality of yeasts to produce SCO as starting material of 2nd generation biodiesel is indicated and discussed. Of significant importance is also the utilization of yeast lipids as substitutes of high added value exotic fats (e. g., cocoa butter). Lipid produced by the various yeasts presents, in general, similar composition with that of common vegetable oils being composed of unsaturated fatty acids, whereas cocoa butter is principally composed of saturated fatty acids, consequently the various strategies that are followed in order to increase the cellular saturated fatty acid content of the yeast lipid are presented and comprehensively discussed.