Lipid Production in Yeasts

Yeasts can convert sugars and other renewable substrates to lipids, which can be further processed to chemicals of higher value or via transesterification to liquid transportation fuels that are currently produced from fossil resources or plant oils [62]. 

The economic feasibility of a lipid production process is determined by the cost of the raw materials as well as the fermentation processes itself. Glucose is the most commonly employed carbon source, but substrates like xylose, lactose, mannose, glycerol, mannitol, L-arabinose, ethanol, as well as wastewaters derived from animal fat treatment and olive oil mills are considered for single-cell oil production in yeast (reviewed in [67]). 

The general ability to accumulate Upids varies between yeast species and is dependent on the substrate, nutrient hmitation, and the environmental conditions, such as pH and temperature [62]. While Lipomyces starkeyi, Rho-dosporidium toruloides, and Trichosporon cutaneum grown on glucose reach total lipid contents between 40% and 65% [68-70], Y. lipolytica accumulates only up to 20% of lipids [71]. On the other hand, lipid content of Y. lipolytica cultivated on glycerol increases to 40% [72]. For further readings, we recommend the reviews by Papanikolaou and Aggelis [73,74]. 

Genetic manipulation of oleaginous yeast will not only further improve the yields and feasibility of single-cell oil production processes but also the generation of novel lipids with high value. Often-named examples are fatty acids similar to natural products like cocoa butter or fish oil, which are becoming 

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