# Nutritional and Medicinal Properties of Microbial Oil
## 5 Composition and Properties of Microbial Oil
Regarding the microbial oil composition, it was found that such oil contains palmitic and  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & & & & & & & \\ \cline{3-8}
**Fatty Acid (\%)** & _Rhodococcus_ & _Rhodococcus_ & _Y. lipolytica_ & _Y. lipolytica_ & _Trichesporon_ & _Mortierlla_ & _Schizzolchtrium_ & _Nematochloropsis_ \\ _opacus_ **PDe30** & **sp. 602** & **CB5 207S** & **W29** & **sp. F1-2** & **_allipin_** & **_cyclanic_** \\  & [68] & [69] & [70] & [71] & [72] & CCF2861 & [73] & [74] \\ \hline C14:0 & 0.9 & 3.4 & - & - & 0.4 & 0.8 & 11.2 & 5.6 \\ C15.0 & 17.8 & 6.2 & - & - & - & - & 1.6 & 0.2 \\ C15.1 & 0.9 & - & - & - & - & - & - & - \\ C16.0 & 13.2 & 30.7 & 41 & 14.3 & 18.1 & 14.5 & 26.5 & 14.1 \\ C16.1 & 4.5 & 11.3 & 34 & 20.2 & 0.8 & 0.1 & 4.5 & 33.4 \\ C17:0 & 19.1 & 10.3 & - & - & - & - & 0.4 & 0.1 \\ C17:1 & 30.4 & 11.3 & - & - & - & 5.3 & 5.6 & 1 & 0.9 \\ C18:0 & 3 & 11.9 & - & - & - & 5.3 & 5.6 & 1 & 0.9 \\ C18:1 & 8.6 & 14.9 & 16.9 & 48.4 & 59.1 & 13.7 & 4.1 & 3.2 \\ C18:2 & 1.2 & - & 7.8 & 17.1 & 13.7 & 23.8 & 0.4 & 2.4 \\ C18:3 & - & - & - & - & 1.2 & 2.3 & 0.1 & - \\ C18:3 & - & - & - & - & - & 0.5 & - & 0.1 \\ C18:3 & - & - & - & - & - & 2.5 & - & 0.6 \\ C18:3 & - & - & - & - & - & - & 0.5 & - \\ C18:3 & - & - & - & - & - & -palmitoleic acids (saturated and unsaturated fatty acids with 16 carbons), as well as oleic and linoleic acids, which are commonly present in microbial oils [70]. Interestingly, wild-type yeasts can also be a source of long-chain polyunsaturated fatty acids, such as EPA and DHA. [PERSON] et al. [76] demonstrated the ex novo microbial oil synthesis approach with the use of waste fish oil in the culture of _Y. lipolytica_ KKP 379. The yeasts selectively accumulated fatty acids from the substrate, and the biomass contained about 23% of lipids, which was the source of the docosahexaenoicenoic (C22:6), erucic (C22:1), eicosapentaenoic (C20:5), and eicosenic (C20:1) acids. In addition, taking a closer look at other yeast species, the profile of the fatty acids present in the microbial oils of these yeasts resembles known oils and fats that occur in nature, which are used in various industries. What comes to the forefront is the microbial oil of _Tricosporo oleaginous_ (syn. _Apidrichum curatum_ or _Cryptococcus curvatus_), whose composition resembles that of cocoa butter [77]. The production of cocoa-butter-like oils from yeasts has a significant advantage over cocoa butter, as it is not influenced by weather, water shortages, or climate change [78]. In recent years, there has been an increase in interest in the use of genetic engineering methods to modify various species of yeast, directing them to the production of microbial oils with a high content of selected fatty acids, such as the following: \(\gamma\)-linolenic acid by the expression of \(\triangle\)6-fatty acid desaturase gene [79]; \(\alpha\)-linolenic acid through the expression of _F. moniliforme_\(\Delta 12/\omega 3\) desaturase [80]; conjugated linoleic acids via the elimination of \(\beta\)-oxidation; the deletion of DAG acyltransferases and the overexpression of the \(\Delta 12\)-desaturase gene in _Y. lipolytica_[81]; and increased levels of \(\alpha\)-linolenic or unusual fatty acids, i.e., eicosatrienoic (C20:3) and eicosadienoic (C20:2) acids, by the transformation of _Tricosporo oleaginous_ ATCC 20,509 [82]; as well as the production of EPA- and DHA-rich oil in _Y. lipolytica_ by the expression of several desaturase and elongase genes [83; 84]. The engineered strains of _Y. lipolytica_ were also harnessed for the biosynthesis of a human milk fat substitute by [PERSON] et al. [85]. Milk fat is characterized by the presence of palmitic acid in the _sn_-2 position in the glycerol backbone.