Microbial oil is also called the single cell oil，is oil of carbon source, nitrogen source, supplemented by inorganic salt and lipid with some commercial which formed by yeast, mold, bacteria and algae microorganisms under certain conditions to use carbohydrates, nitrogen compounds and ordinary oil . Under the appropriate conditions，oil of some microorganisms storage accounts for more than 20% of the biomass，with the phenotypic strains is oil producing microorganisms.
The refining process of microbial oil is the same with edible vegetable oil, mainly includes the hydration degumming, alkali refining, bleaching and deodorization, etc. The analysis indicators of microbial oil after refining includes: smell and taste, color, moisture content, density, transparency, acid value, iodine value, peroxide value, composition of fatty acids and triglyceride composition, etc.
