Publisher Summary This chapter determines the growth conditions for C. antarctica in the fermentor as well as their effect on the yield of biosynthesis and properties of mannosylerythritol lipids (MELs). During the synthesis of surface-active substances, oxygenation is of great importance because it influences the growth conditions of microorganisms hence yield of surfactant synthesis. Moreover, intensive aeration of cultivation medium, which has a low surface tension, causes an intensive foaming of the medium. It is important problem in the process. Based on the studies, it was found that the rate of airflow through the medium was a critical variable that influenced the intensity of foaming of the medium and yield of biosurfactant synthesis. However, the same intensity of medium oxygenation (50%) could be achieved, by maintaining the airflow rate at the level one or two vvm, using the so-called active regulation of stirrer revolutions. It is found that the greatest yields of glycolipids synthesis could be obtained at the airflow rate of one wm independent from carbon source, although, at the airflow rate two vvm, relatively slightly greater yield of biosurfactant was obtained in the medium with glucose.