Oleaginous yeasts have the ability to accumulate and store triacylglycerides (TAGs) to more than 20% of their cell mass. Oleaginous yeasts have advantages over oil seed plants and microalgae because they grow much faster (doubling time is usually less than an hour), accumulate cell mass to much higher densities, and are less affected by seasonal or weather conditions. The TAGs synthesized by oleaginous yeasts are often rich in polyunsaturated fatty acids and can be used either for biodiesel production or as edible oils. "Red" yeasts are oleaginous yeasts that can synthesize and accumulate high concentrations of TAGs. Many factors affect the growth of red yeasts and subsequent yields of TAGs. These factors include carbon and nitrogen sources, their concentrations, the C/N ratio, temperature, pH, aeration rate, mineral elements, inorganic salts, and inhibitors. The effect of each factor varies with the yeast strain and its growth phase. Rhodosporidium diobovatum is a "red" yeast that can utilize low-cost substrates, such as waste glycerol derived from biodiesel production as a carbon source, and can synthesize and accumulate high concentrations of both TAGs and carotenoids.