Improvement of Sporobolomyces ruberrimus carotenoids production by the use of raw glycerol

The red yeast Sporobolomyces ruberrimus H110 was able to use glycerol as a carbon source. The highest concentration (0.51 g L−1) and productivity (0.0064 g L−1 h−1) of carotenoids were achieved when raw glycerol from biodiesel production, containing around 1 g L−1 of fatty acids, was used as the carbon source, which represented increases of 27% and 1.5×, respectively, in relation to pure glycerol. Mass spectrometry analysis led to the identification of four carotenoids in the fermented samples, torularhodin, torulene, β-carotene and γ-carotene. The use of raw glycerol also enhanced the proportion of torularhodin (69% against 59% in pure glycerol). The addition of individual fatty acids (palmitic, stearic, oleic and linoleic acids) to pure glycerol resulted in increases between 15% and 25% in maximum concentration and between 1.6× and 2.0× in productivity of carotenoids. The presence of palmitic and oleic acids increased the torularhodin proportion to 66%.