Production and Toxicity Assessment of Sophorosides from Torulopsis bombicola

Production of sophorosides from Torulopsis bombicola cultivated on three different substrates (methyl oleate, olive oil, and rapeseed oil) was studied. The higher yield (60-70%) was obtained with olive oil, which also corresponds to the less expensive lipid source. Sophorosides did not show great antifungal and antibacterial activities except against Candida parapsilosis and Staphylococcus aureus. Other tested microorganisms were resistant to and sometimes stimulated by these compounds. Cytotoxicity of sophorosides on cultured human fibroblasts (human skin or MRC5 line) was almost the same as with cholesterol acetate but higher than with DL-alpha-lecithin. Moreover, on skin fibroblasts LC50 was near LC100 with sophorosides, indicating the possibility of acute toxicity in some cases