Emulsification activity was identified in the culture medium of a Brazilian wild strain of Yarrowia lipolytica IMUFRJ50682 isolated from Guanabara Bay in Rio de Janeiro. The bioemulsifier, secreted during growth in glucose as carbon source, was successfully isolated and characterized. The isolated emulsifier, named Yansan, is different from previous emulsifiers identified for Y lipolytica. It presents high emulsification activity and stability in the pH range of 3.0-9.0 and is capable of stabilizing oil-in-water emulsions with several aliphatic and aromatic hydrocarbons. (c) 2006 Elsevier Ltd. All rights reserved.