Abstract: A Brazilian strain of Penicillium citrinum produced a lipopolysaccharide with emulsifier properties during cultivation on mineral medium, containing ammonium sulfate as nitrogen source, with 1% (v/v) olive oil as the carbon source. The maximal emulsifier production (1.6 U mL-1) was obtained after 60 h of cultivation and the biomass reached 7.5 g L-1 at the end of fermentation. The production yield i.e. the amount the carbon source utilized for product synthesis was 54% and the best emulsifying activity was observed for xylene and diesel oil when compared to other carbohydrates tested. The emulsifier was shown to be stable to a wide range of pH and temperature values and was shown to contain D-galactose, D-glucose and D-xylose (8.2:1.0:5.3) with a total carbohydrate content of 43%. The presence of salts stimulated the emulsification activity, suggesting potential for its application in industrial waste or marine remediation.