Evaluation of a co-product of biodiesel production as carbon source in the production of biosurfactant by P. aeruginosa MSIC02
Abstract This work focuses on the use of a co-product of biodiesel production as carbon and energy source for the production of rhamnolipids by a new strain of Pseudomonas aeruginosa MSIC02. Different carbon sources were compared and the highest rhamnolipid concentration (1269.79 mg/L) was achieved when hydrolyzed glycerin was used. The study of nutritional and environmental conditions allowed an increase in the production of rhamnolipids. Maximum rhamnolipid concentration was attained at 18 g/L of glycerol, 4.0 g/L of NaNO 3 , 62 mM of KH 2 PO 4 , pH 7.0 and 37 °C. Highest product yields on substrate and biomass and productivity were achieved at the same conditions. The biosurfactant showed good emulsifying properties (IE 24  = 65%), being able to form emulsions with mineral and vegetable oils. The NMR spectrum of H 1 and C 13 and mass spectra indicates that the purified product contained two types of rhamnolipids: l -rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate (RL1) and l -rhamnosyl l -rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate (RL2).