LAUSR

ABSTRACT In oil and petroleum industries, emulsification process is important to transfer and upgrade heavy oil. Rhamnolipids are the essential molecules of biosurfactants that used for this goal and they are often produced from various types of Pseudomonas aeroginosa bacteria. In this research, rhamnolipid biosurfactant produced from Pseudomonas aeroginosa ATCC 9027. The goal of this study was to optimize the effective parameters in production of rhamnolipid in order to reach the minimum water droplet size using Taguchi method. The evaluated parameters include incubation temperature, RPM of incubation, C/N ratio and pH of aqueous phase. Response parameters were yield, cost and water droplet size in water in oil (w/o) microemulsion. The results illustrated that the temperature of incubation and pH of the aqueous phase were the most effective factors in the production of rhamnolipid. Optimum operation condition including yield, cost and water droplet size, were 5.2 ± 0.1 g/l, 2.4 ± 0.14 $/g and 70 ± 5%, respectively. Dynamic light scattering (DLS) analysis was used for determination of water droplet size. Also the emulsification index (E24) of (w/o) emulsion was 98% ± 4. The results of this study could reduce the cost of rhamnolipid production for the applications in oil industries.