Recovery of Rhodococcus biosurfactants using methyl tertiary-butyl ether extraction

In the present study, we proposed methyl tertiary-butyl ether (MTBE) as a s olvent for extraction of biosurfactants from Rhodococcus bacterial cultures . After comparison with other well known solvent systems used for biosurfac tant extraction, it was found that MTBE was able to extract crude surfactan t material with high product recovery (10 g/l), efficiency (critical micell e concentration (CMC), 130-170 mg/l) and good functional surfactant charact eristics (surface and interfacial tensions. 29 and 0.9 mN/m, respectively). The isolated surfactant complex contained 10% polar lipids. mostly glycoli pids possessing maximal surface activity. Ultrasonic treatment of the extra ction mixture increased the proportion of polar lipids in crude extract. re sulting in increasing surfactant efficiency. Due to certain characteristics of MTBE, such as relatively low toxicity, biodegradability, ease of downst ream recovery, low flammability and explosion safety, the use of this solve nt as an extraction agent in industrial scale biosurfactant production is f easible. (C) 2001 Elsevier Science B.V. All rights reserved.