Electrokinetic extraction and recovery of biosurfactants using rhamnolipids as a model biosurfactant

Abstract

• Electrokinetic extraction of rhamnolipids is studied. • A rhamnolipid biosurfactant is effectively extracted. • The biosurfactant is recovered in the anode compartment. • The efficiency of extraction is dependent on the voltage applied. • The recovered biosurfactant is of high purity. An electrokinetic system was evaluated for the possibility of extracting and recovering of biosurfactants in this study. This was done in a uniquely built electrokinetic reactor with two electrode chambers and a medium chamber separated by a membrane. The voltage applied was varied from 30 V to 20 V to 10 V to evaluate the effect of the voltage used on the extraction and recovery process. The results obtained revealed that the electrokinetic system can efficiently extract and recover biosurfactants from the culture broth. The biosurfactants electromigrated towards the anode compartment where they aggregated into fine solids to allow recovery. The highest extraction and recovery of 69.33 ± 3.67 % was achieved under the highest voltage of 30 V followed by 20 V with 9.63 ± 0.4 % and 10 V with 4.98 ± 0.46 %. The biosurfactants extracted using the electrokinetic system had fewer impurities than the extract recovered by acid precipitation. However, the functional groups and retardation factors of all the extracts recovered by acid precipitation and the electrokinetic system were the same.