Improved adsorptive purification and effective separation of acidic and lactonic sophorolipid biosurfactant

Abstract

Crude Sophorolipid extract obtained from fermentation broth contains both acidic and lactonic forms of Sophorolipid with different degrees of acetylation and varying lengths of the fatty acid chains. Carboxylic end in the acidic form of the fatty acid is free, whereas in the lactonic form, it is internally esterified. Sophorolipid show different physicochemical properties with wide range of applications for each structural compound. This work represents the separation and purification strategies of acidic and lactonic Sophorolipid obtained from crude extract. Depending on structure of Sophorolipid molecule different resin were selected for screening based on % binding per ml of resin, % elution and % assay purity of the product obtained.Based on binding study, uptake kinetic, adsorption isotherm and Simchrome software results, macroporous adsorbent SEPABEADS SP 825L was selected as the choice of resin for preparative separation. Breakthrough capacity of the resin was calculated to be 37.8 and 2.801 mg/mL for lactonic and acidic SL respectively. Column study was performed to justify the previous results and 10 g of crude product was processed to obtain 4.2 and 3.9 g of acidic and lactonic SL having the assay purity of more than 90%.