Extraction of ovalbumin with gemini surfactant reverse micelles – Effect of gemini surfactant structure

Abstract

Abstract So far, the protein with high solubility in water (such as bovine serum albumin) has been always chosen as the model protein in the studies on reverse micellar extraction; to recover the protein with considerable hydrophobicity from organic phase may not be easy. Noticing that the surfactants used have been mostly conventional ionic surfactants, in the present study, we extract ovalbumin (OVA), a typical globular protein exhibiting emulsifying and foaming capabilities and forming gels upon heating, with a series of gemini surfactant (C m - s -C m ⋅2Br with m being 12, s being 2, 8, 12 or m being 16, s being 5, 8) reverse micelles. Results show that C 12 - s -C 12 ⋅2Br reverse micelle can load more OVA than C 16 - s -C 16 ⋅2Br reverse micelle. Under optimum condition, ca. 90% of OVA can be transferred from water into all these gemini surfactant reverse micelles, while the backward extraction efficiency (i.e. the recovery of OVA from reverse micellar phase) is dependent on gemini surfactant structure; about 59–73% of OVA can be transferred back into water from C 12 -2-C 12 ⋅2Br, C 16 -5-C 16 ⋅2Br and C 16 -8-C 16 ⋅2Br reverse micelles, but very little OVA can be recovered from C 12 -8-C 12 ⋅2Br and C 12 -12-C 12 ⋅2Br reverse micelles.