Influence of chaotropes on recovery of trypsin and micellar sizes during reverse micelle extraction

• Dilute chaotropes were introduced to reverse micellar extraction system.
• Protein could be effectively released from reverse micelles with chaotrope.
• Chaotrope could influence water content and diameter of reverse micelles.
• The adjustment of micellar size can be achieved by using urea to increase and by using GuHCl to decrease.

Reverse micellar extraction is a promising technique in large-scale bioseparation. However, low recovery and high salt concentration in back extraction limit its application. In this study, some dilute chaotropes (Urea and GuHCl) were introduced to AOT/isooctane/ethanol reverse micellar system, and with this system trypsin could be effectively recovered during forward and back extraction. In forward extraction, the recovery increased obviously with the addition of 0.02 M GuHCl in aqueous phase. During back extraction, dilute chaptrope was explored to enhance the release of enzyme instead of high salts in the stripping phase. Trypsin enwrapped in reverse micelles was released effectively in the presence of dilute urea and GuHCl during back extraction. 95.0% activity recovery from crude material was obtained by adding 0.50 M urea and 0.05 M GuHCl in the stripping phase. The mechanism of chaotrope for reverse micelles was explored and it showed that the chaotrope could remarkably influence the water content and diameter of reverse micelles. In this study, both water content and diameter of reverse micelles increased gradually as urea concentration rose, whereas they decreased as GuHCl concentration rose in the stripping phase during reverse micellar extraction.