Effect of chaotropes in reverse micellar extraction of kallikrein

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 CTAB/n-octane/n-hexanol reverse micellar system, the enzyme, pancreatic kallikrein could be effectively enwrapped into reverse micelles in forward extraction, but was difficult to be released during back extraction. In this study, dilute chaotropes (urea and GuHCl) were introduced to enhance the release of enzyme instead of high salts in back extraction. Kallikrein enwrapped in reverse micelles was released effectively in the presence of dilute urea and GuHCl during back extraction. Nearly 100% activity recovery of kallikrein from commercial product was obtained by adding 0.60 M urea, and for kallikrein from crude material, the recovery increased greatly by adding 0.80 M urea and 0.08 M GuHCl in the stripping solution. The mechanism of chaotrope for enhancing the release of enzyme from micelles was explored and dynamic light scatter analysis showed that the chaotrope would influence the sizes of micelles during reverse micellar extraction.

► Low recovery in back extraction of reverse micelle limits its application.
► We found dilute chaotrope was effective in back extraction.
► Kallikrein enwrapped in micelle was released completely in the presence of dilute urea and GuHCl.
► Dynamic light scatter analysis showed that the chaotrope would influence the sizes of micelles.