Effect of beta-cyclodextrin in artificial chaperones assisted foam fractionation of cellulase

Foam fractionation has the potential to be a low-cost protein separation process; however, it may cause protein denaturation during the foaming process. In previous work with cellulase, artificial chaperones were integrated into the foam fractionation process in order to reduce the loss of enzymatic activity. In this study, other factors were introduced to further reduce the loss of cellulase activity: type of cyclodextrin, cyclodextrin concentration, dilution ratio cyclodextrin to the foamate and holding time. alpha-Cyclodextrin was almost as effective as beta-cyclodextrin in refolding the foamed cellulase-Cetyltrimethylammonium bromide mixture. beta-Cyclodextrin (6.5 mM) was almost as effective as 13 mM beta-cyclodextrin in refolding. The dilution ratio, seven parts foamate and three parts beta-cyclodextrin solution, was found to be most effective among the three ratios tested (7:3, 1:1, and 3:7). The activity after refolding at this dilution ratio is around 0.14 unit/mL. The refolding time study showed that the refolding process was found to be most effective for the short refolding times (within 1 h).