Hydrophobin purification based on the theory of CO2-nanobubbles

Abstract

ABSTRACTPurification is a critical step to obtain hydrophobin HFBII for use in positive applications. In this study, hydrophobin HFBII was produced by Trichoderma reesei via submerged fermentation. Using the CO2-foam fractionation method yielded a fourfold increase in protein concentration. The foamate (αL-HFBII) was dried using a nano spray-dryer under optimal temperature. The gushing activity of the dried foamate (αS-HFBII) decreased. Addition of Tween 80 to the foamate before the drying process partially prevented the deactivation of hydrophobin HFBII. The purity of the powder was enhanced based on the theory of CO2-nanobubbles in a CO2-rich environment. The collected CO2-nanobubbles were added to an apolar–polar system and the interface of these two phases was collected. After evaporation of the apolar phase, the purity of the hydrophobins assembled on the surface of the liquid was significantly improved.