Downstream processing of Class II hydrophobins for the production of stable hydrophobin powders

Hydrophobins (HFBs) are cysteine-rich, low molecular weight proteins produced by some filamentous fungi. HFBs are considered as the strongest surface active proteins from microbial origin and exhibit unique physicochemical properties. For example, hydrophobins can change the polarity of surfaces. They self-assemble at hydrophobic-hydrophilic interfaces forming an amphiphilic membrane and reduce the surface tension of water. Hydrophobins are divided in two classes, namely Class I and Class II hydrophobins. Class II hydrophobins exhibit a strong elasticity in addition to their surface active properties. Therefore, Class II HFB are considered to be of great value in different industrial sectors such as food, pharmaceutical and cosmetics industry. However, industrial applications with hydrophobins are not available to date due to insufficient production quantities and lack of methods to obtain a stable product. Therefore, the main objective of this doctoral research is to develop and optimize a simple and efficient method to purify Class II hydrophobins as well as a drying method to produce highly stable hydrophobin powders.