(214j) Oil Dispersion Using Hydrophobins

Molecular simulation studies were performed to explore the feasibility of using hydrophobins, a class of proteins, in the dispersion of oil. Hydrophobins are a class of proteins produced by filamentous fungi in soil. Preliminary experimental results from the Russo group with the hydrophobin Cerato ulmin (CU) suggests that these proteins can efficiently encapsulate oil and air in cylindrical structures, which implies a striking surface activity. These properties, when combined with the abundancy of these proteins, have motivated applications such as removal of diesel fuel from contaminated fresh water. Because of their ease of (biosynthetic) manufacture, it is possible to imagine stockpiling hydrophobins for potential use as ‘natural’ oil spill dispersants. However, a fundamental understanding of the interfacial properties of hydrophobins when they encapsulate oil (to form ‘blobs’) or gases (to form bubbles), is crucial to determine whether CU can be an efficient oil/gas dispersant. Here we investigated the properties of hydrophobins on air/water and oil/water interfaces using potential of mean force (PMF) calculations and classical molecular dynamics (MD) simulations, using both all-atom and coarse-grained representations. Relevant interfacial properties, such as free energies, density profiles, structure and stability of small blobs and bubbles are investigated and discussed in this study.