A designed biosurfactant for reversible emulsification of crude oil

PETR 159

Annette F. Dexter, a.dexter@uq.edu.au, Andrew S. Malcolm, s4091181@student.uq.edu.au, and Anton PJ. Middelberg, a.middelberg@uq.edu.au. Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia QLD 4072, Australia
We have developed a stimuli-responsive biosurfactant capable of acting as a reversible emulsifier for the oil industry. The surfactant, AM1, is a linear peptide capable of being biologically produced using conventional technology, as well as biodegraded in a similar manner to proteins. In the presence of divalent metal ions, the peptide self-assembles to form a cohesive film at oil-water or air-water interfaces. The interfacial film inhibits the coalescence of oil or air phases dispersed in water, allowing AM1 in the presence of metal ions to act as an effective emulsifying or foaming agent. Disruption of peptide-metal interactions by acidification of a pre-formed emulsion or foam, or addition of a metal chelating agent, leads to coalescence. A peptide-stabilized emulsion of a heavy sour crude could be phase-separated on a time scale of seconds by the addition of acid.