Surfactin is a natural cyclic lipopeptide produced by Bacillus Subtilis strains. It is one of the most effective biosurfactants and has strong detergency power. It is also a good candidate for environmental applications, such as remediation of water or soils, owing to its efficient removal power of hydrocarbons or heavy metals.

Christophe Déjugnat and co-workers, Université Paul Sabatier, Toulouse, France, have show that surfactin self-assembles at low concentrations to form both reverse and direct micelles. This ability arises from its conformational flexibility and results in both types of micelles being present in equilibrium in biphasic systems.

The resulting biphasic system was used for the liquid–liquid extraction of metal cations mimicking those in spent nuclear fuel. Surfactin enabled the stoichiometric and selective extraction of ferric cations from the mixture of Nd³⁺, Fe³⁺, and Cu³⁺.

If the high cost and vulnerability to extreme conditions can be overcome, surfactin or a related protein could become a green way of recycling nuclear fuel.

• Surfactin Self-Assembles into Direct and Reverse Aggregates in Equilibrium and Performs Selective Metal Cation Extraction
  C. Déjugnat, O. Diat, T. Zemb,
  ChemPhysChem 2011.
  DOI: 10.1002/cphc.201100094