Surfactin Self‐Assembles into Direct and Reverse Aggregates in Equilibrium and Performs Selective Metal Cation Extraction

Abstract

On tie‐lines between water‐rich and alkane‐rich solutions, it is shown via scattering experiments that natural lipopeptide surfactin self‐assembles into direct and reverse micelles in equilibrium. Elongated direct micelles in the aqueous phase are present together with small reverse globular aggregates in the organic phase. These latter are made from hydrated surfactant without any “water pool” in the organic phase. The resulting biphasic system is used for liquid–liquid extraction of model metal cations. It is efficient with iron but not with copper or neodymium. Competitive extractions show high selectivity towards iron.

Selective encapsulation of cesium ions using the cyclic peptide moiety of surfactin: Highly efficient removal based on an aqueous giant micellar system

“…1), having a long alkyl chain of length n = 7-9, is known to act as an ionophore for mono and divalent metal cations [12][13][14]. Moreover, it is abundantly produced by microorganisms such as Bacillus subtilis and also regarded as a promising environment-friendly surfactant (often called biosurfactant) that exhibits high biodegradability, in addition to high surface activity, unique self-assembling properties, and low http://dx.doi.org/10.1016/j.colsurfb.2015.06.034 0927-7765/© 2015 Elsevier B.V. All rights reserved.…”

Multiple Roles of Biosurfactants in Biofilms

“…Surfactin a cyclic lipopeptide based antibiotic disturbs the integrity of the cytoplasmic membrane's phospholipid composition and its physical properties by three different ways [85]. These include interacting with lipid membrane as (a) Mobile cation carrier [86,87] (b) Formation of cationic channels [88,89] (c) Destruction of membrane through the detergent effect [90]. Lipopeptide type BS molecules form selective cationic channels in lipid bilayer membranes and thus are involved in the functional channel-formation of target cells [91,92].…”

Selective metal ion transport through polymer inclusion membrane containing surfactin as carrier reagents

“…Recently, surfactin (SF), a bacterial cyclic lipopeptide, with a long alkyl chain produced by Bacillus subtilis strains, gained much interest since its discovery dated back to 1968 (Scheme ). It is not only an effective environmentally friendly surfactant with high biodegradability but also a chelate with high affinity toward metal cations and could be used as a chelate for selective heavy metal cation removal by liquid–liquid phase extraction or micellar‐enhanced ultrafiltration . As far as we know, SF‐facilitated metal cation transport is rarely reported.…”