surfaktin

Surfactin, also spelled surfaktin, is a cyclic lipopeptide biosurfactant produced primarily by Bacillus subtilis and related Bacillus species. It comprises a heptapeptide ring linked to a beta-hydroxy fatty acid, forming a cyclic lactone. The length of the fatty acid tail is variable, typically in the C14–C15 range, which modulates its surface activity and biological effects. Surfactin is renowned for its exceptionally strong surface activity, capable of reducing water surface tension from about 72 mN/m to the low 20s–30 mN/m range and for forming micelles at relatively low concentrations.

Biosynthesis occurs nonribosomally via the nonribosomal peptide synthetase (NRPS) system encoded by the srfA operon in Bacillus species. Production is influenced by culture conditions, including nutrients, oxygen availability, pH, and aeration, making optimization important for higher yields in industrial or research settings.

Biological activity and mechanism: surfactin exhibits antimicrobial activity against a range of bacteria and fungi, and can disrupt lipid membranes leading to cell lysis. Its membrane-active mechanism underlies both its surfactant properties and its antimicrobial effects, and it has been explored for additional bioactivities in research contexts.

Applications and limitations: as a biosurfactant, surfactin is used in environmental bioremediation, enhanced oil recovery, and as an emulsifier in some cosmetic and industrial formulations. Its use is tempered by safety considerations, as surfactin can be hemolytic and cytotoxic at higher concentrations, highlighting the importance of appropriate formulation and dosing in any application.