Salt‐Free Aqueous Extraction of a Cell‐Bound Biosurfactant: a Kinetic Study

Abstract

Abstract A cell‐bound biosurfactant produced by Lactobacillus pentosus was obtained under eco‐friendly conditions and used directly as an emulsifying agent in order to stabilize fluorene/water emulsions. The biosurfactant was extracted from L. pentosus cells with an aqueous phosphate buffer solution in the absence of NaCl. This is important because most the cell‐bound biosurfactants are extracted in the presence of NaCl, which is considered highly phytotoxic. A pseudo‐second order kinetic model best described the batch extraction of the biosurfactant from cells. As expected, the initial extraction rate of the biosurfactant increased with the temperature. Calculation of the activation energy with the Arrhenius equation yielded a positive value, indicating that the process is endothermic. The aqueous solution containing the biosurfactant was able to stabilize fluorene/water emulsions, with relative emulsion values of 62.2 % after 7 days of emulsion formation.