Extraction of biomolecules from aqueous media using nonionic surfactants

Bernice Perez, R. Nagarajan, and W. Curtis
The Pennsylvania State University
158 Fenske Lab
University Park, PA 16802
blp117@psu.edu
(814) 863-7182


Nonionic block copolymer surfactants can be utilized as novel solvents for the recovery of water-soluble molecules. The hydrophobic-hydrophilic character of these surfactants provides the means for the extraction of molecules within a wide range of hydrophobicity. We have chosen surfactants that have a low hydrophilic character in order to avoid a high surfactant loss during the phase separation process. The phase separation process is facilitated by centrifugation at a temperature above the cloud point temperature of the surfactant solution. One of our model molecules for this technique is shikonin, a plant-derived compound that is mainly used as a pigment for food coloring and cosmetics. Shikonin, which is sparingly soluble in water, is released from plant root cultures into an aqueous media. The percent of extraction of shikonin from the media using nonionic surfactants was almost 100%. Stripping extraction with an alkaline solution is utilized for the recovery of the shikonin derivatives, which can be ionized at high pH values, from the surfactant phase. Another model molecule is the tracer dye Rhodamine WT, which is highly soluble in water. The percent of extraction of this hydrophilic molecule was approximately 98%. These results show that nonionic surfactants can be used for the extraction of water-soluble molecules in replacement of environmentally harmful solvents.