Long-Chain Alcohol-Modified Micellar Systems and Their Application in a Continuous Extraction Process

Abstract

The integration of an in situ extraction into biocatalytic processes is often limited by the toxicity of organic solvents. Therefore, it is desirable to use water-based extraction systems (for example, aqueous micellar two-phase systems). They can be used, for instance, for the extraction of valuable products from microalgae cultures. Recently, the nonionic surfactant ROKAnol\u202fNL5 was identified as a suitable surfactant for this purpose, since it forms an upper micellar phase, enabling an easy separation of whole-cell biocatalysts. However, its application at temperatures below 45 °C is limited by unstable phase boundaries, whereas the maximal temperature to ensure the vitality of the most microalgae cultures is ∼40 °C. To overcome this problem, the addition of long-chain alcohols to the surfactant–water mixture during extraction is suggested in this work. Using 1-hexanol, a continuous extraction process with the model solute trans-cinnamic acid at 40 °C in a stirred column could be realized. The results o...