Long-term stable bioprocess-derived Pickering-type emulsions: Identification of key parameters for emulsion stability based on cell interaction at interface

Abstract

Industrial implementation of highly potent biphasic whole-cell biocatalytic processes is often limited due to the formation of long-term stable Pickering-type emulsions, caused by the presence of cells. State-of-the-art-concepts for phase separation fail or include inefficient and costly strategies (centrifugation/de-emulsifiers). Using the phenomenon of catastrophic phase inversion (CPI), efficient phase separation can be achieved by addition of dispersed phase. To show the industrial applicability of CPI for phase separations of bioprocess-derived Pickering-type emulsions, the mutual influence of the emulsion components and thus emulsion phase behavior and stability has to be known. Characterizing several Pickering-type emulsions (stabilized by E. coliJM101 and P. putidaKT2440 cells), the cell radius, the wettability of cells, and the interfacial tension, were identified to be the most crucial parameters. On this basis, we suggest guidelines and estimation strategies for suitable process (window) selection, assisting in the introduction of these highly potent processes into industrial applications.