Imidazolium-based ionic liquids as co-surfactants in aqueous micellar two-phase systems composed of nonionic surfactants and their aptitude for recovery of natural colorants from fermented broth

Abstract

Over the last few years, synthetic colorants have been increasingly replaced by natural alternatives that cause fewer adverse health effects and can show biological activity. These biocompounds can be produced by fermentative processes using microorganisms such as bacteria and filamentous fungi. However, the biocompounds must be extracted from the fermented broth before industrial application. Thus, the development of effective techniques for the extraction and purification of biocolorants with high recovery is of great interest. The main goal of this study was to evaluate the recovery of natural colorants produced by Talaromyces amestolkiae using aqueous micellar two-phase system (AMTPS) composed of Triton X-114 and Ionic Liquids (ILs) from the imidazolium family as co-surfactants. Preliminary experiments were performed to determine the binodal curves in both presence and absence of fermented broth containing the red colorants. Subsequently, a set of partitioning experiments was performed using the developed systems. Under all conditions, the red colorants were partitioned mainly into the micelle-rich phase. The systems with low concentrations of Triton X-114 and ILs showed high partition coefficients. The system (0.1 wt% [C10mim]Cl + 3 wt% Triton X-114) with the highest partition coefficient (KRC = 6.12) was used to study the effect of temperature on partitioning. The partitioning of the red colorants was strongly influenced by the temperature, and KRC increased to 24.71 at 45 °C. The results of this study demonstrate that the partitioning of biomolecules can be controlled by the presence of ILs, mainly by electrostatic interactions, or by the proper adjustment of the partitioning temperature.