Transferring of red Monascus pigments from nonionic surfactant to hydrophobic ionic liquid by novel microemulsion extraction

Nonionic surfactant micelle aqueous solution as well as cloud point system is a potential separation/reaction medium. Downstream processing for recovery of product and regeneration of surfactant is indispensable. Adjustment of pH in the dilute phase of cloud point extraction is a common strategy for separation of ionizable organic compound from nonionic surfactant. However, this strategy is no longer suitable for recovery of ionizable organic compound with strong hydrophobicity due to the high solubilization of the ionic state of hydrophobic organic compound in micelles. Setting extractive fermentation of intracellular Monascus pigments in nonionic surfactant micelle aqueous solution to produce high color hue of red Monascus pigments as an example, transferring of hydrophobic Monascus pigments from nonionic surfactant to ionic liquid by novel hydrophobic ionic liquid-nonionic surfactant-water Winsor I microemulsion extraction and then back-extraction of the ionizable Monascus pigments from the ionic liquid by ionic liquid-water two-phase extraction were carried out. Nearly 80% yield was achieved in the complete process for recovery of Monascus pigments. It provides a novel strategy for stripping of hydrophobic ionizable organic compound from nonionic surfactant micelle aqueous solution.