For conventional submerged culture in an aqueous solution at
low pH, orange Monascus pigments was majorly accumulated intracellularly.
Extractive fermentation in nonionic surfactant micelle
aqueous solution under the same condition had exported the intracellular
pigments into its extracellular broth. More interestingly,
the fraction of yellow Monascus pigments increased markedly and
the yellow Monascus pigments became as the major pigment components
(Fig. S1). The extracellular broth was subjected to ionic liquid
([Bmim]PF6) based Winsor I microemulsion extraction as
depicted in Fig. 2A. High recovery yield based on absorbance at
410 nm (95.5%) and 470 nm (96.3%) was achieved, respectively.
The excess IL phase was subjected to wash with water due to the
limited solubility of IL in water [20]. The result indicated that the
loss of Monascus pigments into the Wm phase was only occurred
in the first run of Winsor I microemulsion extraction due to the solubilization
of Monascus pigments in theWm phase (Fig. 2B). The loss
of Monascus pigments became nearly negligible by further Winsor I
microemulsion extraction, which also indicated that the contaminated
nonionic surfactant in the excess IL phase was very limited
after the first run of Winsor I microemulsion extraction.