Microbial carotenoids extraction using aqueous solutions of cholinium-based ionic liquids

A more sustainable, low-cost and biocompatible method for carotenoids extraction from yeast Rhodotorula glutinis using ionic liquids (ILs) was designed in this work. It was evaluated the aptitude of 4 cholinium-based ILs as a substitute of volatile organic compounds (VOCs) in this Solid-Liquid Extraction (SLE). The processing procedure of the proposed SLE with ILs was compared with the conventional SLE using Dimethyl sulfoxide (DMSO), as solvent. The highest extraction yield was obtained with an SLE using concentrated hexanoate-based IL (90% v/v), at 0.2 g/mL of wet biomass, in 1 hour, 150 rpm and 25 °C, where 116.79 µg/mL of β-carotene yield, 110.15 µg/mL of Torularhodin and 14.81 µg/mL of Torulene were recovered. SLE using DMSO as solvent, under same processual conditions, only recovered 30.15 µg/mL of β-carotene, 36.13 µg/mL of Torularhodin and 3.30 µg/mL of Torulene. Overall, the results demonstrate that hexanoate-based ionic liquids can recover up to 4-fold more carotenoids than the conventional VOCs, proving that the use of “greener” solvents as cell disrupting agents can be a simple, efficient and feasible method to recover intracellular carotenoids.