Extraction of natural colorants using supramolecular solvents composed of Triton X-114 and ionic liquids

Abstract

The interest for natural colorants from microbial sources has increased in the last few years. However, the extraction of these compounds from complex biomasses/matrices is still a challenge for industrial applications, mainly due to the requirements of biocompatibility, sustainability, and efficiency. With this aim, supramolecular solvents (SUPRAS) composed of nonionic polyethylene glycol tert-octylphenyl ether (TX-114) and various cationic surfactants (n-alkyl-3-methyl imidazolium bromide ([Cnmim]Br, n = 10, 12, 14, 16), and tributyl-tetradecylphosphonium chloride ([P4,4,4,14]Cl) ionic liquids (ILs) and cetyltrimethylammonium bromide (CTAB)) were here studied for the extraction of red polyketides colorants from the fermented broth of Talaromyces amestolkiae. Firstly, the influence of ILs on the SUPRAS phase behavior was determined by measuring the cloud point temperature (TCP) and coarse-grained molecular dynamic (CG-MD) simulations. The results of extraction showed that for all SUPRAS the red colorant preferentially partitioned into the surfactant-rich (bottom) phase (partition coefficients, K > 10) with the highest partition using [C14mim]Br as a co-surfactant (K = 14.69 ± 0.15). The systems studied also allowed high recovery efficiency of all mixed surfactant-based SUPRAS (>70 % of red colorant recovered in a single extraction step) with selective for the separation of the red colorant from the yellow (1.52 ± 0.04) and orange (1.62 ± 0.08) counterparts present in the fermented broth. The novel SUPRAS have demonstrated remarkable potential in extracting red colorants from fermented broth, without requiring harsh operating conditions. As such, these platforms offer an effective means of concentrating and pre-purifying the red colorants, and hold promise for application to other molecules with similar chemical properties.