Sustainable enrichment of genipin-derived blue pigment: Recovery and purification via PEG-salt aqueous two-phase system

Aqueous two-phase systems (ATPS) are a promising approach for sustainable compound enrichment and purification. Genipin is a bioactive aglycone contained in Genipa americana which forms colored complexes after reaction with primary amines such as glucosamine (GlcN) to yield a blue chromophore complex. Since the genipin-GlcN complex exhibits low cytotoxicity (5000 - 10,000 times lower than glutaraldehyde), and displays a distinctive blue coloration, it has high potential for use as a natural colorant and bioactive compound in food, cosmetic, and pharmaceutical applications. This work provides evidence for the first time the use of an environmentally friendly aqueous two-phase system (ATPS) for the targeted separation and enrichment of the genipin-GlcN complex from genipap fruit extract. Genipa fruit extract was composed of genipin, phenolic compounds and geniposide, as it was confirmed by high performance liquid chromatography mass spectrometry (HPLC-MS). In turn, ATPS was composed of polyethylene glycol (PEG 3350, 50 % w/w) and pH 6.0 potassium phosphate salt (30 % w/w). Feed composition 5 (0.27 and 0.43 g of PEG and salt, respectively) demonstrated that the complex predominantly partitioned into the PEG-rich phase, as reflected by a partition coefficient K of 8.32 ± 0.23. Selectivity was S = 19.81 ± 0.81, with a purification factor PF of 4.52 ± 0.11 and efficiency E was 53.61 ± 0.63. These outcomes corresponded with tie-line length (TLL) of 5.15. This work provides a methodological strategy for intensification of bioprocesses, evidencing that ATPS is a feasible alternative for the recovery of complexes from non-uniform natural sample matrices.