Campodónico, PaolaCalfuman, KarlaSuárez, CristianAlcázar, JacksonOlivares, Belén2026-09-082026-09-082025Paola R. Campodónico, Karla Calfuman, Cristian Suárez-Rozas, Jackson J. Alcázar, Belén Olivares, Interpretation and analysis of solvent and physico-chemical parameters of choline-amino acid deep eutectic solvents and their aqueous mixtures over the kinetic response, Journal of Molecular Liquids, Volume 439, Part A, 2025, 128862, ISSN 0167-7322, https://doi.org/10.1016/j.molliq.2025.128862. (https://hdl.handle.net/11447/11083This study underscores the pivotal role of choline-amino acid deep eutectic solvents, [ChCl][AA], in the hydrolysis reaction of p-nitrophenyl laurate (p-NPL), used here as a model reaction to evaluate solvent effects in various aqueous compositions. The [ChCl][AA] analyzed were choline methionine ([ChCl][Met]), and choline proline ([ChCl][Pro]). Hydrolysis reaction was performed both in the absence and presence of the enzyme Candida Antarctica Lipase B (CALB), allowing for detailed examination of how the reaction media influences enzymatic activity. Results indicate that varying solvent compositions significantly affect CALB’s catalytic behavior. A kinetic analysis, along with physicochemical evaluations, supports these findings. Notably, in the non-enzymatic hydrolysis, [ChCl][Met] showed a rate one order of magnitude higher than [ChCl][Pro]. The concentration of the phenolate form also increased with higher molar fractions ( χ ) of [ChCl][AA], implying direct involvement of [ChCl][AA] in phenoxide formation. Conversely, in the enzymatic reaction, [ChCl][Pro] facilitated a rate approximately 3.5 times faster than [ChCl][Met], with rates increasing as χ χ increased. This effect is attributed to the rigid structure of proline, which may induce beneficial conformational changes in CALB. Lineweaver-Burk plots revealed that optimal enzymatic performance occurred in media rich in [ChCl] [Met] ( = 0.85), suggesting that such environments impose structural constraints that stabilize CALB. This stability may arise from the formation of a solvation shell near the [ChCl][AA]. Surface tension data further suggest that at specific compositions, 3D assemblies form, mimicking pure [ChCl][AA] behavior. Overall, this study emphasizes the potential of [ChCl][AA] as green solvents in biocatalysis applications.enGreen chemistryBiocatalysisSolvent effectsHydrogen bondsAmino acidsAqueous mixturesEnzymatic hydrolysisArticlehttps://doi.org/10.1016/j.molliq.2025.128862