Browsing by Author "Gajardo-Parra, Nicolás F."

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    Assessing the Effect of Deep Eutectic Solvents on α-Chymotrypsin Thermal Stability and Activity
    (2024) Gajardo-Parra, Nicolás F.; Cea-Klapp, Esteban; Chandra, Anshu; Canales Muñoz, Roberto; Garrido, José Matías; Held, Christoph; Guajardo Ramírez, Nadia Verónica
    Optimizing the liquid reaction phase holds significant potential for enhancing the efficiency of biocatalytic processes since it determines reaction equilibrium and kinetics. This study investigates the influence of the addition of deep eutectic solvents on the stability and activity of α-chymotrypsin, a proteolytic enzyme with industrial relevance. Deep eutectic solvents, composed of choline chloride or betaine mixed with glycerol or sorbitol, were added in the reaction phase at various concentrations. Experimental techniques, including kinetic and fluorometry, were employed to assess the α-chymotrypsin activity, thermal stability, and unfolding reversibility. Atomistic molecular dynamics simulations were also conducted to assess the interactions and provide molecular-level insights between α-chymotrypsin and the solvent. The results showed that among all studied mixtures, adding choline chloride + sorbitol improved thermal stability up to 18 °C and reaction kinetic efficiency up to two-fold upon adding choline chloride + glycerol. Notably, the choline chloride + sorbitol system exhibited the most substantial stabilization effect, attributed to the surface preferential accumulation of sorbitol, as corroborated by the computational analyses. This work highlights the potential of tailoring liquid reaction phase of α-chymotrypsin catalyzed reaction using neoteric solvents such as deep eutectic solvents to enhance α-chymotrypsin performance and stability in industrial applications.
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    Assessing Thermodynamics Models for Phase Equilibria and Interfacial Properties Relevant to the Hydrogenation of Carbon Dioxide
    (American Chemical Society, 2024) Cea-Klapp, Esteban; González-Barramuño, Bastián; Gajardo-Parra, Nicolás F.; Karelovic, Alejandro; Quinteros-Lama, Héctor; Canales, Roberto I.; Garrido, José Matías
    © 2024 American Chemical Society.The catalytic hydrogenation of carbon dioxide has become a novel technology of economic and environmental interest that allows the production of value-added products as energy alternatives to the current demand. As product distributions are highly dependent on process conditions such as reaction temperature, pressure, and H2/CO2 ratio, it is necessary to have reliable thermodynamic models that can characterize mixtures of reactants with products over a wide range of conditions. In this contribution, the accuracy of two hydrogen models applied through equations of state (EOS) framed within variations of the statistical associating fluid theory (SAFT) is compared. These models include perturbed-chain SAFT (PC-SAFT) EOS and SAFT of variable range and Mie potential (SAFT-VR Mie) EOS. This is accomplished by the depiction of the thermodynamic behavior of mixtures of hydrogen in the context of the hydrogenation of carbon dioxide, estimating the thermodynamic behavior of the relevant mixtures. In all of the cases, zero values for the binary adjustable parameters have been implemented, and both models of hydrogen were fitted from a hydrogen+decane mixture. Available experimental data of high-pressure phase equilibria, critical loci, and interfacial tensions is used to determine the accuracy of the hydrogen models by contrasting their respective predictive capabilities, determining that the overall performance of the one applied in the SAFT-VR Mie EOS is inferior compared to the PC-SAFT one. The average absolute deviations between model calculations and experimental data for vapor-liquid equilibrium are 35.8 % (pressure), 3.10 % (liquid composition), and 2.60 % (vapor composition) for PC-SAFT, and 26.3, 3.27, and 2.65% for SAFT-VR Mie, respectively.