Enzymatic reactions in supercritical CO2: carboxylation, asymmetric reduction and esterification

Selected chiral alcohols: Enzymic resolution and reduction of convenient substrates

“…The beneficial effects of SC-CO 2 for lipase-mediated reactions using either flow-type or batch-type reactors have been demonstrated by Matsuda et al [37] (Fig. 3).…”

“…When required or helpful for improving its properties, it can be mixed with different modifiers, co-solvents usually miscible with water. In turn, it differs from ordinary organic solvents by having a combination of gas-like properties (e.g., low viscosity and high diffusivity), and liquid-like properties (e.g., solubilizing power) [37]. These properties can be further modified by changing pressure and/or temperature, and by addition of a modifier (Fig.…”

“…These properties can be further modified by changing pressure and/or temperature, and by addition of a modifier (Fig. 3), and show SC-CO 2 as convenient green and sustainable medium for designing enzymic processes [37].…”

Resolution of 2-bromo-arylacetic acid ester by Yarrowia lipolytica lipase in water/supercritical CO2 two-phase systems

“…Up to now, the effect of pressure on enzyme activity is not clearly understood [23]. Indeed, some authors reported that a large change of pressure, and in consequence of density, could significantly alter the interaction of CO 2 with the enzyme by formation of carbamates, from reaction of CO 2 with the free amine groups present on the surface of the enzyme [7,18,[24][25][26][27][28][29][30][31]. These carbamates could be responsible for charge removal of the histidine residues present at the active site of the enzyme, thus resulting in a decrease of its activity or even in its complete inactivation [29,32,33].…”

“…Also, increase of pressure induces changes in the supercritical phase properties. Some authors reported the variation with pressure of the dielectric constant [18,27,35,36], or of the logP [31,37] in the case of sc-fluoroform or scCO 2 (log P is related to hydrophilicity of the organic phase). However there is weak influence of pressure on the dielectric constant in the case of scCO 2 [38] but an important influence on the density, which could increase the interaction of this fluid with the lipase, and have an effect on enzyme activity.…”