Stability and activity of lipase in subcritical 1,1,1,2-tetrafluoroethane (R134a)

Abstract

The stability and activity of commercial immobilized lipase from Candida antarctica (Novozym 435) in subcritical 1,1,1,2-tetrafluoroethane (R134a) was investigated. The esterification of oleic acid with glycerol was studied as a model reaction in subcritical R134a and in solvent-free conditions. The results indicated that subcritical R134a treatment led to significant increase of activity of Novozym 435, and a maximum residual activity of 300% was measured at 4 MPa, 30 degrees C after 7 h incubation. No deactivation of Novozym 435 treated with subcritical R134a under different operation factors (pressure 2-8 MPa, temperature 30-60 degrees C, incubation time 1-12 h, water content 1:1, 1:2, 1:5 enzyme/water, depressurization rate 4 MPa/1 min, 4 MPa/30 min, 4 MPa/90 min) was observed. While the initial reaction rate was high in subcritical R134a, higher conversion was obtained in solvent-free conditions. Though the apparent conversion of the reaction is lower in subcritical R134a, it is more practicable, especially at low enzyme concentrations desired at commercial scales.

Chemoenzymatic synthesis of polypeptides in neat 1,1,1,2-tetrafluoroethane solvent

“…However, water has low miscibility in this organic CF (1 g L −1 at 313.15 K), which precludes for water stripping. Additionally, the hydrogen-bonding capacity associated with fluorine atoms might be relevant in keeping the configuration at the enzyme active site at the operational temperatures, as reported by Yu et al 24 Therefore, the evidence might suggest that the polarity and hydrophobicity of this organic CF, as well as the hydrogen-bonding capacity of the fluorine moieties, might explain the SC activity in this system.…”

“…22,23 This low-boiling hydrouorocarbon becomes easily liquid under small pressure and solubilizes relatively polar substrates while keeping its hydrophobic and aprotic characteristics to inhibit depolymerization and more importantly, to sustain hydrolasetype activities for biotransformations. [24][25][26] This work is rst to describe a chemoenzymatic synthesis of polypeptides in this neat uid (313.15 K, 25 bar). For this purpose, L-leucine and Lphenylalanine ethyl esters were used as model substrates and the consequent products were attained in higher yields and molar masses than previous protease-mediated approaches.…”

Green Extraction of Artemisinin from Artemisia annua L

“…More recently, R134a solvent has received considerably more attention as a viable extraction solvent for food products [45][46][47]. [48,49]. [48,49].…”

Enzymatic syntheses of linear and hyperbranched poly-l-lactide using compressed R134a–ionic liquid media

“…Recently, compressed R134a (1,1,1,2-tetrafluoroethane), a green and non-toxic organic CF, which can be compressed to an hydrophobic and relatively polar liquid o supercritical fluid allowing lipase activities [12,13], was employed for eROP of LLA using non-supported lipase from Burkholderia cepacia (lipase BC) [14]. The compressed R134a present the advantage over compressed CO 2 of being relatively polar with similar physicochemical characteristics to that of the inorganic CF even at relatively low operating pressures [15,16].…”