Enzymatic Reactions in Near Critical CO2: The Effect of Pressure on Phenol Removal by Tyrosinase

Abstract

The use of enzymes in supercritical CO2 (SCCO2) has received extensive attention in recent years. Biocatalysts have the advantage of substrate specificity and SCCO2 offers several advantages over liquid solvents. This work deals with the utilization of SCCO2 as a medium for the enzymatic removal of phenol from aqueous solutions using tyrosinase. Since the presence of oxygen is crucial for the enzyme-catalyzed oxidation, the substantial solvating power of SCCO2 makes it a promising medium for such reactions. The conversion of phenol was higher at 10 MPa. Under near critical conditions (7 MPa, 35 °C), the addition of air at 5 × 105 Pa of pressure improved phenol removal.

Complete Reduction of Polychlorinated Biphenyls by Acid-Etched Steel Wool in Supercritical Carbon Dioxide

“…The use of scCO 2 does not have the drawback of leaving solvent residues in the reaction products because CO 2 is gaseous under atmospheric conditions. 19,20 CO 2 is considered one of the greenest solvents available at present due to its recyclability 21 and its potential as storage for the reduction of this greenhouse gas in the atmosphere. 22,23 Steel wool is generally used for cleaning, smoothing, grinding, antiquing, or filtration.…”

“…Moreover, product recovery is facile by simple depressurization of the reaction mixture. The use of scCO 2 does not have the drawback of leaving solvent residues in the reaction products because CO 2 is gaseous under atmospheric conditions. , CO 2 is considered one of the greenest solvents available at present due to its recyclability and its potential as storage for the reduction of this greenhouse gas in the atmosphere. , …”