Increased activity of alcohol oxidase at high hydrostatic pressure

Abstract

Alcohol oxidase (AOx) from P. pastoris has potential applications in the production of carbonyl compounds and for the detection and quantification of alcohols. However, AOx’s poor stability and low activity have hindered its practical application. There are two fractions of AOx in P. pastoris with different thermal stability. High hydrostatic pressure (HHP) increased the activity of the labile (L) + resistant (R) combined fractions but not of the R fraction alone. The activity of the L + R fractions increased 2.4-fold at 160 MPa and 30 °C compared to the activity at 0.1 MPa. At higher temperatures, the increase in activity with pressure was greater due to the combined stabilization and activation effects. The reaction rate of the R fraction at 50 °C was 17.9 ± 3.6 or 17.7 ± 0.8 μM min−1 at 80 or 160 MPa, respectively, and was not significantly different from the activity of the L + R fractions under the same conditions (18.4 ± 2.7 μM min-1). The activation energy of the R fraction was not significantly different between 80 MPa (41.5 ± 10.5 kJ mol-1) and 160 MPa (43.8 ± 7.8 kJ mol-1). The combined increase in the stability of the R fraction at HHP enables the use of the enzyme at 50 °C with little loss of activity and an increased catalytic rate.