Polyhydric alcohol protective effect on Rhizomucor miehei lipase deactivation enhanced by pressure and temperature treatment.

The influence of polyhydric alcohols (sorbitol, xylitol, erythritol, glycerol) on the thermal stability of Rhizomucor miehei lipase has been studied at high hydrostatic pressure (up to 500 MPa). In the absence of additives, a protective effect (PE) (the ratio between the residual activities determined at 480 MPa for the enzyme in the presence or absence of polyhydric alcohols) of low-applied pressures (from 50 MPa to 350 MPa) against thermal deactivations (at 50 degrees C and 55 degrees C) has been noticed. In the presence of additives, a strong correlation between PE and the total hydroxyl group concentration has been obtained, for the first time, under treatments of combining denaturing temperatures and high hydrostatic pressures.

Kinetic resolution of rac-2-pentanol catalyzed by Candida antarctica lipase B in the ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide.

The ionic liquid, l-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide ([Bmim] [NTf2]), was used as a reaction medium for the kinetic resolution of rac-2-pentanol catalyzed by free Candida antarctica lipase B, using vinyl propionate at 2% (v/v) water content. The synthetic activity of lipase in [Bmim] [NTf2] was up 2.5-times greater than in hexane, and showed high enantioselectivity (ee > 99.

Effects of temperature and pressure on Rhizomucor miehei lipase stability.

Both high temperature and high hydrostatic pressure induce irreversible deactivation of enzymes. They enable the enzyme's thermodynamic parameters to be determined and are used to study the mechanisms involved in biochemical systems. The effect of these two factors on the stability of Rhizomucor miehei lipase have been investigated.