Three Systems Used for Biocatalysis in Organic Solvents a Comparative Study

Abstract
The activity and operational stability of horse liver alcohol dehydrogenase (HLADH) and α-chymotrypsin were investigated in three systems commonly used for biocatalysis in organic solvents: 1. enzyme adsorbed on a solid support (celite) and added to the organic solvent (isooctane) 2. enzyme powder directly added to the organic solvent (isooctane). 3. enzyme dissolved in a microemulsion (AOT/isooctane). The activity and the operational stability in all systems were strongly dependent on the water content. The initial reaction rate was high in both the microemulsion and the celite system, but was much lower when adding the enzymes directly to the organic solvent. HLADH was observed to be more stable when added directly to the organic solvent or dissolved in the microemulsion than when adsorbed on celite, whereas for α-chymotrypsin stability was higher when adsorbed on celite or added directly to the organic solvent. For a hydrolytic reaction, a microemulsion was preferred due to the high water content. When adding the enzymes directly to the organic solvent both HLADH and chymotrypsin were adsorbed strongly to the glass walls of the reaction vessel. None of the systems were superior in all respects for the two enzymes studied.