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ARS Home » Research » Publications at this Location » Publication #124849
Title: SIZE AS A PARAMETER FOR SOLVENT EFFECTS ON CANDIDA ANTARCTICA LIPASE B ENANTIOSELECTIVITY

Author
item OTTOSSON, JENNY - ROYAL INST OF TECHNOLOGY
item FRANSSON, LINDA - ROYAL INST OF TECHNOLOGY
item King, Jerry
item HULT, KARL - ROYAL INST OF TECHNOLOGY

Submitted to: Biochimica et Biophysica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Natural enzymes can be used in a variety of solvents to make active flavor agents, cosmetic ingredients or medicines out of ones with little or no effective ingredient. Different solvents cause the enzyme to make different amounts and kinds of the useful products. In this study, we found that an environmentally friendly, non-toxic solvent, compressed carbon dioxide caused an enzyme to produce lower, but acceptable, amounts of one kind of the chemicals needed in products than the kind not needed in products. This helps us to better understand how to use compressed carbon dioxide in place of toxic solvents to make consumer and industrial products using natural enzymes.

Technical Abstract: Simple solvent changes were shown to yield significant improvement of enzyme enantioselectivity. The resolution of 3- methyl-2- butanol catalyzed by Candida antarctica lipase B, CALB, was studied in eight liquid organic solvents and supercritical carbon dioxide, SCCO2. Studies of the temperature dependence of the enantiomeric ratio allowed determination of the enthalpic (DeltaR-SDeltaH++) as well as the entropic (DeltaR-SDeltaS++) contribution to the overall enantioselectivity (DeltaR-SDeltaG++ = -RtlnE). A correlation of the enantiomeric ratio, E, to the van der Waals volume of the solvent molecules was observed and suggested as one of the parameters that govern solvent effects on enzyme catalysis. Enthalpy-entropy compensation was indicated within the liquid solvents. The enzyme mechanism must be of a somewhat different nature in SCCO2, as this reaction did not follow the enthalpy-entropy compensation relation.