Abstract
Supercritical fluids are a unique class of nonaqueous media in which biocatalytic reactions can occur. The physical properties of supercritical fluids, which include gas-like diffusivities and liquid-like densities, can be predictably controlled with changing pressure. This paper describes how adjustment of pressure, with the subsequent predictable changes of the dielectric constant and Hildebrand solubility parameter for fluoroform, ethane, sulfur hexafluoride, and propane, can be used to manipulate the activity of lipase in the transesterification of methylmethacrylate with 2-ethyl-1-hexanol. Of particular interest is that the dielectric constant of supercritical fluoroform can be tuned from approximately 1 to 8, merely by increasing pressure from 850 to 4000 psi (from 5.9 to 28 MPa). The possibility now exists to predictably alter both the selectivity and the activity of a biocatalyst merely by changing pressure.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Affleck R., Haynes C. A., Clark D. S. Solvent dielectric effects on protein dynamics. Proc Natl Acad Sci U S A. 1992 Jun 1;89(11):5167–5170. doi: 10.1073/pnas.89.11.5167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Affleck R., Xu Z. F., Suzawa V., Focht K., Clark D. S., Dordick J. S. Enzymatic catalysis and dynamics in low-water environments. Proc Natl Acad Sci U S A. 1992 Feb 1;89(3):1100–1104. doi: 10.1073/pnas.89.3.1100. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kamat S., Beckman E. J., Russell A. J. Role of diffusion in nonaqueous enzymology. 1. Theory. Enzyme Microb Technol. 1992 Apr;14(4):265–271. doi: 10.1016/0141-0229(92)90149-i. [DOI] [PubMed] [Google Scholar]
- Randolph T. W., Clark D. S., Blanch H. W., Prausnitz J. M. Cholesterol aggregation and interaction with cholesterol oxidase in supercritical carbon dioxide. Proc Natl Acad Sci U S A. 1988 May;85(9):2979–2983. doi: 10.1073/pnas.85.9.2979. [DOI] [PMC free article] [PubMed] [Google Scholar]