Advertisement

Biotransformations in Supercritical Fluids

  • Nuno Fontes
  • M. Conceição Almeida
  • Susana Barreiros
Part of the Methods in Biotechnology book series (MIBT, volume 15)

Abstract

A substance is said to be supercritical (SC) above a singular point on the phase diagram, the so-called critical point. The use of SC fluids as solvents for enzymatic transformations is a relatively new area of research (1,2) that is expected to expand in the future. Close to the critical point, small changes in temperature or pressure can effect large changes in the density/solvation ability of SC-fluid. This property of SC-fluids is currently used in a wide range of extraction applications. It can also be fruitfully exploited for the integration of biotransformation and downstream processing steps in a single bioreactor. In addition, lower viscosity and higher diffusivity of SC-fluids as compared to most organic solvents enable better mass transfer, which is often a limiting factor in reaction systems where the enzyme and reactants are not contained in the same phase.

Keywords

Open Valve Close Valve Karl Fischer Titration Sapphire Window Good Mass Transfer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Randolph, T. W., Blanch, H. W., Prausnitz, J. M., and Wilke, C. R. (1985) Enzymatic catalysis in a supercritical fluid. Biotechnol. Lett. 7, 325–328.CrossRefGoogle Scholar
  2. 2.
    Hammond, D. A., Karel, M., Klibanov, A. M., and Krukonis, V. J. (1985) Enzymatic reactions in supercritical gases. Appl. Biochem. Biotechnol. 11, 393–400.CrossRefGoogle Scholar
  3. 3.
    Partridge, J., Dennison, P. R., Moore, B. D., and Halling, P. J. (1998) Activity and mobility of subtilisin in low water organic media: hydration is more important than solvent dielectric. Biochim. Biophys. Acta 1386, 79–89.CrossRefGoogle Scholar
  4. 4.
    Xu, Z.-F., Affleck, R., Wangikar, P., Suzawa, V., Dordick, J. S., and Clark, D. S. (1994) Transition state stabilization of subtilisins in organic media. Biotechnol. Bioeng.43, 515–520.CrossRefGoogle Scholar
  5. 5.
    Bell, G., Halling, P. J., Moore, B. D., Partridge, J., and Rees, D. G. (1995) Biocatalyst behaviour in low-water systems. Trends Biotechnol. 13, 468–473.CrossRefGoogle Scholar
  6. 6.
    Zacharis, E., Omar, I. C., Partridge, J., Robb, D. A., and Halling, P. J. (1997) Selection of salt hydrate pairs for use in water control in enzyme catalysis in organic solvents. Biotechnol. Bioeng. 55, 367–374.CrossRefGoogle Scholar
  7. 7.
    Almeida, M. C., Ruivo, R., Maia, C., Freire, L., Corrêa de Sampaio, T., and Barreiros, S. (1998) Novozym 435 activity in compressed gases. water activity and temperature effects. Enzyme Microb. Technol. 22, 494–499.CrossRefGoogle Scholar
  8. 8.
    Fontes, N., Almeida, M. C., Peres, C., Garcia, S., Grave, J., Aires-Barros, M. R., et al. (1998) Cutinase activity and enantioselectivity in supercritical fluids. Ind. Eng. Chem. Res. 37, 3189–3194.CrossRefGoogle Scholar
  9. 9.
    Corrêa de Sampaio, T. and Barreiros, S. (2000) Transesterification reactions catalyzed by subtilisin Carlsberg suspended in supercritical carbon dioxide and in supercritical ethane, in Methods in Biotechnology, vol. 13: Supercritical Fluid Methods and Protocols (Williams, J. R. and Clifford, A. A., eds.), Humana, Totowa, NJ, pp. 179–188.CrossRefGoogle Scholar

Copyright information

© Humana Press Inc. 2001

Authors and Affiliations

  • Nuno Fontes
    • 1
  • M. Conceição Almeida
    • 1
  • Susana Barreiros
    • 1
  1. 1.Universidade Nova de LisboaInstituto de Tecnologia Quimica e BiologicaOeirasPortugal

Personalised recommendations