Gas Hydrate Formation in Reversed Micelles

We describe a technique to modify protein solubility and optimize enzyme activity in reversed micellar solutions. The technique is based on the ability of hydrates of natural gas to form in the micro-aqueous phase. Clathrate hydrates are crystalline inclusions of water and gas, and their formation in bulk water has traditionally been studied with relevance to natural gas recovery. We have found that hydrates can form in the environment of the microaqueous pools of reversed micelles, and that their extent of formation can be well controlled through the thermodynamic variables of temperature and pressure. Additionally, formation of hydrates affects the size and aggregation number of the micelles, and thus influences the solubility and conformation of encapsulated proteins. We demonstrate how the concept can be used in two applications: (i) protein extraction into reversed micelles and subsequent recovery, and (ii) optimization of enzyme activity in reversed micelles.

[1]  P. Luisi.  Enzymes Hosted in Reverse Micelles in Hydrocarbon Solution , 1985 .

[2]  B. Halle,et al.  Water dynamics and aggregate structure in reversed micelles at sub-zero temperatures. A deuteron spin relaxation study , 1988 .

[3]  K. Martínek,et al.  Enzymes Entrapped Into Reversed Micelles Of Surfactants In Organic Solvents: Key Trends In Applied Enzymology (Biotechnology) , 1987 .

[4]  B. Jönsson,et al.  On the Activity of Water and the Concept of the Interfacial Free Energy in W/O‐Microemulsions , 1982 .

[5]  A. Pshezhetsky,et al.  Enzymes entrapped in reversed micelles of surfactants in organic solvents: A theoretical treatment of the catalytic activity regulation , 1988 .

[6]  P. Luisi,et al.  Reverse micelles as hosts for proteins and small molecules. , 1988, Biochimica et biophysica acta.

[7]  P. Luisi,et al.  Application of reverse micelles for the extraction of proteins. , 1986, Biochemical and biophysical research communications.

[8]  G. D. Holder,et al.  Multiple-phase equilibria in hydrates from methane, ethane, propane and water mixtures , 1982 .

[9]  M. Pileni,et al.  Solubilization by reverse micelles: Solute localization and structure perturbation , 1985 .

[10]  J. Fulton,et al.  Reverse micelle and microemulsion phases in supercritical fluids , 1988 .

[11]  T. A. Hatton,et al.  Liquid-Liquid Extraction of Low Molecular-Weight Proteins by Selective Solubilization in Reversed Micelles , 1987 .

[12]  J. Cabral,et al.  Recovery of an Extracellular Alkaline Protease From Whole Fermentation Broth Using Reversed Micelles , 1988 .