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Use of PIT (phase inversion by temperature) nano-emulsions in biocatalytic reactions


Key words Phase inversion temperature process, emulsion, droplet size, biocatalysis, reaction medium, aqueous system
Latest version 2012/10/10
Completed by INRA - IATE

How does it work?

Primary objective Improvement of catalytic reactions in aqueous medium, even with poorly water-soluble substances, with no solvents and under mild mixing conditions. This is particularly suitable for water-insoluble substrates or with enzymes that show too little stability or activity in conventional organic solvent systems.
Working principle Oil-in-water (o/w) emulsions prepared and stabilized with non-ionic emulsifiers can change from o/w to w/o emulsion within a certain temperature range (heating), defined as PIT (phase inversion temperature) and depending on a number of factors.

PIT emulsions that form a microemulsion phase with low interfacial tension between oil and water or a lamellar liquid-crystalline phase during phase inversion are characterized by particularly small droplets. As these fine-droplet emulsions retain their homogeneity through Brownian molecular movement, need for energy- intensive stirring may be reduced.

The very high specific surface, the stability and the repeatability of the quality of the obtained emulsion are major advantages over conventional emulsions for enzyme-catalyzed reactions in multiphase systems.

Additional effects The product in the oil phase can be readily separated from the aqueous phase by mild heating (inversion temperature can be adjusted through the control of emulsifier system) or used as the dispersible nano-emulsion.
Important process parameters temperature control, choice of the nature and amounts of water, oil, emulsifier(s), catalyst(s)
Important product parameters -

What can it be used for?

Products Products obtained by food-grade enzyme-catalyzed reactions, e.g. vegetable oil-based derivatives with antioxidant, nutritional or technological interest, in pure form or as the dispersible emulsion product.
Operations biocatalysis
Solutions for short comings Need for an alternative to organic solvent- based biocatalytic processes and to conventional emulsion reaction media (problems of low repeatability, stability and specific surface area).

What can it NOT be used for?

Products The biocatalyst and the emulsifier system must be food-grade for products directly used in food.

Reactions producing emulsifiers may have a negative impact on the PIT emulsion stability and pose separation problems.

Operations The applications are limited to systems where at least one reactant is non-water soluble.
Other limitations not known
Risks or hazards not known


Maturity PIT emulsion technology is available at industrial scale, but applications in biocatalysis are currently at lab scale.
Modularity /Implementation This bioprocess technology can replace a bioprocess with a conventional device.
Consumer aspects Not known; consumers should be benevolent regarding an environmentally-friendly process.
Legal aspects an international patent has been registered (2)
Environmental aspects This technology allows running reactions in aqueous systems with non-ionic emulsifiers and without organic solvents, in mild temperature and pH conditions, and with lower energy consumption than conventional systems.

Further Information

Institutes INRA - IATE
Companies Cognis
References Patents:

1. Dubreucq E., Weiss A. and Molitor J.P., 2006. Use of PIT emulsions in lyase- or oxidoreductase-catalysed methods for the production of cyanohydrins. Patent EP2006001041, WO06087119.

2. Weiss A., Dubreucq E. and Molitor J.P., 2006. Use of PIT emulsions in biocatalytic reactions. Patent WO 2006087119.

3. Weiss A., Müller M., Dubreucq E., Moulin G., 2010. Emulsions in Enzymatic Reactions. Patent US20100323415

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Created by Hte inra on 23 September 2011, at 10:40