A liquid immobilisation concept for enzymes by thermomorphic solvent systems

17 Oct 2011

An new and innovative method of free enzyme recycling from a reaction mixture has been developed which relies only on the physical properties of the reaction medium.

Biotechnology is gaining an increasing role in industrial processes, but various factors including poor industrial availability of free enzymes and efficient recycling procedures limit utilization. Common methods for enzyme recycling include immobilization of the enzyme onto a suitable support material or by encapsulation in aqueous gels. However, disadvantages of these methods include leeching of enzymes and loss of activity.

Arno Behr and his team from the Technical University of Dortmund, Germany, have provided a new solution to the problem of enzyme recycling. They used a mixture of three solvents (water, methanol and hexanol) which are immiscible at room temperature. When heated to the reaction temperature, the solvents form one phase which allows the reaction to proceed with no mass-transfer limitations. Cooling the mixture to below the critical solution temperature leads to a biphasic system, resulting in the product phase being simply separated from the phase containing the catalyst, which can then be reused. The catalyst could be used again over 5 sequential runs with only a 2% loss in maximum yield.