Methods and apparatus for performing electrochemical and enzymatic reactions

Abstract

Methods and apparatus for performing coupled electrochemical and enzymatic reactions are disclosed. The method comprises applying an electrical potential between an anode and a metallic membrane. A hydrogen-containing compound may be electrochemically dissociated at the anode to form hydrogen ions. The hydrogen ions may be transported to a first surface of the metallic membrane and thereon, the hydrogen ions are reduced to form hydrogen atoms. The hydrogen atoms may then diffuse through the metallic membrane to reach an opposing second surface of the metallic membrane in an enzyme compartment. At the second surface, electrons are transferred to the hydrogen atom to form hydride ions. The hydride ions may react with oxidized cofactors in the enzyme compartment to form reduced cofactors. In some embodiments, the reduced cofactors is used by an enzyme in an enzymatic reaction with a substrate to form one or more products and releases an oxidized cofactor.

What is claimed is: 
     
         1 . A method for performing coupled electrochemical and enzymatic reactions, the method comprising:
 applying an electrical potential between an anode and a metallic membrane;   electrochemically dissociating, at the anode, a hydrogen-containing compound to form hydrogen ions;   transporting the hydrogen ions to a first surface of the metallic membrane;   at the first surface of the metallic membrane, reducing the hydrogen ions to form hydrogen atoms;   diffusing the hydrogen atoms through the metallic membrane to an opposing second surface of the metallic membrane in an enzyme compartment;   at the second surface of the metallic membrane, transferring electrons to the hydrogen atoms to form hydride ions; and   reacting the hydride ions with oxidized cofactors in the enzyme compartment to form reduced cofactors.   
     
     
         2 . The method as defined in  claim 1 , further comprising flowing a supply of enzymes and substrates to the enzyme compartment. 
     
     
         3 . The method as defined in  claim 2 , further comprising reacting the substrate with the enzyme and the reduced cofactors in the enzyme compartment to yield one or more products and to release oxidized cofactors. 
     
     
         4 . The method as defined in  claim 1 , wherein transferring an electron from the metallic membrane to the hydrogen atoms to form hydride ions at the second surface releases the hydride ions into the enzyme compartment. 
     
     
         5 . The method as defined in  claim 1 , wherein transferring the electron from the metallic membrane to the hydrogen atoms to form hydride ions at the second surface is performed in a solvent. 
     
     
         6 . The method as defined in  claim 5 , wherein the solvent comprises a proton source. 
     
     
         7 . The method as defined in  claim 5 , wherein the solvent comprises water. 
     
     
         8 . The method as defined in  claim 5 , wherein the solvent comprises a buffer solution. 
     
     
         9 . The method as defined in  claim 5 , wherein the method comprises maintaining a pH of the solvent in the range of from about 6 to about 10. 
     
     
         10 . The method as defined in  claim 1 , wherein reacting the hydride ions with oxidized cofactors in the enzyme compartment to form reduced cofactors is performed at the second surface of the metallic membrane. 
     
     
         11 . The method as defined in  claim 3 , wherein reacting the substrates with the enzymes and the reduced cofactors releases the oxidized cofactors into the enzyme compartment, and wherein the method further comprises transporting the released oxidized cofactors to the second surface of the metallic membrane for reaction with the hydride ions. 
     
     
         12 . The method as defined in  claim 1 , wherein the metallic membrane comprises a dense metallic hydrogen selective layer. 
     
     
         13 . The method as defined in  claim 12 , wherein the hydrogen selective layer comprises a layer of palladium or palladium alloy. 
     
     
         14 . The method as defined in  claim 1 , wherein reacting the hydride ions with oxidized cofactors in the enzyme compartment to form reduced cofactors is catalyzed by one or more layers of co-catalysts on the metallic membrane. 
     
     
         15 . The method as defined in  claim 14 , wherein the one or more layers of co-catalyst comprises one or more transition metals. 
     
     
         16 . The method as defined in  claim 15 , wherein the one or more transition metals comprises one or both of palladium and platinum. 
     
     
         17 . The method as defined in  claim 1 , wherein the electrochemically dissociating, at the anode, a hydrogen-containing compound additionally forms oxygen gas. 
     
     
         18 . The method as defined in  claim 1 , further comprising supplying a flow of inert gas into the enzyme compartment to create an inert gas atmosphere. 
     
     
         19 . The method as defined in  claim 1 , wherein the method comprises maintaining a physiological temperature in the enzyme compartment of greater than about 30° C. 
     
     
         20 . A method of performing coupled electrochemical and enzymatic reactions, the method comprising:
 applying an electrical potential between an anode and a metallic membrane;   electrochemically dissociating, at the anode, a hydrogen-containing compound to form hydrogen ions;   transporting the hydrogen ions to a first surface of the metallic membrane;   at the first surface of the metallic membrane, reducing the hydrogen ions to form hydrogen atoms;   diffusing the hydrogen atoms through the metallic membrane to an opposing second surface of the metallic membrane in an enzyme compartment;   at the second surface of the metallic membrane, transferring electrons to the hydrogen atoms to form hydride ions in a solvent comprising a proton source;   reacting the hydride ions with oxidized cofactors in the enzyme compartment to form reduced cofactors;   reacting an enzyme and the reduced cofactors with a substrate to yield one or more products and oxidized cofactors, thereby releasing the oxidized cofactors into the enzyme compartment; and   transporting the released oxidized cofactors within the enzyme compartment toward the second surface of the metallic membrane for reaction with the hydride ions to form the reduced cofactors for reactions with the enzyme and the substrate.