TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Component: The catalytically active material includes an enzyme that is bound directly or indirectly to a polyelectrolyte. The enzyme is oxidoreductase, dehydrogenase, secondary alcohol dehydrogenase or mannitol dehydrogenase. The active material may include xylose isomerase and mannitol dehydrogenase.    TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Component: The carbon electrode is a glassy carbon electrode or reticulated vitreous carbon electrode.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The exfoliated graphite nanoplatelets are incorporated as a component of the bioelectronic interface.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: A polyelectrolyte is electrostatically bound directly to the surface of the carbon electrode. The polyelectrolyte is electrostatically bound to an ionic linker that is covalently bound to the surface of the electrically conductive carbon electrode. The ionic linker that is covalently bound to a carbon atom at the surface of the electrically conductive carbon electrode is glycine. The polyelectrolyte that is covalently bound to a carbon atom at the surface of the electrically conductive carbon electrode comprises a compound that includes a linking moiety covalently bound to the carbon atom at the surface of the electrically conductive carbon electrode, and further includes at least one ionized moiety for achieving the direct or indirect electrostatic bonding of the catalytically active material to the electrically conductive carbon electrode. The bioelectronic interface further comprises a redox cofactor that facilitates or enhances activity of the catalytically active material. It includes an electron mediator that reduces the electrical potential needed to transfer electrons during a chemical reaction. The electron mediator is toluidine blue O, neutral red or Nile blue A. The redox cofactor comprises nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide, or flavin mononucleotide. A boronate linkage is used to bind the redox cofactor to the polyelectrolyte that is electrostatically bound directly or indirectly to the surface of the carbon electrode. Fullerenes are incorporated as a component of the bioelectronic interface. The cathode is an electrically conductive carbon electrode having a bioelectronic interface comprising xylose isomerase and mannitol dehydrogenase bound to the surface of the cathode, where the anode is an electrically conductive carbon electrode having a bioelectronic interface comprising glycerol dehydrogenase, where the reactor is configured to produce mannitol from glucose and simultaneously produce dihydroxyacetone from glycerol.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: A polyelectrolyte is electrostatically bound directly to the surface of the carbon electrode. A redox cofactor and an electron mediator is associated with multiple layers that are bound together by alternating layers of oppositely charged polyelectrolytes. The polyelectrolytes are polyethyleneimine and polyacrylic acid. A branched heterotri-functional linking molecule and polyelectrolytes are used to couple the enzymes, and optionally couple a redox cofactor for the enzymes, and optionally couple an electron mediator for the redox cofactors.