Improved Bioelectrocatalytic Oxidation of Sucrose in a Biofuel Cell with an Enzyme Cascade Assembled on a DNA Scaffold

The employment of multi-enzyme cascades as catalysts is a promising strategy to improve performance of enzymatic biofuel cells, as it allows for the conversion of more chemical energy stored in complex fuels. However, the performance of these enzyme systems is often limited by the mass transport of intermediate substrates between enzymes. Nature addresses this issue by organizing metabolic enzymes in a sequential and proximal manner to enhance the efficiency of metabolic pathways. In this work, we investigate the utilization of DNA as a structural scaffold for assembly of the invertase/glucose oxidase enzyme cascade to improve sucrose bioelectrocatalytic activity. It has been found that the DNA-assembled enzyme cascade has higher activity than the free cascade, both in solution and in the immobilized state on an electrode surface. The organization of the enzyme cascade on the DNA scaffold leads to a 100% increase in the current density in amperometric measurements and a 75% increase in the power density of the biofuel cell. This is the first evidence of the advantages of utilizing DNA scaffords for improved bioelectrocatalysis.