Surface Display of Redox Enzymes in Microbial Fuel Cells

Abstract

A novel concept for a biofuel cell is presented. Enzyme based fuel cells suffer from enzyme instability when a long time of operation is required. Hence, a system that will continuously produce the biocatalyst needed for the system is necessary. A hybrid of an enzyme-based microbial fuel cell was developed. The redox enzyme glucose oxidase from Aspergillus niger was displayed on the surface of Saccharomyces cerevisiae using the Yeast Surface Display System in a high copy number and as an active enzyme. We have demonstrated its activity both biochemically and electrochemically and observed much higher activity over yeast cells not displaying glucose oxidase as well as over purified glucose oxidase from Aspergillus niger. Further, we were able to construct a biofuel cell, where the anode was comprised of the yeast cells displaying glucose oxidase in the presence of a mediator (methylene blue) and the cathode compartment was comprised of the oxygen reducing enzyme laccase from Trametes versicolor and a redox mediator. Our constructed biofuel cell displayed higher power outputs and current densities than those observed for unmodified yeast and a much longer time of operation in comparison with a similar cell where the anode is comprised of purified glucose oxidase.

Genetically Engineered Microbial Fuel Cells

“…As surface display systems evolved and became more robust, the number and variety of their uses have grown tremendously to include such exciting applications as proteins displays for biosensing [53,54]. Recently we were able to display on the surface of bakers yeast (Saccharomyces cerevisiae) the enzyme glucose oxidase (GOx) and we used it in an MFC [55]. Primary metabolite is used directly by the displayed enzyme and the corresponding electron is delivered directly or indirectly by the enzyme to the electrode.…”

“…Our team has displayed the enzyme glucose oxidase (GOx) on the surface of bakers yeast Saccharomyces cerevisiae (S. cerevisiae) using the a-agglutinin display system [55]. We have used the modified yeast at the anode compartment of a biofuel cell.…”

An“ON–OFF” switchable power output of enzymatic biofuel cell controlled by thermal-sensitive polymer

“…EBFCs suffer from a very prominent disadvantage for long-term operation, due to loss in enzyme activity. (Fishilevich et al, 2009;Liu et al, 2010) The E cell ocv of the EBFC at "ON" state (20°C) was continuously recorded over 40 days. Both glucose and O 2 were renewed every two days during the 40 days in order to exclude the effect of the substrate.…”

A quinhydrone biofuel cell based on an enzyme-induced pH gradient

“…[3]. A vast majority of these biofuel cells produce electrical energy from glucose and oxygen via enzymes electrically wired by redox mediators [4][5][6][7][8][9][10][11]. Conventional biofuel cells are based on enzymes and redox mediators immobilized on the electrodes, glucose being oxidised into gluconolactone and oxygen being reduced into water.…”