title: Optimization of a membraneless glucose/oxygen enzymatic fuel cell based on a bioanode with high coulombic efficiency and current density.
abstract: After initial testing and optimization of anode biocatalysts, a membraneless glucose/oxygen enzymatic biofuel cell possessing high coulombic efficiency and power output was fabricated and characterized. Two sugar oxidizing enzymes, namely, pyranose dehydrogenase from Agaricus meleagris (AmPDH) and flavodehydrogenase domains of various cellobiose dehydrogenases (DH(CDH)) were tested during the pre-screening. The enzymes were mixed, "wired" and entrapped in a low-potential Os-complex-modified redox-polymer hydrogel immobilized on graphite. This anode was used in combination with a cathode based on bilirubin oxidase from Myrothecium verrucaria adsorbed on graphite. Optimization showed that the current density for the mixed enzyme electrode could be further improved by using a genetically engineered variant of the non-glycosylated flavodehydrogenase domain of cellobiose dehydrogenase from Corynascus thermophilus expressed in E. coli (ngDH(CtCDHC310Y)) with a high glucose-turnover rate in combination with an Os-complex-modified redox polymer with a high concentration of Os complexes as well as a low-density graphite electrode. The optimized biofuel cell with the AmPDH/ngDH(CtCDHC310Y) anode showed not only a similar maximum voltage as with the biofuel cell based only on the ngDH(CtCDHC310Y) anode (0.55 V) but also a substantially improved maximum power output (20 μW cm(-2)) at 300 mV cell voltage in air-saturated physiological buffer. Most importantly, the estimated half-life of the mixed biofuel cell can reach up to 12 h, which is apparently longer than that of a biofuel cell in which the bioanode is based on only one single enzyme.
authors.affiliation: Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
authors.forename: Minling
authors.initials: M
authors.lastname: Shao
authors.forename: Muhammad Nadeem
authors.initials: MN
authors.lastname: Zafar
authors.forename: Magnus
authors.initials: M
authors.lastname: Falk
authors.forename: Roland
authors.initials: R
authors.lastname: Ludwig
authors.forename: Christoph
authors.initials: C
authors.lastname: Sygmund
authors.forename: Clemens K
authors.initials: CK
authors.lastname: Peterbauer
authors.forename: Dmitrii A
authors.initials: DA
authors.lastname: Guschin
authors.forename: Domhnall
authors.initials: D
authors.lastname: MacAodha
authors.forename: Peter
authors.initials: P
authors.lastname: Ó Conghaile
authors.forename: Dónal
authors.initials: D
authors.lastname: Leech
authors.forename: Miguel D
authors.initials: MD
authors.lastname: Toscano
authors.forename: Sergey
authors.initials: S
authors.lastname: Shleev
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
authors.forename: Lo
authors.initials: L
authors.lastname: Gorton
mesh_terms: D000364:Agaricus / Q000201:enzymology; D055162:Biocatalysis; D001674:Bioelectric Energy Sources; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D004566:Electrodes; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D020037:Sordariales / Q000201:enzymology
chemical_list: D002237:Carbohydrate Dehydrogenases; D007770:L-Lactate Dehydrogenase; D005947:Glucose; D010100:Oxygen
keywords: biofuel cells; cellobiose dehydrogenase; coulombic efficiency; electrochemistry; electron transfer