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At least 19 recordsLinked to original sources
PubMed2002

A glucose/hydrogen peroxide biofuel cell that uses oxidase and peroxidase as catalysts by composite bulk-modified bioelectrodes based on a solid binding matrix.

An improved composite bulk-modified bioelectrode setup based on a solid binding matrix (SBM) has been used to develop a glucose/hydrogen peroxide biofuel cell. Fuel is combined through a catalytically promoted reaction with oxygen into and oxidized species and electricity. The present work explores the feasibility of a sugar-feed biofuel cell based on SBM technology. The biofuel cell that utilizes mediators as electron transporters from the glucose oxidation pathway of the enzyme directly to electrodes is considered in this work. The anode was a glucose oxidase (GOx, EC 1.1.3.4)/ferrocene-modified SBM/graphite composite electrode. The cathode was a horseradish peroxidase (HRP, EC 1.11.1.7)/ferrocene-modified SBM/graphite composite electrode. The composite transducer material was layered on a wide polymeric surface to obtain the biomodified electrodic elements, anodes and cathodes and were assembled into a biofuel cell using glucose and H(2)O(2) as the fuel substrate and the oxidizer. The electrochemical properties and the characteristics of single composite bioelectrodes are described. The open-circuit voltage of the cell was 0.22 V, and the power output of the cell was 0.15 microW/cm(2) at 0.021 V. The biofuel cell proved to be stable for an extended period of continuous work (30 days). The reproducibility of the biotransducers fabrication was also investigated. In addition, an application of presented biofuel cell, e.g. the use of hydrolyzed corn syrup as renewable biofuels, was discussed.

Electrodes↗
PubMed2003

A biofuel cell with electrochemically switchable and tunable power output.

An electroswitchable and tunable biofuel cell based on the biocatalyzed oxidation of glucose is described. The anode consists of a Cu(2+)-poly(acrylic acid) film on which the redox-relay pyrroloquinoline quinone (PQQ) and the flavin adenine dinucleotide (FAD) cofactor are covalently linked. Apo-glucose oxidase is reconstituted on the FAD sites to yield the glucose oxidase (GOx)-functionalized electrode. The cathode consists of a Cu(2+)-poly(acrylic acid) film that provides the functional interface for the covalent linkage of cytochrome c (Cyt c) that is further linked to cytochrome oxidase (COx). Electrochemical reduction of the Cu(2+)-poly(acrylic acid) films (applied potential -0.5 V vs SCE) associated with the anode and cathode yields the conductive Cu(0)-poly(acrylic acid) matrixes that electrically contact the GOx-electrode and the COx/Cyt c-electrode, respectively. The short-circuit current and open-circuit voltage of the biofuel cell correspond to 105 microA (current density ca. 550 microA cm(-2)) and 120 mV, respectively, and the maximum extracted power from the cell is 4.3 microW at an external loading resistance of 1 kOmega. The electrochemical oxidation of the polymer films associated with the electrodes (applied potential 0.5 V) yields the nonconductive Cu(2+)-poly(acrylic acid) films that completely block the biofuel cell operation. By the cyclic electrochemical reduction and oxidation of the polymer films associated with the anode and cathode between the Cu(0)-poly(acrylic acid) and Cu(2+)-poly(acrylic acid) states, the biofuel cell performance is reversibly switched between "ON" and "OFF" states, respectively. The electrochemical reduction of the Cu(2+)-polymer film to the Cu(0)-polymer film is a slow process (ca. 1000 s) because the formation and aggregation of the Cu(0)-clusters requires the migration of Cu(2+) ions in the polymer film and their reduction at conductive sites. The slow reduction of the Cu(2+)-polymer films allows for the controlling of the content of conductive domains in the films and the tuning of the output power of the biofuel cell. The electron-transfer resistances of the cathodic and anodic processes were characterized by impedance spectroscopy. Also, the overall resistances of the biofuel cell generated by the time-dependent electrochemical reduction process were followed by impedance spectroscopy and correlated with the internal resistances of the cell upon its operation.

Bioelectric Energy Sources↗
PubMed2001

Emission factors of carbon monoxide and size-resolved aerosols from biofuel combustion.

This study reports emission factors of carbon monoxide and size-resolved aerosols from combustion of wood, dung cake, and biofuel briquette in traditional and improved stoves in India. Wood was the cleanest burning fuel, with higher emissions of CO from dung cake and particulate matter from both dung cake and briquette fuels. Combustion of dung cake, especially in an improved metal stove, resulted in extremely high pollutant emissions. Instead, biogas from anaerobic dung digestion should be promoted as a cooking fuel for public health protection. Pollutant emissions increased with increasing stove thermal efficiency, implying that thermal efficiency enhancement in the improved stoves was mainly from design features leading to increased heat transfer but not combustion efficiency. Compared to the traditional stove, the improved stoves resulted in the lower pollutant emissions on a kW h-1 basis from wood combustion but in similar emissions from briquette and dung cake. Stove designs are needed with good emissions performance across multiple fuels. Unimodal aerosol size distributions were measured from biofuel combustion with mass median aerodynamic diameters of 0.5-0.8 micron, about a factor of 10 larger than those from fossil fuel combustion (e.g. diesel), with potential implications for lung deposition and health risk.

Aerosols↗
PubMed2003

Characteristics of a miniature compartment-less glucose-O2 biofuel cell and its operation in a living plant.

We report the temperature, pH, glucose concentration, NaCl concentration, and operating atmosphere dependence of the power output of a compartment-less miniature glucose-O(2) biofuel cell, comprised only of two bioelectrocatalyst-coated carbon fibers, each of 7 micro m diameter and 2 cm length (Mano, N.; Mao, F.; Heller, A. J. Am. Chem. Soc. 2002, 124, 12962). The bioelectrocatalyst of the anode consists of glucose oxidase from Aspergillus niger electrically "wired" by polymer I, having a redox potential of -0.19 V vs Ag/AgCl. That of the cathode consists of bilirubin oxidase from Trachyderma tsunodae "wired" by polymer II having a redox potential of +0.36 V vs Ag/AgCl (Mano, N.; Kim, H.-H.; Zhang, Y.; Heller, A. J. Am. Chem. Soc. 2002, 124, 6480. Mano, N.; Kim, H.-H.; Heller, A. J. Phys. Chem. B 2002, 106, 8842). Implantation of the fibers in the grape leads to an operating biofuel cell producing 2.4 micro W at 0.52 V.

Bioelectric Energy Sources↗
PubMedDate not supplied

Investigation on organic pollutants from a domestic heating system using various solid biofuels.

Various herbaceous biofuels (straw, whole plant cereals and set aside hay) and spruce wood were tested for their potential to form PCDD/F, PCPh, PCBz and PAH during combustion. The trials were conducted in an automatically charged multi-fuel furnace for domestic applications (50 kWth). Both, flue gas and the different ash fractions were analysed. CO-emission results show, that combustion conditions were relatively uniform (mean CO-level: 200 mg/m3 at 13% O2 in flue gas). Likewise, the TOC- and PAH-emissions in the fuel gas remained constantly on a relatively low level. However, for the PCDD/F, PCPh and PCBz increased emissions were detected when herbacious fuels were applied. This may be attributed to their higher chlorine concentration and the high ash content, which is responsible for increased dust emissions during combustion. Similar observations were also found for the PCDD/F-concentrations in the ashes. Combustion chamber ashes usually showed a drastically reduced contamination with highly toxical compounds, compared to the ash fraction from the heat exchanger ash or to chimney soot.

Air Pollutants↗
PubMed2002

The yield and composition of switchgrass and coastal panic grass grown as a biofuel in southern England.

Switchgrass (Panicum virgatum L.) and coastal panic grass (Panicum amarum A.S. Hitchc. & Chase) are perennial grasses indigenous to North America. Switchgrass has been shown to have good potential as a biofuel crop in both the US and Canada. In the study reported here, seven varieties of switchgrass and one panic grass were evaluated for 5 years under the temperate maritime conditions in Southern England. Both species had 0 or 60 kg N ha(-1) applied annually in spring as treatment. Yield was measured after flowering and when stems were dead in the winter. Yield increased annually for 4-5 years except for the variety Dacotah, and in the fifth year dead stem yields ranged from 8.82 to 13.97 t dm ha(-1). There was no response to N except for one variety in one year. Mineral concentration in biomass was higher at flowering than at dead stem harvest and delaying harvesting further provided more time for P, K and Cl to be leached but yield also declined.

Agriculture↗
PubMed2002

Immobilisation of enzymes on poly(aniline)-poly(anion) composite films. Preparation of bioanodes for biofuel cell applications.

Immobilisation of enzymes is important for applications such as biosensors or biofuel cells. A poly(histidine) tag had been introduced on the C terminus of a lactate dehydrogenase enzyme. This mutant enzyme was then immobilised onto poly(aniline) (PANi)-poly(anion) composite films, PANi-poly(vinylsulfonate) (PVS) or PANi-poly(acrylate) (PAA). The NADH produced by the immobilised enzyme in the presence of beta-nicotinamide adenine dinucleotide (NAD(+)) and lactate is oxidised at the poly(aniline)-coated electrode at 0.05 to 0.1 V vs. saturated calomel electrode (SCE) at 35 degrees C.

Aniline Compounds↗
PubMed2003

Bioelectrocatalysis-based application of quinoproteins and quinoprotein-containing bacterial cells in biosensors and biofuel cells.

Electrochemical studies on the applied aspects of quinoproteins are briefly reviewed. Catalytic reactions of quinoprotein enzymes can be connected to electrochemical reactions directly or by the mediation of molecules functioning as electron acceptors of the enzymes. Such an enzyme-electrochemical reaction is called bioelectrocatalysis. It provides a novel method of kinetic analysis of enzyme catalysis and even whole bacterial cell catalysis. The principle of bioelectrocatalysis is first described, then, the bioelectrocatalysis-based application of quinoproteins in biosensors is mentioned. Characteristics and performance of this type of biosensor is explained by citing our own work. Possible application in bioreactors and biofuel cells is also mentioned.

Bacteria↗
PubMed2002

A miniature biofuel cell operating in a physiological buffer.

A glucose-O2 biofuel cell, consisting only of two electrocatalyst coated 7-mum diameter, 2-cm long carbon fibers is reported. The cell operated continuously at 0.52 V at 37 degrees C in a physiological buffer solution for a week, producing 1.9 muW during the first and 1.0 muW during the last day, generating in the period 0.9 J of electrical energy while passing a charge of 1.7 C. If a similar dimension zinc fiber were utilized in a battery at 100% current efficiency, only 0.016 C would have been generated.

Bioelectric Energy Sources↗
PubMed1998

Indoor biofuel air pollution and respiratory health: the role of confounding factors among women in highland Guatemala.

BACKGROUND: A number of studies have reported associations between indoor biofuel air pollution in developing countries and chronic obstructive lung disease (COLD) in adults and acute lower respiratory infection (ALRI) in children. Most of these studies have used indirect measures of exposure and generally dealt inadequately with confounding. More reliable, quantified information about this presumed effect is an important pre-requisite for prevention, not least because of the technical, economic and cultural barriers to achieving substantial exposure reductions in the world's poorest households, where ambient pollution levels are typically between ten and a hundred times higher than recommended standards. This study was carried out as part of a programme of research designed to inform the development of intervention studies capable of providing quantified estimates of health benefits. METHODS: The association between respiratory symptoms and the use of open fires and chimney woodstoves ('planchas'), and the distribution of confounding factors, were examined in a cross-sectional study of 340 women aged 15-45 years, living in a poor rural area in the western highlands of Guatemala. RESULTS: The prevalence of reported cough and phlegm was significantly higher for three of six symptom measures among women using open fires. Although this finding is consistent with a number of other studies, none has systematically examined the extent to which strong associations with confounding variables in these settings limit the ability of observational studies to define the effect of indoor air pollution adequately. Very strong associations (P < 0.0001) were found between the type of fire and a number of household and socioeconomic factors including the arrangement of rooms, floor type, and possession of a radio and television. The spouse's economic activity type was also significantly associated (P < 0.05). Thus, while 82% of open fire users had dirt floors and only 18% cement or tile floors, the situation was reversed for plancha users, only 16% of whom had dirt floors. CONCLUSIONS: Confounding presents a substantial problem for observational studies of indoor air pollution and health, although there is a reasonable case for believing that the observed association is causal. Intervention studies are required for stronger evidence of this association, and more importantly, to determine the size of health benefit achievable through feasible exposure reductions.

Adolescent↗
PubMed1976

Animal experiments with biogalvanic and biofuel cells.

Animal experiments with biogalvanic cells have demonstrated that an average power of 80 muW can be derived continously for at least 2 years. There is a further scope to stabilize the power at 100 muW for considerable longer periods so that the chances of cardiac pacing with biogalvanic power have become bright. However, large scale efforts are necessary in in establishing the statistical reliability and the secured performance which are expensive and time consuming. Animal experiments with biofuel cells are still in preliminary stages. We derived a continous power of 40 muW (4MUW/cm2) at 575 mV over 150 days so far. This is the longest recorded period with such a high power density. The main problem in deriving higher power over longer period is to properly encapsulate the cell with materials which are hydrophilic and essentially biocompatible.

Animals↗
PubMed1996

Physiologic studies with the sulfate-reducing bacterium Desulfovibrio desulfuricans: evaluation for use in a biofuel cell.

The growth kinetics of the sulfate-reducing bacteria Desulfovibrio desulfuricans Essex 6 was investigated under various conditions for potential use in a microbial fuel cell that recovers electrons generated from the reduction of sulfate to hydrogen sulfide. Hydrogen sulfide was found to inhibit growth and decrease both the growth yields and the sulfate-specific reduction rate. Hydrogen sulfide inhibition was direct, reversible, and not due to limitation by iron deficiency. A high initial lactate concentration also retarded bacterial growth, reduced the specific sulfate reduction rates, and gave variable biomass growth yields. This effect resulted from a bottleneck in the lactate oxidation pathway which induced the production of the secondary product butanol. The use of pyruvate as a carbon source was more advantageous than lactate in terms of growth rate and biomass growth yields, with only a slight decrease in the rate of specific sulfate reduction. For equal biomass, a slightly higher current density was generated from lactate than pyruvate, but pyruvate required nearly 40% less sulfate.

Biomass↗
PubMed2002

The design of dehydrogenase enzymes for use in a biofuel cell: the role of genetically introduced peptide tags in enzyme immobilization on electrodes.

The immobilization of the mutants of L-lactate dehydrogenase (LDH) on poly(aniline) (PANi) composite films has been investigated. Mutants possessing peptide tags of varying charge and nucleophilicity were created to probe the nature of the interaction between the protein and PANi. These results are significant for the development of a 'generic' approach to the immobilization of enzymes and other proteins.

Bioelectric Energy Sources↗