Oleg G. Voronin

Turning Cellulose Waste Into Electricity: Hydrogen Conversion by a Hydrogenase Electrode

Hydrogen-producing thermophilic cellulolytic microorganisms were isolated from cow faeces. Rates of cellulose hydrolysis and hydrogen formation were 0.2 mM L-1 h-1 and 1 mM L-1 h-1, respectively. An enzymatic fuel cell (EFC) with a hydrogenase anode was used to oxidise hydrogen produced in a microbial bioreactor. The hydrogenase electrode was exposed for 38 days (912 h) to a thermophilic fermentation medium. The hydrogenase activity remaining after continuous operation under load was 73% of the initial value.

Ultramicrosensors based on transition metal hexacyanoferrates for scanning electrochemical microscopy

Summary We report here a way for improving the stability of ultramicroelectrodes (UME) based on hexacyanoferrate-modified metals for the detection of hydrogen peroxide. The most stable sensors were obtained by electrochemical deposition of six layers of hexacyanoferrates (HCF), more specifically, an alternating pattern of three layers of Prussian Blue and three layers of Ni–HCF. The microelectrodes modified with mixed layers were continuously monitored in 1 mM hydrogen peroxide and proved to be stable for more than 5 h under these conditions. The mixed layer microelectrodes exhibited a stability which is five times as high as the stability of conventional Prussian Blue-modified UMEs. The sensitivity of the mixed layer sensor was 0.32 A·M−1·cm−2, and the detection limit was 10 µM. The mixed layer-based UMEs were used as sensors in scanning electrochemical microscopy (SECM) experiments for imaging of hydrogen peroxide evolution.

Foundations of a technology for the microbiological conversion of organic cellulose-containing wastes into electrical energy through the intermediate formation of biohydrogen

The screening of microorganisms that are able to degrade cellulose-containing wastes and release hydrogen release was performed. The foundations of a technology for the removal and utilization of hydrogen were established. Classic microbiological techniques were used in the screening. The technology of polymer nonporous membranes was used to remove the hydrogen from the culture liquid. The obtained hydrogen was constantly oxidized with the formation of electricity, using the innovative technology of a fermentation electrode based on hydrogenase. In the course of our work, several highly productive biocenoses of microorganisms were selected; the possibility of raising the microbiological conversion of cellulose-containing wastes into electrical energy from 20 mM(H2)/(l h) to 68 mM(H2)/(l h) through the formation of hydrogen and the application of membrane technology was shown; and the possibility of using the fermentation fuel electrode for the oxidation of hydrogen was demonstrated. The maximum capacity was increased to 250 μW/sm2. It was shown that both technologies can be used to produce electrical energy and absolutely pure hydrogen.