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Turning cellulose waste into electricity: hydrogen conversion by a hydrogenase electrode.

Abramov SM, Sadraddinova ER, Shestakov AI, Voronin OG, Karyakin AA, Zorin NA, Netrusov AI - PLoS ONE (2013)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Biological Faculty of M.V. Lomonosov Moscow State University, Moscow, Russia.

ABSTRACT
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.

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Dependence of power output on overvoltage of the oxygen-hydrogen fuel cell combined with a bioreactor.The cultivation time of hydrogen-producing bacteria in the bioreactor cell was 38 days (25th day – black curve; 29th day – red curve; 34th day – green curve; 38th day – yellow curve, overpressure in the bioreactor – 0.5 atm, pH 6.7–7.0, 60 °C).
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pone-0083004-g006: Dependence of power output on overvoltage of the oxygen-hydrogen fuel cell combined with a bioreactor.The cultivation time of hydrogen-producing bacteria in the bioreactor cell was 38 days (25th day – black curve; 29th day – red curve; 34th day – green curve; 38th day – yellow curve, overpressure in the bioreactor – 0.5 atm, pH 6.7–7.0, 60 °C).

Mentions: The open circuit potential (OCP) was measured for 25 days after the start of cultivation (600 h; Figure 5). A slight drop of OCP from 750 to 650 mV was observed. Such a loss of activity (approx. 14%) correlates well with our previous data for electrodes incubated in microbial media without an electrical load (see 10). After 25 days (600 h) of cultivation, a constant electrical load was added. During the next 13 days (312 h) of cultivation, the power output decreased from 71 to 52 μW (approx. 27% loss of activity; black and yellow curves in Figure 6, respectively). A decrease of any enzyme electrode’s activity can be caused by three main factors: the effect of bacterial proteolytic exo-enzymes, desorption, and the destruction of the redox centre. It is well known that the hydrogenase from T. roseopersicina is rather resistant to proteolytic inactivation [16]. The loss of activity due to desorption should be invariable during an experiment, independent of whether the electrode operates with or without a load. Therefore, the key reason for the faster loss of activity during the second part of the experiment (14% after 25 days and 27% after 13 days) was high overvoltage. Such drop of activity in hydrogen oxidation at high overvoltages has been described for all known hydrogenases, even under the strict anaerobic conditions [17]. It is caused by oxidation of the Ni-SI state of the active site to the Ni-B state.


Turning cellulose waste into electricity: hydrogen conversion by a hydrogenase electrode.

Abramov SM, Sadraddinova ER, Shestakov AI, Voronin OG, Karyakin AA, Zorin NA, Netrusov AI - PLoS ONE (2013)

Dependence of power output on overvoltage of the oxygen-hydrogen fuel cell combined with a bioreactor.The cultivation time of hydrogen-producing bacteria in the bioreactor cell was 38 days (25th day – black curve; 29th day – red curve; 34th day – green curve; 38th day – yellow curve, overpressure in the bioreactor – 0.5 atm, pH 6.7–7.0, 60 °C).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3842985&req=5

pone-0083004-g006: Dependence of power output on overvoltage of the oxygen-hydrogen fuel cell combined with a bioreactor.The cultivation time of hydrogen-producing bacteria in the bioreactor cell was 38 days (25th day – black curve; 29th day – red curve; 34th day – green curve; 38th day – yellow curve, overpressure in the bioreactor – 0.5 atm, pH 6.7–7.0, 60 °C).
Mentions: The open circuit potential (OCP) was measured for 25 days after the start of cultivation (600 h; Figure 5). A slight drop of OCP from 750 to 650 mV was observed. Such a loss of activity (approx. 14%) correlates well with our previous data for electrodes incubated in microbial media without an electrical load (see 10). After 25 days (600 h) of cultivation, a constant electrical load was added. During the next 13 days (312 h) of cultivation, the power output decreased from 71 to 52 μW (approx. 27% loss of activity; black and yellow curves in Figure 6, respectively). A decrease of any enzyme electrode’s activity can be caused by three main factors: the effect of bacterial proteolytic exo-enzymes, desorption, and the destruction of the redox centre. It is well known that the hydrogenase from T. roseopersicina is rather resistant to proteolytic inactivation [16]. The loss of activity due to desorption should be invariable during an experiment, independent of whether the electrode operates with or without a load. Therefore, the key reason for the faster loss of activity during the second part of the experiment (14% after 25 days and 27% after 13 days) was high overvoltage. Such drop of activity in hydrogen oxidation at high overvoltages has been described for all known hydrogenases, even under the strict anaerobic conditions [17]. It is caused by oxidation of the Ni-SI state of the active site to the Ni-B state.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Biological Faculty of M.V. Lomonosov Moscow State University, Moscow, Russia.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus