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

Area of Science:

• Microbiology
• Biotechnology
• Electrochemistry

Background:

• Thermophilic microorganisms capable of cellulose degradation and hydrogen production are of interest for bioenergy applications.
• Cow feces serve as a rich source for isolating such specialized microbial communities.

Purpose of the Study:

• To isolate and characterize hydrogen-producing thermophilic cellulolytic microorganisms from bovine sources.
• To evaluate the performance and stability of a hydrogenase-based enzymatic fuel cell (EFC) anode using hydrogen generated from microbial fermentation.

Main Methods:

• Isolation of thermophilic, cellulolytic microorganisms from cow feces.
• Measurement of cellulose hydrolysis and hydrogen production rates.
• Construction and operation of an enzymatic fuel cell (EFC) with a hydrogenase anode.
• Assessment of hydrogenase activity after prolonged exposure to a thermophilic fermentation environment.

Main Results:

• Successful isolation of hydrogen-producing thermophilic cellulolytic microorganisms.
• Observed rates of cellulose hydrolysis at 0.2 mM L(-1) h(-1) and hydrogen formation at 1 mM L(-1) h(-1).
• The hydrogenase anode in the EFC maintained 73% of its initial activity after 38 days (912 hours) of continuous operation under load.

Conclusions:

• Thermophilic microorganisms from cow feces are viable sources for hydrogen production.
• Enzymatic fuel cells utilizing hydrogenase anodes show promising stability and longevity for biohydrogen utilization.