A heterologously-expressed thermostable Pyrococcus furiosus cytoplasmic [NiFe]-hydrogenase I used as the catalyst of H2/air biofuel cells

Hydrogenase-catalyzed H-2/air biofuel cells have attracted wide attention. However, how to obtain thermostable and highly active hydrogenase remains challenging. Herein, we developed a thermophilic archaea host system to heterologously express a thermostable Pyrococcus furiosus cytoplasmic [NiFe]-hydrogenase I (PfSHI). The recombinant hydrogenase could be easily isolated and then immobilized onto a carbon nanotube-modified carbon felt electrode for further electrochemical characterization. The bioanode was able to work at a wide range of temperatures from 40 degrees C to 80 degrees C and no high potential deactivation was observed until 0.3 V at 50 degrees C. Cyclic voltammograms at elevated temperatures for reverse H-2 oxidation performance indicated that an inactive state might be formed and then reversed when scanning to negative position. Also, the power density of a whole cell reached 1.08 mW cm(-2) using Pt/C as the cathode with a brilliant open circuit potential reaching 1.2 V. The voltage could retain 90% of its initial value after 33 h discharge at a current of 10 mu A. Besides, the bioanode exhibited decent oxygen tolerance both in ambient and elevated temperatures. These results suggest that this recombinant PfSHI can be a good candidate for catalyzing H-2/air biofuel cells. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A thermophilic archaea host system was developed to express a thermostable Pyrococcus furiosus cytoplasmic [NiFe]-hydrogenase I, which showed high activity and stability at elevated temperatures. The recombinant hydrogenase could be a good candidate for catalyzing H-2/air biofuel cells, with promising electrochemical performance and oxygen tolerance.