Enrichment and Isolation of CO 2 -Fixing Bacteria with Electrochemical Reducing Power as a Sole Energy Source

Abstract

Enrichment of bacteria capable of growing with electrochemical reducing power and CO2 was accomplished using a plate-type electrochemical bioreactor (PEB). A bacterial source obtained from wastewater treatment reactant and forest soil was cultivated on carbonate-based mineral agar medium prepared in the PEB (PEB-carbonate agar). According to the pyrosequencing analyses, the abundance of Betaproteobacteria and Gammaproteobacteria at the phylum level, and Achromobacter, Alcaligenes, and Pseudomonas at the genus level were selectively increased after the electrochemical enrichment culture. Finally, one genus of bacterium that was autotrophically grown on the PEB-carbonate agar was identified as Alcaligenes. This bacterium may be useful to fix atmospheric CO2 with electrochemical energy obtained from the solar cell.