초록
<P><B>Abstract</B></P> <P>This study evaluated the effect of temperature on methane production by CO<SUB>2</SUB> reduction during microbial electrosynthesis (MES) with a mixed-culture biocathode. Reactor performance, in terms of the amount and rate of methane production, current density, and coulombic efficiency, was compared at different temperatures. The microbial properties of the biocathode at each temperature were also analyzed by 16S rRNA gene sequencing. The results showed that the optimum temperature for methane production from CO<SUB>2</SUB> reduction in MES with a mixed-culture cathode was 50°C, with the highest amount and rate of methane production of 2.06±0.13mmol and 0.094±0.01mmolh<SUP>−1</SUP>, respectively. In the mixed-culture biocathode MES, the coulombic efficiency of methane formation was within a range of 19.15±2.31% to 73.94±2.18% due to by-product formation at the cathode, including volatile fatty acids and hydrogen. Microbial analysis demonstrated that temperature had an impact on the diversity of microbial communities in the biofilm that formed on the MES cathode. Specifically, the hydrogenotrophic methanogen <I>Methanobacterium</I> became the predominant archaea for methane production from CO<SUB>2</SUB> reduction, while the abundance of the aceticlastic methanogen <I>Methanosaeta</I> decreased with increased temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of temperature on CH<SUB>4</SUB> production in MES was evaluated. </LI> <LI> Optimum temperature was 50°C for CH<SUB>4</SUB> production with a mixed-culture cathode. </LI> <LI> Coulombic efficiency of CH<SUB>4</SUB> production was within a range of 19.15% to 73.94%. </LI> <LI> Temperature significantly affected the microbial communities on the biocathode. </LI> <LI> <I>Methanobacterium</I> became the predominant methanogen at elevated temperatures. </LI> </UL> </P>