Analysis of a Methanogen and an Actinobacterium Dominating the Thermophilic Microbial Community of an Electromethanogenic Biocathode

Figure 2

FISH analysis of the microbial populations present on the cathode surfaces and in the supernatants of the cathode chambers. Alexa Fluor 488-labeled probes targeting the order Methanobacteriales (MB311) and Coriobacteriaceae sp. strain EMTCatB1 (B1_648) were used. SYTO59 was used for counterstaining. (a, b, e, f) Epifluorescent micrographs of two representative fields separately capturing the fluorescence of Alexa Fluor 488 (green) and SYTO59 (red) using the probes MB311 and B1_648, respectively (scale bar: 1.0 μm). (c, g) Stacked bar charts (100%) of the relative abundances of the cells with the Alexa Fluor 488 signal (green-colored stacks) and without the signal (gray-colored stacks) on the cathode surfaces. (d, h) Box and whisker plots of the cell lengths with the Alexa Fluor 488 signal (+) and without the signal (−). The number of counted/measured cells () is indicated at the top of the panels (c), (d), (g), and (h).