To study the microbial community change with different substrate and different added conductive materials in anaerobic digestion.

Recently, the addition of conductive materials (CMs) into anaerobic digestion has been receiving many attention as it could improve the methane production rate through the direct interspecies electron transfer (DIET) mechanism. Although many DIET via CM have been studied to date, studies on direct comparison with different CMs under the same experimental condition are limited. Furthermore, it is unclear whether all substrates are suitable for cultivating DIET-related microbes. Therefore, the objective of this project is to elucidate the effect of substrates (ethanol vs. sodium propionate) in cultivating DIET-related microbes, as well as how the addition of different conductive materials (granular activated carbon (GAC), multi-walled carbon nanotube (MWCNT), polyaniline (PANI)) could stimulate the growth of DIET-related microbes and change in the microbial community. Sludge was sampled before and after the experiment for all conditions, then 16S rRNA gene transcript-based amplicon sequencing was used to analyze the microbial community structure.