Simultaneous intensification of direct acetate cleavage and CO2 reduction to generate methane by bioaugmentation and increased electron transfer

Publication date: 15 December 2019Source: Chemical Engineering Journal, Volume 378Author(s): Leilei Xiao, Ran Sun, Peng Zhang, Shiling Zheng, Yang Tan, Jiajia Li, Yuechao Zhang, Fanghua LiuAbstractDirect interspecies electron transfer coupled to CO2 reduction, DIET-CO2 reduction, to generate methane is proposed and prosperous in 2010s. It is well known that bioaugmentation and increased electron transfer benefit DIET-CO2 reduction. Herein, we studied whether other methanogenic pathways, such as H2-mediated methanogenic progress and direct acetate cleavage (acetoclastic methanogenesis), are simultaneously favorable in the presence of conductive materials (CMs). If so, contribution of DIET-CO2 reduction may be overestimated because overwhelming studies just considered this pathway. Detailed researches on whether and how Clostridium pasteurianum coupled with CMs, granular activated carbon, biochar, nano-magnetite and grapheme, influenced methanogenic progresses were conducted. Overall, C. pasteurianum enhanced methane production rate, which was further improved by some CMs. Combined with metabolism, kinetic and electrochemical analysis, experimental results showed that hydrogenotrophic methanogenesis occurred and bioaugmentation strengthened this progress, which was further motivated by CMs, such as biochar and magnetite. 16S rRNA gene analysis suggested that Methanobacteriaceae was potentially responsible for methane production. Whereafter, DIET-CO2 reduction may become prosper...

Source: Chemical Engineering Journal - July 19, 2019 Category: Chemistry Source Type: research