Methane production from formate, acetate and H2/CO2; focusing on kinetics and microbial characterization

• Published in: Bioresource technology 2016-10, Vol.218, p.796-806
• Main Authors: Pan, Xiaofang, Angelidaki, Irini, Alvarado-Morales, Merlin, Liu, Houguang, Liu, Yuhong, Huang, Xu, Zhu, Gefu
• Format: Article
• Language: English
• Subjects: Acetates - chemistry; Acetates - metabolism; Anaerobic digestion; Bioreactors - microbiology; Carbon Dioxide - chemistry; Carbon Dioxide - metabolism; Formates - chemistry; Formates - metabolism; Hydrogen - chemistry; Hydrogen - metabolism; Kinetics; Methane - analysis; Methane - chemistry; Methane - metabolism; Methanogenic precursors; Methanomicrobiales - chemistry; Methanomicrobiales - metabolism; Microbial analysis; Modified Gompertz model; Sewage - microbiology
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.07.032

•Methanation rates of formate, acetate and H2/CO2 in mixed cultures were compared.•Modified Gompertz model was applied for kinetic parameters prediction (R2>0.96).•Formate had a higher consumption rate than H2/CO2 in granular sludge system.•Abundance of Methanobacteriales contributed to rapid formate consumption.•Granular aggregate structure resulted in low degradation of acetate and H2/CO2. For evaluating the methanogenesis from typical methanogenic precursors (formate, acetate and H2/CO2), CH4 production kinetics were investigated at 37±1°C in batch anaerobic digestion tests and stimulated by modified Gompertz model. The results showed that maximum methanation rate from formate, acetate and H2/CO2 were 19.58±0.49, 42.65±1.17 and 314.64±3.58NmL/gVS/d in digested manure system and 6.53±0.31, 132.04±3.96 and 640.16±19.92NmL/gVS/d in sewage sludge system during second generation incubation. Meanwhile the model could not fit well in granular sludge system, while the rate of formate methanation was faster than from H2/CO2 and acetate. Considering both the kinetic results and microbial assay we could conclude that H2/CO2 methanation was the fastest methanogenic step in digested manure and sewage sludge system with Methanomicrobiales as dominant methanogens, while granular sludge with Methanobacteriales as dominant methanogens contributed to the fastest formate methanation.