Effect of inoculum concentration on methanogenesis by direct interspecies electron transfer: Performance and microbial community composition. (November 2019)

• Record Type: Journal Article
• Authors: Kang, Hyun-Jin; Lee, Sang-Hoon; Lim, Tae-Guen; Park, Hee-Deung
• Is Part Of: Bioresource technology. Volume 291(2019)
• Publication Date: 2019-11
• Subjects: Inoculum concentration -- Direct interspecies electron transfer -- Anaerobic digester -- Geobacter species -- Enrichment; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2019.121881
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Low inoculum concentrations with GAC facilitated enhanced methane production. Geobacter species were enriched on GAC under low inoculum concentration conditions. Geobacter species may compete with aceticlastic methanogens on GAC surfaces. Enriched Geobacter enhanced methanogenesis by DIET under low inoculum concentrations. Abstract: To understand the effect of inoculum concentration on direct interspecies electron transfer (DIET) for methanogenesis, batch-type anaerobic bioreactors with different inoculum concentrations were operated with and without supplemented granular activated carbon (GAC). With decrease in inoculum concentration, GAC-supplemented bioreactors showed faster methane production rates and reduced lag times. Geobacter species were specifically enriched on the GAC surfaces under lower inoculum concentration conditions. Together, the relative abundance of aceticlastic methanogens (competitors of Geobacter species for acetate) gradually decreased when the inoculum concentration increased. These results suggested that the specific enrichment of Geobacter species by outcompeting with aceticlastic methanogens through low inoculum concentrations on GAC surfaces accelerated methanogenesis by DIET via GAC in anaerobic bioreactors. Taken together, the results of this study suggested that inoculum concentration is an important factor in stimulating DIET for methane production.