Biogas‐producing microbial composition of an anaerobic digester and associated bovine residues

Abstract

Influenced by feedstock type and microbial inoculum, different microbial groups must precisely interact for high‐quality biogas yields. As a first approach for optimization, this study aimed to identify through time the biogas‐producing microbial community in a 10‐ton dry anaerobic digester treating cattle manure by denaturing gradient gel electrophoresis (DGGE) and metagenomics. Moreover, the associated bovine residues or feedstocks (leachate, manure, oxidation lagoon water, rumen) were also characterized to determine their contribution. A diverse and dynamic community characterized by Bacteria (82%–88%) and a considerable amount of Archaea (8%–15%) presented profiles particular to each stage of biogas production. Eukaryotes (2.6%–3.6%), mainly fungi, were a minor but stable component. Proteobacteria represented 47% of the community at the start of the run but only 18% at the end, opposite to the Bacteroidetes/Chlorobi group (8% and 20%, respectively), while Firmicutes (12%–18%) and Actinobacteria (12%–32%) remained relatively constant. Methanogens of the order Methanomicrobiales represented by several species of Methanoculleus were abundant at the end of the run (77%) contrary to Methanosarcinales (11%) and Methanobacteriales (0.7%). Therefore, methanogenesis mainly occurred by the hydrogenotrophic pathway. Manure and oxidation lagoon water seemed to contribute key microorganisms, while rumen dominated by Methanobrevibacter (72%) did not proliferate in the digester. Manure particularly possessed Methanoculleus (24%) and uncultured methanogens identified by DGGE, whereas oxidation lagoon was exclusively abundant in Methanolinea (18%) and Methanosaeta (19%). Leachate, as the microbial inoculum from a previous run, adequately preserved the biogas‐producing community. These results could lead to higher biogas yields through bioaugmentation strategies by incorporating higher proportions or an enriched inoculum from the relevant feedstocks.

The Role of Petrimonas mucosa ING2-E5AT in Mesophilic Biogas Reactor Systems as Deduced from Multiomics Analyses

“…Petrimonas members were also detected in microbiomes originating from a pilot-scale dry anaerobic digester fed with residual biomass from the bovine husbandry (64.2% manure, 18.2% oxidation lagoon water, 3% fresh rumen fluid, 9.6% wood chips, 4.0% corn stover, and 0.9% dust mill) and operated under mesophilic conditions [ 80 ]. Interestingly, the highest number of sequences assigned to the P. mucosa genome in this reactor (2.87% of all metagenome sequences) was detected a short time after a process disturbance that occurred due to a pump failure during leachate recirculation.…”

Fabrication and Optimization of Nanocatalyst for Biodiesel Production: An Overview

“…under anaerobic conditions (Kana et al, 2012). Various other gases are also produced which can be further used in different synthesis processes (Li et al, 2020;Senés-Guerrero et al, 2019). In comparison to their bulk counterparts, nanomaterials with excellent structural and morphological properties significantly enhance the methane production.…”

Viscosity and Total Organic Carbon Removal in High-Solid Anaerobic Digestion of Sewage Sludge

“…Pretreatment at high temperatures disinfects the sludge and degrades the extracellular polymeric substances (EPS) inside as well as on the face of the flocs, dissolving the floc structure and enhancing the bioavailability of the materials that make up the cells as well as SS dewaterability. Furthermore, cell damage caused by pressure variations during the thermal process may lead to an improvement in the rate of degradation [17], [18]. For AD improvement, low-temperature pretreatment uses temperatures below 100 °C.…”