Project description:Key questions: • Are hydrolysis fermenters useful for the biogas process? • How redundant are the different functions? • Does the function of MAGs differ in the different fermenters? • Which depencies exist (transporters vs. producers?), antimicrobial genes, antibiotic resistencies,phages-hosts? • Can we quantify the biomass turnover? • Can we find new pathways for SAO and Methanogenesis? • How active are the MAGs?
Project description:Deeply sequenced metagenome and metatranscriptome of a biogas-producing microbial community from an agricultural production-scale biogas plant
Project description:Anaerobic degradation (AD) of heterogeneous agricultural substrates is a complex process involving a diverse microbial community. While microbial community composition of a variety of biogas plants (BPs) is well described, little is known about metabolic processes and microbial interaction patterns. Here, we analyzed 16 large-scale BPs using metaproteomics. All metabolic steps of AD were observed in the metaproteome, and multivariate analyses indicated that they were shaped by temperature, pH, volatile fatty acid content and substrate types. Biogas plants can be subdivided into hydrogenotrophic, acetoclastic or a mixture of both methanogenic pathways based on their process parameters, taxonomic and functional metaproteome. Network analyses showed large differences in metabolic and microbial interaction patterns. Both, number of interactions and interaction partners were highly dependent on the prevalent methanogenic pathway for most species. Nevertheless, we observed a highly conserved metabolism of different abundant Pseudomonas spp. for all BPs indicating a key role during AD in carbohydrate hydrolysis irrespectively of variabilities in substrate input and process parameters. Thus, Pseudomonas spp. are of high importance for robust and versatile AD food webs, which highlight a large variety of downstream metabolic processes for their respective methanogenic pathways.
Project description:Meta-proteomics analysis approach in the application of biogas production from anaerobic digestion has many advantages that has not been fully uncovered yet. This study aims to investigate biogas production from a stable 2-stage chicken manure fermentation system in chemical and biological perspective. The diversity and functional protein changes from the 1st stage to 2nd stage is a good indication to expose the differential metabolic processes in anaerobic digestion. The highlight of identified functional proteins explain the causation of accumulated ammonia and carbon sources for methane production. Due to the ammonia stress and nutrient limitation, the hydrogenotrophic methanogenic pathway is adopted as indicative of meta-proteomics data involving the key methanogenic substrates (formate and acetate). Unlike traditional meta-genomic analysis, this study could provide both species names of microorganism and enzymes to directly point the generation pathway of methane and carbon dioxide in investigating biogas production of chicken manure.
Project description:The functional diversity of soil microbial communities was explored for a poplar plantation, which was treated solely with biogas slurry, or combined with biochar at different fertilization intensities over several years.
Project description: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.
Project description:BACKGROUND:Decomposition of biomass for biogas production can be practiced under wet and dry fermentation conditions. In contrast to the dry fermentation technology, wet fermentation is characterized by a high liquid content and a relatively low total solid content. In this study, the composition and functional potential of a biogas-producing microbial community in an agricultural biogas reactor operating under wet fermentation conditions was analyzed by a metagenomic approach applying 454-pyrosequencing. The obtained metagenomic dataset and corresponding 16S rRNA gene amplicon sequences were compared to the previously sequenced comparable metagenome from a dry fermentation process, meeting explicitly identical boundary conditions regarding sample and community DNA preparation, sequencing technology, processing of sequence reads and data analyses by bioinformatics tools. RESULTS:High-throughput metagenome sequencing of community DNA from the wet fermentation process applying the pyrosequencing approach resulted in 1,532,780 reads, with an average read length of 397 bp, accounting for approximately 594 million bases of sequence information in total. Taxonomic comparison of the communities from wet and dry fermentation revealed similar microbial profiles with Bacteria being the predominant superkingdom, while the superkingdom Archaea was less abundant. In both biogas plants, the bacterial phyla Firmicutes, Bacteroidetes, Spirochaetes and Proteobacteria were identified with descending frequencies. Within the archaeal superkingdom, the phylum Euryarchaeota was most abundant with the dominant class Methanomicrobia. Functional profiles of the communities revealed that environmental gene tags representing methanogenesis enzymes were present in both biogas plants in comparable frequencies. 16S rRNA gene amplicon high-throughput sequencing disclosed differences in the sub-communities comprising methanogenic Archaea between both processes. Fragment recruitments of metagenomic reads to the reference genome of the archaeon Methanoculleus bourgensis MS2(T) revealed that dominant methanogens within the dry fermentation process were highly related to the reference. CONCLUSIONS:Although process parameters, substrates and technology differ between the wet and dry biogas fermentations analyzed in this study, community profiles are very similar at least at higher taxonomic ranks, illustrating that core community taxa perform key functions in biomass decomposition and methane synthesis. Regarding methanogenesis, Archaea highly related to the type strain M. bourgensis MS2(T) dominate the dry fermentation process, suggesting the adaptation of members belonging to this species to specific fermentation process parameters.