Project description:We established simple synthetic microbial communities in a microcosm model system to determine the mechanisms that underlay cross-feeding in microbial methane-consuming communities. Co-occurring strains from Lake Washington sediment were used that are involved in methane consumption, a methanotroph and two non-methanotrophic methylotrophs.
Project description:Anthropogenic activities such as urbanization and agriculture can potentially pose a threat to neighboring freshwaters through nitrate and phosphorous contamination, which over time may lead to lake eutrophication. In such nitrogen-polluted environments, oxygen is depleted, and plants die and decompose. This enhances denitrifying microbes that respire under hypoxic/anoxic conditions by reducing nitrate instead of molecular oxygen and using plant remnants (lignocellulose) as carbon source. Microbial lignocellulose degradation has been well-studied for both aerobic- and anaerobic conditions; however, its degradation during denitrification remains largely unknown. Here we have applied a combination of gas kinetics and meta-omics techniques to enrich and analyze microbial communities from 10 eutrophic lakes to identify a set of core microbial metagenome-assembled genomes (MAGs) present in all the eutrophic lakes. We have further investigated their strategies and enzyme profiles for degrading lignocellulose under denitrifying conditions. We identified Pseudomonadota, Bacteroidota, Verrucomicrobiota, and Actinomycetota as the most abundant phyla and they were present in enrichments from all eutrophic lakes having a key role in denitrification and fermentation. Lignocellulose degradation was, however, dominated by species outside the core microbiome, i.e., there were differing key degraders between lakes, suggesting some level of lake-specialization. Among these we observed potential respiratory DNRA pathways, and they expressed a broad range of CAZymes targeting the various lignocellulose subfractions. Interestingly, many of the detected MAGs contained NO dismutases, enzymes postulated to convert NO to molecular oxygen and dinitrogen gas.
Project description:Here, we applied a microarray-based metagenomics technology termed GeoChip 5.0 to investigate spring microbial functional genes in mesocosm-simulated shallow lake ecosystems having been undergoing nutrient enrichment and warming for nine years.
2020-12-30 | GSE155582 | GEO
Project description:Enrichment of methanogens from Basque Lake, Canada
Project description:Four stable and robust TCE-dechlorinating microbial communities were enriched from TCE-contaminated groundwater under four different conditions exploring two parameters, high and low methanogenic activity (Meth and NoMeth), with and without vitamin B12 supplement (MethB12 and NoMethB12, Meth and NoMeth, respectively). Identical amounts of lactate (2.7 mmol) and TCE (20 μl) were supplied as electron donor and electron acceptor. All four cultures were capable of reductively dechlorinating TCE to VC and ethene. Genomic DNA of the four enrichments was applied on a quad-Dhc-genome microarray in order to characterize the gene content of Dehalococcoides species present in the four enrichments
