Genome-centric metagenomics provides new insights into the microbial community and metabolic potential of landfill leachate microbiota

Author(s):  
Chunfang Deng ◽  
Renxin Zhao ◽  
Zhiguang Qiu ◽  
Bing Li ◽  
Tong Zhang ◽  
...  
2021 ◽  
Vol 12 ◽  
Author(s):  
Shohei Yasuda ◽  
Toshikazu Suenaga ◽  
Laura Orschler ◽  
Shelesh Agrawal ◽  
Susanne Lackner ◽  
...  

Upcycling wastes into valuable products by mixed microbial communities has recently received considerable attention. Sustainable production of high-value substances from one-carbon (C1) compounds, e.g., methanol supplemented as an external electron donor in bioreactors for wastewater treatment, is a promising application of upcycling. This study undertook a gene-centric approach to screen valuable production potentials from mixed culture biomass, removing organic carbon and nitrogen from landfill leachate. To this end, the microbial community of the activated sludge from a landfill leachate treatment plant and its metabolic potential for the production of seven valuable products were investigated. The DNA extracted from the activated sludge was subjected to shotgun metagenome sequencing to analyze the microbial taxonomy and functions associated with producing the seven products. The functional analysis confirmed that the activated sludge could produce six of the valuable products, ectoine, polyhydroxybutyrate (PHB), zeaxanthin, astaxanthin, acetoin, and 2,3-butanediol. Quantification of the detected functional gene hit numbers for these valuable products as a primary trial identified a potential rate-limiting metabolic pathway, e.g., conversion of L-2,4-diaminobutyrate into N-γ-acetyl-L2,4,-diaminobutyrate during the ectoine biosynthesis. Overall, this study demonstrated that primary screening by the proposed gene-centric approach can be used to evaluate the potential for the production of valuable products using mixed culture or single microbe in engineered systems. The proposed approach can be expanded to sites where water purification is highly required, but resource recovery, or upcycling has not been implemented.


2019 ◽  
Author(s):  
Luz Breton-Deval ◽  
Ayixon Sanchez-Reyes ◽  
Alejandro Sánchez-Flores ◽  
Katy Juárez ◽  
Patricia Mussali-Galante

ABSTRACTThe objective of this study is to understand the functional potential of the microbial community related to bioremediation activity and its relationship with the pollution of each site to enhance the future design of more accurate bioremediation processes. Water samples were collected at four sampling sites along the Apatlaco River (S1-S4), and a whole metagenome shotgun sequencing was performed to know and understand the microbial community involved in bioremediation. Additionally, HMMER was used for searching sequence homologs related to PET and polystyrene biodegradation and metal transformation in Apatlaco River metagenomes. The Apatlaco River is characterized by the presence of a broad spectrum of microorganisms with the metabolic potential to carry out bioremediation activities. Every site along the Apatlaco River has a particular community to perform bioremediation activities. The first site S1 has Thiomonas, Polaromonas, Pedobacter, and Myroides, S2 has Pedobacter, Myroides, Pseudomonas and Acinetobacter, S3, Thiomonas, Myroides, Pseudomonas, Acinetobacter and Aeromonas; S4, Thiomonas, Myroides and Pseudomonas, Thauera.Furthermore, every site is rich in specific enzymes such as S1 has dioxygenase and dehydrogenase, which can degrade Catechol, Biphenyl, Naphthalene, and Phthalate. While, S2 and S3 are rich in dioxygenase and decarboxylating dehydrogenases to degrade Toluene, Fluorobenzoate, Xylene, Phenylpropanoate, and Phenol. S3 also has monooxygenases which degrade Benzene, and all the earlier mentioned enzymes were also found at S4.


2020 ◽  
Author(s):  
Olivia U. Mason ◽  
Patrick Chanton ◽  
Loren N. Knobbe ◽  
Julian Zaugg ◽  
Behzad Mortazavi

AbstractCoastal salt marshes are some of the most productive ecosystems on Earth, providing numerous services such as soil carbon storage, flood protection and nutrient filtering, several of which are mediated by the sediment microbiome associated with marsh vegetation. Here, nutrient filtering (nitrate removal through denitrification) was examined by determining microbial community structure (16S rRNA gene iTag sequencing), diversity, denitrification rates and metabolic potential (assembled metagenomic sequences) in collocated patches of Spartina alterniflora (Spartina) and Juncus roemerianus (Juncus) sediments. The iTag data showed that diversity and richness in Spartina and Juncus sediment microbial communities were highly similar. However, microbial community evenness differed significantly, with the most even communities observed in Juncus sediments. Further, denitrification rates were significantly higher in Juncus compared to Spartina, suggesting oscillations in microbial abundances and in particular the core microbiome identified herein, along with plant diversity influence marsh nitrogen (N) removal. Amplicon and assembled metagenome sequences pointed to a potentially important, yet unappreciated Planctomycetes role in N removal in the salt marsh. Thus, perturbations, such as sea-level rise, that can alter marsh vegetation distribution could impact microbial diversity and may ultimately influence the ecologically important ecosystem functions the marsh sediment microbiome provides.


mSystems ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Nunzia Picone ◽  
Carmen Hogendoorn ◽  
Geert Cremers ◽  
Lianna Poghosyan ◽  
Arjan Pol ◽  
...  

ABSTRACT Volcanic and geothermal environments are characterized by low pH, high temperatures, and gas emissions consisting of mainly CO2 and varied CH4, H2S, and H2 contents which allow the formation of chemolithoautotrophic microbial communities. To determine the link between the emitted gases and the microbial community composition, geochemical and metagenomic analysis were performed. Soil samples of the geothermic region Favara Grande (Pantelleria, Italy) were taken at various depths (1 to 50 cm). Analysis of the gas composition revealed that CH4 and H2 have the potential to serve as the driving forces for the microbial community. Our metagenomic analysis revealed a high relative abundance of Bacteria in the top layer (1 to 10 cm), but the relative abundance of Archaea increased with depth from 32% to 70%. In particular, a putative hydrogenotrophic methanogenic archaeon, related to Methanocella conradii, appeared to have a high relative abundance (63%) in deeper layers. A variety of [NiFe]-hydrogenase genes were detected, showing that H2 was an important electron donor for microaerobic microorganisms in the upper layers. Furthermore, the bacterial population included verrucomicrobial and proteobacterial methanotrophs, the former showing an up to 7.8 times higher relative abundance. Analysis of the metabolic potential of this microbial community showed a clear capacity to oxidize CH4 aerobically, as several genes for distinct particulate methane monooxygenases and lanthanide-dependent methanol dehydrogenases (XoxF-type) were retrieved. Analysis of the CO2 fixation pathways showed the presence of the Calvin-Benson-Bassham cycle, the Wood-Ljungdahl pathway, and the (reverse) tricarboxylic acid (TCA) cycle, the latter being the most represented carbon fixation pathway. This study indicates that the methane emissions in the Favara Grande might be a combination of geothermal activity and biological processes and further provides insights into the diversity of the microbial population thriving on CH4 and H2. IMPORTANCE The Favara Grande nature reserve on the volcanic island of Pantelleria (Italy) is known for its geothermal gas emissions and high soil temperatures. These volcanic soil ecosystems represent “hot spots” of greenhouse gas emissions. The unique community might be shaped by the hostile conditions in the ecosystem, and it is involved in the cycling of elements such as carbon, hydrogen, sulfur, and nitrogen. Our metagenome study revealed that most of the microorganisms in this extreme environment are only distantly related to cultivated bacteria. The results obtained profoundly increased the understanding of these natural hot spots of greenhouse gas production/degradation and will help to enrich and isolate the microbial key players. After isolation, it will become possible to unravel the molecular mechanisms by which they adapt to extreme (thermo/acidophilic) conditions, and this may lead to new green enzymatic catalysts and technologies for industry.


2018 ◽  
Vol 249 ◽  
pp. 108-116 ◽  
Author(s):  
Lei Miao ◽  
Qiong Zhang ◽  
Shuying Wang ◽  
Baikun Li ◽  
Zhong Wang ◽  
...  

2011 ◽  
Vol 77 (7) ◽  
pp. 2264-2274 ◽  
Author(s):  
Ji Young Jung ◽  
Se Hee Lee ◽  
Jeong Myeong Kim ◽  
Moon Su Park ◽  
Jin-Woo Bae ◽  
...  

ABSTRACTKimchi, a traditional food in the Korean culture, is made from vegetables by fermentation. In this study, metagenomic approaches were used to monitor changes in bacterial populations, metabolic potential, and overall genetic features of the microbial community during the 29-day fermentation process. Metagenomic DNA was extracted from kimchi samples obtained periodically and was sequenced using a 454 GS FLX Titanium system, which yielded a total of 701,556 reads, with an average read length of 438 bp. Phylogenetic analysis based on 16S rRNA genes from the metagenome indicated that the kimchi microbiome was dominated by members of three genera:Leuconostoc,Lactobacillus, andWeissella. Assignment of metagenomic sequences to SEED categories of the Metagenome Rapid Annotation using Subsystem Technology (MG-RAST) server revealed a genetic profile characteristic of heterotrophic lactic acid fermentation of carbohydrates, which was supported by the detection of mannitol, lactate, acetate, and ethanol as fermentation products. When the metagenomic reads were mapped onto the database of completed genomes, theLeuconostoc mesenteroidessubsp.mesenteroidesATCC 8293 andLactobacillus sakeisubsp.sakei23K genomes were highly represented. These same two genera were confirmed to be important in kimchi fermentation when the majority of kimchi metagenomic sequences showed very high identity toLeuconostoc mesenteroidesandLactobacillusgenes. Besides microbial genome sequences, a surprisingly large number of phage DNA sequences were identified from the cellular fractions, possibly indicating that a high proportion of cells were infected by bacteriophages during fermentation. Overall, these results provide insights into the kimchi microbial community and also shed light on fermentation processes carried out broadly by complex microbial communities.


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