Analysis of microbial community structure and composition in leachates from a young landfill by 454 pyrosequencing

Abstract

Microorganisms are responsible for degrading the raw leachate generated in sanitary landfills, extracting the soluble fraction of the landfill waste and biotransforming organic matter and toxic residues. To increase our understanding of these highly contaminated ecosystems, we analyzed the microbial communities in the leachate produced by three landfill cells of different ages. Using high-throughput 454 pyrosequencing of the 16S rRNA gene, we describe the structure of the leachate communities and present their compositional characteristics. All three communities exhibited a high level of abundance but were undersampled, as indicated by the results of the rarefaction analysis. The distribution of the taxonomic operational units (OTUs) was highly skewed, suggesting a community structure with a few dominant members that are key for the degradation process and numerous rare microorganisms, which could act as a resilient microorganism seeder pool. Members of the phylum Firmicutes were dominant in all of the samples, accounting for up to 62% of the bacterial sequences, and their proportion increased with increasing landfill age. Other abundant phyla included Bacteroidetes, Proteobacteria, and Spirochaetes, which together with Firmicutes comprised 90% of the sequences. The data illustrate a microbial community that degrades organic matter in raw leachate in the early stages, before the methanogenic phase takes place. The genera found fit well into the classical pathways of anaerobic digestion processes.

Next-generation sequencing showing potential leachate influence on bacterial communities around a landfill in China

“…Municipal landfill waste compositions can range from food wastes to high-strength detergents, solvents and pharmacological products comprising a broad spectrum of xenobiotic and recalcitrant toxic compounds with potential harmful ecological impacts (Köchling et al, 2015, Song et al, 2015a. Although modern landfills in well-regulated economies are highly engineered and monitored, older or informal (unplanned, uncontrolled) landfills worldwide are sources of leachate which, unless correctly collected and treated, can cause serious reductions in the quality of water bodies and groundwater sources (Li et al, 2014, Zhang et al, 2013a.…”

Garlic Skin Induced Shifts in the Rumen Microbiome and Metabolome of Fattening Sheep

“…The raw reads containing ambiguous bases and any longer than 480 base pairs (bp) were dislodged and those with a maximum homopolymer length of 6 bp were allowed, and sequence short than 200 bp were removed [21].Paired-end raw reads were merged as raw tags using FLSAH (v 1.2.3) with a minimum overlap of 10 bp [22].Noisy sequences of raw tags were ltered by the Pre.cluster tool to obtain clean tags. Chimeras were detected by using Chimera UCHIME.…”

Garlic skin induced shifts in the rumen microbiome and metabolome of fattening sheep

“…The raw reads containing ambiguous bases and any longer than 480 base pairs (bp) were dislodged and those with a maximum homopolymer length of 6 bp were allowed, and sequence short than 200 bp were removed [52]. Paired-end raw reads were merged as raw tags using FLSAH (v 1.2.3) with a minimum overlap of 10 bp [53].…”