Bacterial community diversity in municipal waste landfill sites

Abstract

Little is known about the bacterial diversity of landfills and how environmental factors impact the diversity. In this study, PCR-based 454 pyrosequencing was used to investigate the bacterial communities of ten landfill leachate samples from five landfill sites in China. A total of 137 K useable sequences from the V3-V6 regions of the 16S rRNA gene were retrieved from 205 K reads. These sequences revealed the presence of a large number of operational taxonomic units (OTUs) in the landfills (709-1599 OTUs per sample). The most predominant bacterial representatives in the landfills investigated, regardless of geographic area, included Gammaproteobacteria, Firmicutes, and Bacteroidetes. The phyla Fusobacteria and Tenericutes were also found for the first time to be predominant in the landfills. The phylum Fusobacteria predominated (51.5 and 48.8%) in two semi-arid landfills, and the phylum Tenericutes dominated (30.6%) at one humid, subtropical landfill. Further, a large number of Pseudomonas was detected in most samples, comprising the dominant group and accounting for 40.9 to 92.4% of the total abundance. Principal component analysis (PCA) and cluster analysis based on OTU abundance showed that the abundant taxa separated the bacterial community. Canonical correlation analysis (CCA) suggested that precipitation and landfilling age significantly impact on the bacterial community structure. The bacterial community function (e.g., cellulolytic bacteria, sulfate-reducing bacteria (SRB), sulfate-oxidizing bacteria, and xenobiotic organic compound (XOC)-degrading bacteria) was also diverse, but the pattern is unclear.

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

“…The pH of leachate samples RL and FL2 were 7.78 and 8.12, respectively (Table 2). This range of pH has been reported in other landfill leachate studies conducted in China (Song et al, 2015a, D r a f t Song et al, 2015b, Li et al, 2014. Since this landfill has an onsite incinerator, the alkaline pH could be attributed to the disposal of ash in the landfill.…”

“…Leachate samples RL and FL2 had the least diverse phyla detection, in contrast to other landfill leachate studies (Song et al, 2015a, Wang et al, 2017. The high concentration of As and Hg in RL and FL2 could have inhibited the growth of other phyla, whereas Pseudomonas spp.…”

“…Previous studies on heavy metal influence towards microbial communities were performed using PCR-DGGE and GS 454 FLX pyrosequencing (Muller et al, 2001, Yao et al, 2017, Vishnivetskaya et al, 2011. Next generation sequencing (NGS) methods can assist in the identification of very rare taxa in the landfill samples (Köchling et al, 2015, Song et al, 2015a. NGS provides efficient, multiple level details of the operational taxonomical units (OTUs), richness and diversity, so it can be used to identify both similarities and differences between sites.…”

“…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.…”

Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

“…23,45,48 An adequate equilibrium between syntrophic bacteria and methanogens promotes CH 4 production because this relationship is essential to maintain nontoxic concentrations of VFAs and H 2 that affect both microbial groups. 50 Desulfomicrobium and Desulfovibrio are sulfate-reducing bacteria that play an important role in organic matter recycling and produce H 2 S. 36 Rhizobium, Luteimonas and Rhodococcus are usually found in landfills and contribute to the removal of toxic waste products such as aromatic compounds, promoting CH 4 production. 45,51 In addition, a methanotroph of the genus Methylocaldum and pathogens such as Mycobacterium and wileyonlinelibrary.com/jctb Nocardia were found that have not been reported to be involved in anaerobic digestion.…”