INFLUENCE OF ELEVATED TEMPERATURES ON THE MICROBIOME OF A MUNICIPAL SOLID WASTE LANDFILL

Landfill microbial diversity is poorly understood: it is controlled by both primary environmental drivers (redox geochemistry, moisture, temperature) as well as localized factors (i.e., interbedded soils, unique waste inputs including incinerator ash and Al processing “dross” which can promote inorganic exothermic reactions). In particular, the microbiology of normal (25-45 C) and elevated temperature landfill settings (up to 100 C) has not been broadly investigated using modern sequencing techniques. Focusing on waste samples from three boreholes in a Florida landfill attaining elevated temperatures at depth [temperature range 27–87 °C], we compared and contrasted 16s rRNA amplicon sequences using an Illumina Miniseq to generate a library of paired end reads. Amplicon data were then analyzed to determine microbial community profiles. Most samples were dominated by spore-forming bacteria (Firmicutes); however, samples collected at temperatures greater than 80 °C also had significant fractions of Proteobacteria, Actinobacteria or mixed assemblages of low abundance Phyla. Samples below 63 °C included notable Thermotogota and Proteobacteria. Transition temperature samples exhibited great variability including Euryarchaeota. The diversity represented in the high temperature amplicon data introduce us to a largely unexplored community which differs greatly from adjacent mesophilic communities.