DNA metabarcoding of the leachate microbiota from sanitary landfill: potential for bioremediation process

Leachate generation contains a variety of toxic compounds, and is a major problem for municipal solid waste (MSW). Microbial profile knowledge is essential to new alternatives and improvements in current treatments of these effluents. In this respect, the microbial community in the leachate from the sanitary landfill of the city of Foz do Iguaçu was analyzed. The 16S rDNA metabarcoding suggested the dominance of fermenting bacteria belonging to Firmicutes phylum, followed by Proteobacteria, Bacteroidetes, and Synergistetes. The most abundant genera were Sedimentibacter, Vulcanibacillus, and Anaerovorax. However, 60% of amplicon sequence variants (ASVs) were not classified taxonomically. In addition, an expressive abundance was attributed to the superphylum known as PVC group, little studied and with unknown scientific potential. The leachate acidogenic phase was masked in the chemical and physical analyzes. Nevertheless, it was evidenced in the metabarcoding methodology. No specifically methanogenic group was detected in significant abundance. Therefore, from bacterial community identification, a bioremediation process can be designed. Enriched culture media can be developed and targeted to the recovery of specific groups which may be involved in leachate biodegradation. What is more, the results expand the knowledge of bacterial diversity, especially from the presence of unknown genera in this habitat.