Resumo

Copper is one of the major exported metal and a fundamental raw material for the development and maintenance of several national industries. Mining is a polluting activity and the mine drainage is one of the greatest environmental impact of it. Mine drainage is characterized by a liquid rich in metals and acidic pH produced in the presence of microorganisms, sulphide minerals, water and oxygen. In the presence of certain ores like dolomite and chacolcite, the mine drainage can become neutral. Currently, some studies focus on understanding the biodiversity and distribution of microorganism communities in mine drainage, but few studies aim to assess the genomes present in copper mining environments and neither in neutral mine drainage. Therefore, we performed a chemical and metagenomics analysis, using Illumina sequencing, of two drainage samples (P4-2013 and P5-2013) from the mine of Sossego, Pará. The generated reads were quality filtered and it was not allowed ambiguous bases. Velvet and Metavelvet were used with different K-mers for the assembly step and the assembly quality was measured to choose the best assemblies. ORF calling was performed in prodigal, followed by blastp (NCBI non-redundant protein database) to identify genes. MEGAN was used to taxonomic annotation and functional annotation in SEED subsystems and KEEG pathways. STAMP and R were used for statistical analysis. The chemical analysis showed a large quantity of copper, iron and nickel. The taxonomic annotation showed the majority of sequences with bacterial origin. The predominant phyla for sample P4-2013 was Cyanobacteria and Deinococcus-Thermus while for P5-2013, Proteobacteria and Acidobacteria were responsible for more than 45% of the sequences. Functional annotation revealed genes related to copper homeostasis and tolerance, iron and nickel transport and zinc resistance and transport. This is the first neutral mine drainage metagenome and the results suggest a correlation between the presence of genes related to metal transport, tolerance and resistance mechanisms and the quantity of metals present in this environment.