Analysis of Bacterial Community Structure and Diversity in Traditional Gold Mining Waste Disposal Site by Using a Metabarcoding Approach

Abstract

The purpose of this study was to evaluate the effect of mercury contamination on bacterial community and structure in the contaminated soil at the mining waste disposal site (sample1) compare with uncontaminated soil (sample2). Mercury level was analyzed using the CVAFS method, and analysis of bacterial composition was carried out using metagenomic data generated from the V3-V4 region of 16S rRNA obtained from paired-end Illumina MiSeq reads. The results showed that the mercury level in sample 1 and 2 were 230 and 1.5 mg/kg, respectively. Metagenomic analysis showed that there were 57,031 reads in sample 1, consisting of 16 phyla, and 53,525 reads in sample 2, consisting of 15 phyla. Firmicutes was the most abundant phylum in sample 1, followed by Proteobacteria , Planctomycetes, Acidobacteria, Actinobacteria , and Chlorophlexi . Sample 2 was dominated by Firmicutes, followed by Proteobacteria and Planctomycetes . Bacilli was the most abundant class in sample 1, followed by Gammaproteobacteria and Planctomycetia . Bacilli was also the most abundant class in sample 2, followed by Clostridia. The predominating families in both samples were Bacillaceae. Aeromonadaceae was a large family after Bacillaceae in sample 1, and Peptostreptococcaceae in sample 2. This study provides an understanding of the microbial community structure in an area that is highly contaminated with mercury to open insight into the potential of these bacteria for mercury bioremediation.