MICROBIAL BIODIVERSITY ANALYSIS OF HEAVY METAL CONTAMINATED SOIL: A METAGENOMICS-BASED APPROACH

Abstract

The current study focused on the exploration of bacterial community in heavy metal contaminated soil using culture dependent and independent approaches that might be applied to the bioremediation process. A total of 150 bacterial colonies were examined from the heavy metal-contaminated soil at initial level, and 25 isolates were chosen for further examination. Finally, twelve strains were chosen for future research based on their high levels of heavy metal resistance. The 10 bacterial strains i.e.,1K-10K were then characterized on the basis of their morphology and microscopic analysis. The morphological and biochemical characteristic relied on the basis of Bergey’s manual of bacterial classification that 1K as Pseudomonas sp., 2K as Enterobacter sp., 3K as Streptococcus sp., 4K as Staphylococcus sp.,5K as Staphylococcus sp., 6K as Pseudomonas sp., 7K as Micrococcus sp., 8K as Staphylococcus sp., 9K as Staphylococcus sp. & 10K as Staphylococcus sp. In metagenomics analysis, the most prevalent bacteria present in samples were “Actinobacteria, Proteobacteria, Acidobacteria, Pseudomonas Cyanobacteria, Bacteriodes, and Sphingomonas. Among the 29 identified phyla, Chloroflexi and Tenericutes were the most dominant phyla and their relative abundance ranged from 0.75-1.00. While, on the genera level, the most abundant genera were Blautia, Rhodoplanes followed by Prevotella and Arenimonas. The relative abundance of these genera ranged from 0.75% to 1.00%. Depending on the relative abundance of taxons, the results of this study showed Proteobacteria, Synergistetes and Bacteriodes were most abundant phylum while the least abundant phylum present in heavy metal contaminated soil was Chlamydia and Tenericutes. Screening of soil-based libraries using functional and sequence-based specifications, which has disclosed information on soil microbial communities, has made it possible to identify new microbial communities. Thus, the culture dependent and independent approaches revealed that even heavy metal contaminated soil compose of diverse group of bacterial community that could be explored for bioremediation purposes.