Bacterial Heavy Metal Resistance Genes and Bioremediation Potential

Abstract

There is a worldwide distribution of heavy metal pollution that can be managed with a bioremediation approach using microorganisms. Several bacterial species belonging to the Proteobacteria have been shown to tolerate heavy metal stress, including toxic salts of noblemetals. Rhodobacter sphaeroides, a model bacterium has previously been utilized for bioremediation studies. A bioinformatics approach was employed here to identify the distribution of genes associated with heavy metal tolerance among the sequenced bacterial genomes currently available on the NCBI database. The distribution of these genes among different groups of bacteria and the Cluster of Orthologous Groups (COGs) were further characterized. A total of 170,000 heavy metal related genes were identified across all bacterial species, with a majority of the genes found in Proteobacteria (46%) and Terrabacteria (39%). Analysis of COGs revealed that the majority of heavy metal related genes belong to metabolism (COG 3), including ionic transport, amino acid biosynthesis, and energy production.