Metal(loid)-Contaminated Soils as a Source of Culturable Heterotrophic Aerobic Bacteria for Remediation Applications

<p>Heavy metal–contaminated soils are a serious environmental problem. Herein, the culturable heterotrophic bacterial community present on two metal(loid)-contaminated sites in the Northern Portugal was investigated. The bacterial counts ranged from 5.96 to 7.69 and 7.04 to 7.51 (log CFU g⁻¹ soil) in Sites 1 and 3, respectively. The bacterial population was predominantly composed of <i>Firmicutes, Proteobacteria</i>, and <i>Actinobacteria</i> on both sites. The most represented genera in Site 1 were <i>Bacillus</i> (41%) and <i>Pseudomonas</i> (27%), whereas <i>Arthrobacter</i> (21%) and <i>Pseudomonas</i> (13%) were the most represented genera in Site 3. Several bacterial isolates showed tolerance to high concentrations of metal(loid)s, suggesting that both contaminated sites are a valuable source of metal(loid)-tolerant bacteria, which may be further used in bioremediation and/or phytoremediation processes.