Biosorption and Bioaccumulation Abilities of Actinomycetes/Streptomycetes Isolated from Metal Contaminated Sites

Heavy metal pollution is of great concern. Due to expansion of industrial activities, a large amount of metal is released into the environment, disturbing its fragile balance. Conventional methods of remediation of heavy metal-polluted soil and water are expensive and inefficient. Therefore, new techniques are needed to provide environmentally friendly and highly selective remediation. Streptomycetes, with their unique growth characteristics, ability to form spores and mycelia, and relatively rapid colonization of substrates, act as suitable agents for bioremediation of metals and organic compounds in polluted soil and water. A variety of mechanisms could be involved in reduction of metals in the environment, e.g., sorption to exopolymers, precipitation, biosorption and bioaccumulation. Studies performed on biosorption and bioaccumulation potential of streptomycetes could be used as a basis for further development in this field. Streptomycetes are of interest because of their ability to survive in environments contaminated by metals through the production of a wide range of metal ion chelators, such as siderophores, which provide protection from the negative effects of heavy metals or specific uptake for specialized metabolic processes. Many strains also have the equally important characteristic of resistance to high concentrations of heavy metals.