Developments in Bioremediation of Soils and Sediments Polluted with Metals and Radionuclides – 1. Microbial Processes and Mechanisms Affecting Bioremediation of Metal Contamination and Influencing Metal Toxicity and Transport

Review on iron availability in soil: interaction of Fe minerals, plants, and microbes

“…1 and 2). Iron complexing organic compounds are considered the main part of soluble Tabak et al 2005) Fe III species in soil and are of real relevance particularly in an agricultural context (Hinsinger 1998;van Hees and Lundstrom 2000;Hinsinger 2001). This aspect is even more important when calcareous soils are considered; in fact, the pH values of calcareous soils are so unfavorable to the solubility of Fe ions that these induce very often the onset of severe Fedeficient symptoms in cultivated plants (Loeppert et al 1984;Marschner and Römheld 1994;de Santiago and Delgado 2006).…”

Developments in Bioremediation of Soils and Sediments Polluted with Metals and Radionuclides. 3. Influence of Chemical Speciation and Bioavailability on Contaminants Immobilization/Mobilization Bio-processes

“…Microorganisms have a high surface area-to-volume ratio because of their small size and therefore provide a large contact area that can interact with metals in the surrounding environment. Microbe-metal interactions have received much attention in the last years due to the potential use of microorganisms for cleaning metal-polluted environments (Gadd 1993(Gadd , 1996(Gadd , 1999(Gadd , 2000(Gadd , 2002Gadd & White 1993;White et al 1997Lloyd & Lovley 2001;McLean et al 2002;Tabak et al 2005). The ability of microorganisms to affect metal speciation relates to their ability to effect and/or mediate mobilization or immobilization processes that influence the balance of metal species between soluble and insoluble phases (Wiatrowski & Barkay 2005).…”

“…Redox reactions can mobilize or immobilize metals depending on the metal species involved. As well as being an integral component of biogeochemical cycles for metals, these processes may be exploited in bioremediation of soils and sediments polluted by metals and radionuclides (Gadd 1993(Gadd , 1996(Gadd , 1999(Gadd , 2000(Gadd , 2002(Gadd , 2004Gadd & White 1993;White et al 1997Lloyd & Lovley 2001;McLean et al 2002;Tabak et al 2005). Almost all metal-microbe interactions have been examined as a means for removal, recovery or detoxification of inorganic and organic metal or radionuclide pollutants (Lovley & Coates 1997;Stephen & MacNaughton 1999;Eccles 1999).…”

Microbes as Potential Tool for Remediation of Heavy Metals: A Review

“…The only known bacterial metallothionein locus, designated smt, that has been cloned and structurally characterized in Synechococcus strain PCC 6301 and in Synechococcus strain PCC 7942 [72,73]. The smt locus contains of two divergently transcribed genes, smtA and smtB which mediate resistance to zinc and cadmium in Synechococcus strains [74,75].…”