Biosorption of metals by soil bacteria

Metal bioremediation is the process of using organisms like plants and animals to immobilize or extract metals from water or sediment. Bacteria metal interaction happens by formation of bio-oxides, reduction reaction, biomineralization and biosorption. Biosorption can be defined as the ability of biological materials to accumulate heavy metals from wastewater through metabolically mediated or physico-chemical pathways of uptake. Microorganisms involved in biosorption include Bacillus sp, Pseudomonas sps, zoogloea ramigera and Streptomyces sp. Rhodobacter sphaeroides, Alcaligenes eutrophus etc. The biosorption process involves a solid phase (sorbent or biosorbent; biological material) and a liquid phase (solvent; generally water) containing a dissolved species to be sorbed (sorbate metal ions). Due to higher affinity of the sorbent for the sorbate species, the later is attracted and removed by different mechanisms. The state of biomass, type of biomaterials, properties of metal solution chemistry, and ambient environmental conditions such as pH, influence the mechanism of metal biosorption. Preliminary testing of solid-liquid absorption system is based on two types of investigations namely equilibrium batch sorption tests and dynamic continuous flow sorption studies. The aim of this chapter is to outline the types of bacteria, which are involved in different factors that affect the mechanism, the role of functional group and the analytical tools used in biosorption. © 2011 by Nova Science Publishers, Inc. All rights reserved.