Uptake and distribution of cadmium by strain Pseudomonas aeruginosa san ai

Abstract

The bioremediation of heavy metals using microorganisms has received a great deal of attention for its potential application in industry. Among the most common heavy metals used and the more widespread contaminants of the environment is mercury, cadmium, lead and copper. The mechanisms associated with metal removal by microorganisms are complex and occur as: biosorption of metal ions on the cell surface, intracellular uptake of metal ions or chemical transformation of metal ions by microorganisms. Biosorption is a passive uptake of metals based upon physicochemical interactions between metal and functional groups of the cell wall. Intracellular metal uptake, sometimes called active biosorption is slow and nutrient dependent process. This way of uptake is accumulation of metal cations by living cells, where they were modified and used for microbial needs or in form that is less/no toxic, and returned in environment. Various microbial species, mainly Pseudomonas, have been shown to be efficient in removal of the different heavy metals from polluted effluents, using combinations of mentioned mechanisms. This study represents trial to characterize and determine Cd2+ uptake by strain P. aeruginosa san ai. In order to evaluate tolerance of the strain, MIC for cadmium were determined, afterwards the metal uptake was monitored. Preliminary results showed that MIC for Cd was 2 mM. More than 80% of cadmium added to the culture, grown in submerged conditions, was found to be associated with biomass. Investigation of distribution or metal in cell fractions, as well in protein, lipid and polysaccharide fractions is underway.