ABSTRACT
Based on the physiology of microorganisms, mechanisms involved in the uptake of metal pollutants have been identified as passive and active. The passive mechanism is also known as metabolism-independent mechanism because it does not require consumption of energy to take place. The metal adsorption capacity and mechanism of microorganisms can be affected in the presence of relatively high concentration of metals in the solution. This can result into the inhibition of the microorganisms which develop a strategy to respond to the change in the surrounding and maintain low intracellular concentration of metals. Sensing of the danger may trigger physiological changes in the microorganisms as they prepare to develop mechanisms that will allow them to resist the threat caused by the metals against their survival. Detoxification of metal by microorganisms could also occur through the use of intracellular metal resistance mechanisms that involve metal binding or sequestration by metalloproteins such as metallothioneins and phytochelatins.
