Certain living organisms have the ability to adbsorb metals, and plants can also adbsorb metals. We focus on microorganisms, and use the protein and polysaccharide on the surface of microorganisms to attract metal ions. The advantages of microorganisms are that they are environmentally friendly and the preparation procedure is easy. Microorganisms, which can be adbsorbent, are propagated just by cultivation with nutrient. Accordingly, they have a considerable advantage in terms of production cost.
However, since the negative charges of microorganisms and positive charges of metal ions attract each other, it is difficult to adsorb specific metals selectively. Moreover, desorption process of metals adsorbed by microorganisms is usually complicated. To resolve these problems, we focus on metal-biding peptides and cell surface display technology, and are working on the development of technology to selectively adsorb metals using the surface of microorganisms.