• The Korean Journal of Ecology
• /
• v.22 no.1
• /
• pp.39-43
• /
• 1999

Serratia marcescens, an enterobacterium of gram-negative bacteria, is characterized by resistance of the admium. Cadmium sensitive PM strain did not grow in the medium at cadmium concentration of 50 ppm. PA strain was induced to accommodate to cadmium by cultivating the mother strain (PC strain) in the medium with 50 ppm cadmium. As compared with PC and PM strains, PA strain revealed the excellent growth in cadmium media and accumulated four to five times higher cadmium concentration in cell than other strains. PA strain accumulated 23% of cadmium in cells when cultured in medium treated with 100 ppm cadmium and this cadmium was more accumulated in cytosol fractions than membrane fractions. Analysis by TEM indicated that cadmium was concentrated as a form of granule in cytosol. In protein patterns of cell after the treatment of cadmium, two inducible proteins (28 KDa and 64 KDa) and one reducible protein (45 KDa) were detected by SDS-PAGE. By Atomic Absorption Spectrophotometer, the amounts of cadmium attached to inducible proteins of 28 KDa and 64 KDa were 318.28 ㎍ and 325.37 ㎍ per gram of protein, respectively. It is assumed that these inducible proteins play an important role in the mechanism of cadmium accumulation in cells. A plasmid of 23Kbp was found in S. marcescens. The ability of resistance to cadmium in plasmid was confirmed by curing experiments.

• Journal of Applied Biological Chemistry
• /
• v.60 no.2
• /
• pp.113-117
• /
• 2017

Bioremediation is a technique using microorganisms to clean up contaminated pollutants including heavy metals. It is well known that yeasts have a high capacity to remove a wide range of metals by biosorption. Therefore, this study was focused on to obtain yeast mutant that has strong tolerance to zinc (Zn), one of representative heavy metals. The Zn resistant yeast mutant (ZnR) was induced and isolated by growing yeast cells in media containing 1 mM $ZnCl_2$ and gradually increasing the concentration until 80 mM $ZnCl_2$, in which cells were adapted and survived. The induced ZnR cells showed strong tolerance to Zn stress compared with control cells. Moreover, the ZnR cells showed increased tolerance to cadmium and nickel stress but decreased tolerance to copper stress. The increased tolerance of ZnR cells to Zn stress was due to mutation of genes. This study can be useful in bioremediation of heavy metals as the metal tolerant microorganism was artificially induced in short time.