Biosorption of cadmium (Ⅱ) by Saccharomyces cerevisiae
XU Hui juan, LIAO Sheng yun, LONG Min nan, XU Jian bin (School of Life Sciences, Xiamen University, Xiamen 361005)
The characteristics of cadmium (Ⅱ) biosorption by free and immobilized Saccharomyces cerevisiae were studied . The dry cells of Saccharomyces cerevisiae showed strong ability to biosorb Cd 2+ that was affected by cell concentration , Cd 2+ concentration, pH value and immobilization method. It turned out that the highest percentage of Cd 2+ biosorbed by Saccharomyces cerevisiae was 93% in the case of test conditions; accordingly the biosorption capacity was 46.5 mg Cd 2+ /g dry cells. The dry cells treated with 1mol/L HCl after biosorption, 84% of uptaked Cd 2+ could be desorbed to the solution. On the other hand, the uptake of cadmium by immobilized cells was greatly influenced by sodium alginate concentration and CaCl 2 concentration while the cells were immobilized in alginate beads, and the Cd 2+ biosorption by cell free alginate beads could not be negligible.