Biosorption Of Heavy Metal Ions (cd²⁺ And Zn²⁺) By Sacchaoromyces Cerevisiae And Bacillus Mucilaginous

Two strains, Saccharomyces cerevisiae and Bacillus mucilaginosus, are investigated in their abilities to endure heavy metal ions in this study. Meanwhile, the biosorption capacities of Cd2+ and Zn2+ by Saccharomyces cerevisiae and Bacillus mucilaginosus have been researched through altering the cultivating and biosorption conditions. Besides, the two microorganisms have been adapted in Cd2+and Zn2+mediums as to improve their biosorption capa(:ities.'fhe result indicates that the highest tolerant concentrations of Saccharomyces cerevisiae to Cd2 and Zn2+ are 50-60mg·L-1 and 300mg·L-1 or so respectively; While the highest tolerant concentrations of Bacillus mucilaginosus to Cd2 and Zn2+ are about 100mg·L-1 and 100-110mg-L"1 respectively.The biosorption capacities of the two microorganisms have been tested by changing adsorption time, initial pH, cell dosage and the initial Cd2 and Zn2+ concentrations. The result indicates that under the adsorption conditions of Cd2+ and Zn2+ 5mmol·L-1,14.98g dry cell·L-1 and 19.97gdry cell·L-1, the adsorption rates of Cd2 and Zn2+ by Saccharomyces cerevisiae are 93.15% and 84.00% respectively; While under the adsorption conditions of Cd2+ and Zn2+ 5mmol·L-1,40.0g dry cell·L-1 and 29.8g dry cell·L-1, the adsorption rates of Cd2 and Zn2+by Bacillus mucilaginosus are 87.45% and 97.50% respectively.After seven and nine generations'metal ion adaptations to Saccharomyces cerevisiae, the tolerance to Cd2+ and Zn2+.can be obviously improved and its biosorption capacity of Cd2+ can be improved as well; While After eight and nine generations'metal ion adaptations to Bacillus mucilaginosus, its biosorption capacity of Cd2+and Zn2+can both be improved.