Studies Of Cr(Ⅲ) Biotransformation And Biosorption By Brewer's Yeast

Using brewer's yeast as the vector, the characteristics of Cr (III) biotransformation and biosorption were studied.The contents of chromium in different components from chromium-rich and normal yeast were determined. In chromium-rich yeast, the percentage of protein-binding forms in total centents was highest and reached to 33.1%, the contents of chromium combined with small molecules and the inorganic chromium accounted for 9.3%. The contents of DNA and RNA were 6.7% and 5.3% , respectively. In addition, the contents of polysaccharide and lipid were low.The yeast protein was separated for the study of biosorption of Cr (â…¢) .The combined effects of the initial pH, the concentration of Cr (â…¢) and the biosorption time were investigated. Using an orthogonal experimental design, the optimum biosorption conditions were deterimined.In condition of the initial pH 7.0, the Cr(â…¢) concentration 300mg/L, the biosorption time 2 h ,the biosorption quantity can reach to 34.86mg/g.The characteristics of protein in chromium-rich yeast were analyzed by UV and FTIR . The results indicated that carboxylate oxygen and chromium were bonding with coordinated bond, which changed the secondary protein structure.