• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.132-135
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• 1997

We prepared capsules containing Saccharomyces cerevisiae and Zoogloea ramigera cells for the removal of lead(II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. The S.cerevisiae cells grown in the capule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell expolymer density of encapsulated Z.ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell expolymer of Z.ramigera was 55mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulated S. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulated S. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.