In this work, we compared the performance of a new method of cell immobilization in a novel matrix for biosorption. Yeast cells were entrapped in a polyvinyl alcohol (PVA) matrix, based on an adapted iterative freeze-thaw-freeze process. Spherical and uniform beads were produced, and SEM micrographs confirmed that the cells were uniformly dispersed within the PVA matrix. Further experiments revealed that the use of PVA as the immobilization matrix conferred better mechanical and chemical properties than the commonly used calcium alginate matrix. Experiments also showed that the PVA matrix gave rise to a lower mass transfer resistance than the alginate matrix. Finally, it was established that PVA-yeast biosorbent beads could be regenerated using dilute hydrochloric acid (10mM) and reused for at least five biosorption cycles with virtually no decrease in its bisorption capacity. Different metal/biosorbent in PVA-immobilized systems are currently being investigated.

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