Use of polyvinyl alcohol as a cell immobilization matrix for copper biosorption by yeast cells

Abstract

Although polyvinyl alcohol (PVA) gel has been used as a carrier for immobilized cells and enzymes, its use as an immobilization matrix for inactivated cells for biosorption studies has not been reported. In this study, we have demonstrated that the PVA matrix showed very favourable performance, vis-a-vis good physical and chemical properties, and a low mass transfer resistance. The PVA matrix showed negligible effect on the uptake capacity of the inactivated yeast used as the biosorbent. Biosorption equilibrium showed that the specific copper uptake of the biomass increased with an increase in the initial copper concentration, and decreased with an increase in biomass loading. The equilibrium was well described by Langmuir and Freundlich adsorption isotherms. Temperature over the range of 10-50°C had little effect on the biomass biosorption capacity, while pH showed significant effect. The PVA-yeast beads could be regenerated using 10 mmol dm-3 HCl, with up to 100% recovery, and the beads reused in five biosorption-desorption cycles with negligible decrease in the biosorption capacity. (C) 2000 Society of Chemical Industry.