Removal of heavy metals from metal-containing effluent by yeast biomass
The aim of this study was to investigate the biosorption of heavy metals, chrome (Cr) and tin (Sn) from metal-containing effluent by waste brewer’s yeast. Biosorption of Cr and Sn was studied under batch conditions at a pH value of 6.5. The biomass, non-viable cells of the yeast Saccharomyces cerevisiae, is able to adsorb tin from a tin effluent, containing trace amounts of other metals. The uptake proceeded quickly over the first 30 min and slowed down over the following 30 min. Research studies have described this phenomenon of fast initial sorption with a second slower phase. Also, a study has been conducted in this regard and states that initial removal is almost entirely dependent on biosorption of metal cations to the cell wall. The yeast can adsorb both chrome and tin from the respective effluents, but removal of tin is faster initially during the first 40 min. Removal of chrome after 60 min is higher than that of tin at the same time. This can likely be ascribed to the difficulty of removing tin from metalcontaining waste water. The yeast, S. cerevisiae, in a non-viable state, is able to adsorb chrome and tin from the chrome and tin effluents of a local iron and steel industry.
Key words: Saccharomyces cerevisiae, heavy metals, chrome (Cr), tin (Sn).