Biosorption of manganese from groundwater by biomass of Saccharomyces cerevisiae

Heavy metal pollution has become one of the most serious environmental problems today. Biological methods such as biosorption or bioaccumulation strategies for the removal of metals ions may provide an attractive alternative to existing technologies. Microorganisms, as heavy metal bioadsorbents, offer a new alternative for removal of toxic or valuable metals in water. Saccharomyces cerevisiae has received increasing attention due to its unique nature and capacity for metal sorption. It is one of the most promising biosorbents capable of removing metal ions from aqueous solution. Manganese occurs naturally in many surface water and groundwater sources and in soils that may erode into this water. Eleven S. cerevisiae yeast strains in alive and dead forms were screened for biosorption and bioaccumulation of manganese from artificial aqueous solution. S. cerevisiae F-25 in alive form was found to be highly biosorbent for Mn+2 and biosorbed 22.5 mg Mn+2/gm yeast biomass. Optimization of environmental conditions reveals that optimum concentrations for maximum Mn2+ biosorption by S. cerevisiae F-25 in alive form were 4.8 mg Mn2+/l after 30 min at pH 7, agitation 150 rpm and yeast biomass concentration 0.1 gm/l at 30 °C. Competition of Mn+2 with other heavy metals shows that Mn+2 in control sample without, any other heavy metals added in solution at 4.8 mg/l of the biosorbed Mn+2 was 41.3 mg/g biomass. Addition of other heavy metals affects the percent of biosorbed Mn+2.