Abstract
Heavy metal pollution represents a serious threat to environmental sustainability and human health, with lead (Pb) identified as one of the most hazardous due to its non-biodegradable nature and tendency to bioaccumulate. This study evaluated the biosorption capacity of Saccharomyces cerevisiae yeast and two strains of lactic acid bacteria (Lactobacillus acidophilus and Lactobacillus plantarum) for the removal of lead ions from aqueous solutions under varying experimental conditions. The effects of pH, contact time, temperature, initial metal concentration, and biosorbent dose were systematically investigated. Optimal lead removal by S. cerevisiae occurred at pH 6, 28 °C, 5 mg/L initial lead concentration, 1 g/L biosorbent dose, and a contact time of 60 minutes, achieving a removal efficiency of 72.4%. Comparative analysis showed S. cerevisiae to have a higher removal efficiency than both LAB strains. Adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the primary mechanism. Morphological and elemental analysis using SEM and EDX confirmed lead binding on the yeast surface. These findings illustrate the potential of microbial biosorbents, particularly S. cerevisiae, as cost-effective and efficient agents for lead remediation in contaminated water systems.