Comparative biosorption of Pb²⁺ by live and inactivated Wickerhamomyces anomalus QF-1-1: Mechanisms and...

Lead (Pb²⁺) is a priority heavy metal pollutant of global concern. The World Health Organisation (WHO) sets a limit of 0.01 mg/L for lead in drinking water, whilst Chinese national standards stipulate that industrial wastewater discharges must not exceed 1 mg/L. This study investigated the anomalous W. anomalus QF-1-1 using batch adsorption experiments, FT-IR, and SEM techniques to examine the adsorption characteristics and mechanisms of live and inactivated cells towards Pb²⁺. The optimal adsorption conditions were pH = 6, a dosage of 11 g/L, and adsorption at 30 °C for 24 h. The maximum adsorption capacities for live and inactivated cells were 20.89 mg/g and 19.16 mg/g, respectively. The adsorption process conformed to pseudo-second-order kinetics and the Freundlich isotherm, indicating spontaneous, exothermic chemical adsorption. FT-IR and SEM analyses confirmed that functional groups, including hydroxyl and carbonyl groups, as well as the cell wall, are involved in the adsorption process. The mechanism involves surface complexation, electrostatic interactions, and extracellular precipitation. This bacterial strain is safe, low-cost, and renewable, and can provide technical support for the remediation of Pb²⁺ contamination and food safety.