Research Trends in Bioleaching for the Recovery of Valuable Metals from Spent Lithium-Ion Batteries and Waste Printed Circuit Boards

Spent lithium-ion batteries (LIBs) and waste printed circuit boards (PCBs) pose significant environmental risks due to their toxic components, while also offering opportunities for resource recovery because of their valuable metal content.This review summarizes recent advances in bioleaching technologies for recovering metals such as Li, Co, Ni, Mn, and Cu from these waste materials.Various microorganisms, including Fe-and S-oxidizing bacteria and fungi, have been employed under different leaching conditions.Key operational factors, such as microorganisms, pulp density, pH, temperature, and bioleaching mode (direct, indirect, and two-step), are analyzed for their effects on metal recovery efficiency.Comparative insights into bioleaching strategies for LIBs and PCBs are presented.Although bioleaching offers an eco-friendly and cost-effective alternative to conventional pyrometallurgical and hydrometallurgical methods, challenges remain regarding its application at high pulp densities and on an industrial scale.Key words : bioleaching, spent lithium