Unveiling the potential of microbial biominers in bioleaching for heavy metal recovery from E-waste – A comprehensive review

Modern-day technology is rapidly developing giving rise to increased production of electronic devices. Electronic waste or e-waste generation is a serious environmental concern as e-waste encompasses around 70 % of the total toxic waste produced in the world. The fundamental components of e-waste contain a complex array of heavy metals in large quantities, some of which are toxic to the environment but are vital resources. As a result, e-waste recycling is critical not only for waste treatment, but also for metal recovery and economic growth. Physical and chemical strategies for recovering heavy metals from e-waste were partially successful as the resulting by-products were still toxic to the environment. The limitations of these conventional methods gave rise to biological strategies like bioleaching that are environmentally-friendly as they employ biological agents such as bacteria. While most reviews only highlight about bioleaching process and its mechanisms, very few provide information about the sequestration mechanisms followed after bioleaching along with it. This review provides valuable insights on the bioleaching process along with the sequestration mechanisms by microbes after bioleaching and a hypothetical analysis of bioleaching by bacteria, fungi and algae as a consortium for a self-sustaining and effective way of heavy metal recovery from e-waste.