In Vitro Removal of Cd and Pb Through the Bacterial Strain Burkholderia zhejiangensis CEIB S4-3: Efficiency and Cellular Mechanisms Implicated in the Process
2025
Alondra Abigail Hernández-Guerrero | María Luisa Castrejón-Godínez | Patricia Mussali-Galante | Efraín Tovar-Sánchez | Alexis Rodríguez
Heavy metals are among the most toxic environmental pollutants. They are a group of chemical elements broadly distributed in different environments. Anthropogenic activities such as agriculture, livestock farming, and mining release large amounts of waste that contain toxic heavy metals into the environment. Bacteria are organisms that present a wide diversity of cellular mechanisms that can be used to develop efficient, low-cost, easy-to-implement, and sustainable processes to remediate sites contaminated with heavy metals. In this study, the capacity of the strain Burkholderia zhejiangensis CEIB S4-3 to remove Cd, Pb, and the mixture of both metals was evaluated through in vitro experiments. B. zhejiangensis CEIB S4-3 can eliminate on average 90% of Cd+2 and 91% of Pb+2 present in the study system (50 mg/L), while in the presence of the mixture of both heavy metals, the bacterial strain, the removal of Cd and Pb was 59 and 75%, respectively. The main cellular mechanism for removing Cd was extracellular biosorption, while, in the case of Pb, it was intracellular bioaccumulation. Heavy metals from the mixture of Cd and Pb were removed through extracellular absorption. In addition, the analysis of the genome of the bacterial strain revealed the presence of genes related to resistance to heavy metals, such as genes implicated in sensing and transcriptional response to heavy metals exposure and heavy metals efflux systems as the most important. The data obtained in this work can be the basis for developing new systems to remove Cd and Pb using B. zhejiangensis CEIB S4-3.
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