Bioremediation of Heavy Metal Using Burkholderia cenocepacia and Optimization of Heavy Metal Remediation

Abstract

Rapid industrialization has resulted in widespread metal contamination of ecosystems, creating a need for effective biological remediation strategies. This study investigated the metal tolerance and biosorption characteristics of Burkholderia cenocepacia isolated from heavy metal-contaminated soil. The strain demonstrated effective removal of different metal ions, including As³⁺, Pb²⁺, Zn²⁺, and Cr⁶⁺, from multi-metal solutions. Minimum inhibitory concentration (MIC) assays revealed variations in metal tolerance, indicating strain-specific responses to metal stress. The strain showed strong metal tolerance capacity; however, the simultaneous presence of multiple metal ions resulted in competitive binding and reduced metal removal, suggesting inhibition of metal adsorption onto extracellular polymeric substances (EPS). FTIR analysis confirmed the involvement of bacterial functional groups in metal binding and revealed the appearance of new peaks following metal exposure, indicating possible EPS production and associated changes in cellular surface chemistry. EDX analysis further demonstrated metal deposition on bacterial surfaces and within cytoplasmic regions, together with morphological changes and distinct metal adsorption patterns. XRD and EDX analyses confirmed intracellular metal accumulation, highlighting the complexity of microbial–metal interactions. Differences in metal distribution patterns suggested species-specific accumulation mechanisms influenced by metal availability and environmental conditions. The findings emphasize the importance of selecting suitable bacterial strains for specific metal containing effluents, particularly where competitive interactions may limit simultaneous metal uptake. The broad metal tolerance and removal capacity of B. cenocepacia indicate its potential application in heavy metal remediation through bioreactors or in situ treatment systems.