The rising levels of environmental pollutants necessitate innovative and efficient strategies for their mitigation. The environmental pollutant, included various organic pollutants as well as heavy metals, and industrial effluents, pose significant risks to human health and ecosystems, traditional methods for combating toxicants, like chemical treatments as well as physical removal processes have various limitations, and are generally inefficient with high concentration of contaminants. Microbial nanoparticles have emerged as a promising solution due to their eco-friendly synthesis and effective remediation capabilities. This chapter investigate the mechanisms by which these nanoparticles mitigate toxicants, including adsorption, catalytic degradation, biotransformation, and bioaccumulation. The applications of microbial nanoparticles in water treatment, soil remediation, air purification, and industrial effluent management are discussed, supported by relevant case studies. The complete overview underscores the latent of microbial nanoparticles that play a significant role in creating a cleaner and safer environment.