A comprehensive review on sustainable removal of micropollutants in wastewater by micro-biotechnological approaches with special reference to microbial associated nanoparticles

Micropollutants (MPs) are the burgeoning contaminants which are released in wastewater (WW) due to the anthropogenic activities. Though MPs are detected in low amount in WW but are highly toxic and non-degradable; are accountable for global water quality and health hazards. The conventional WW treatment is energy inefficient and also results in hazardous sludge; hence alternative sustainable approaches are the ‘need of hour’. Recent micro-biotechnological methods based on bio-adsorption, membrane filtration, biocatalysts, bioreactors, and nanotechnology are effective in removal of MPs. Bacteria, fungi, and microalgae can degrade these MPs through the mechanisms of biosorption, biotransformation, bioaccumulation, and bioconversion, even at high concentrations. The nanotechnological tools using microorganisms are synthesized as microbial based nanoparticles (MNPs) employing potential strains of bacteria, fungi, and microalgae, can be possibly integrated into existing membrane or adsorption technological methods. MNPs have revealed as a potential for elimination of MPs from WW, the systematic studies are still in infancy. However, the aspects related to their recovery, regeneration and efficacy must be justified to confirm their application as future workhorses in the real WW treatment plants. This comprehensive review aims to provide information on MNPs as sustainable and cost-effective tools for bioremediation of MPs in WW.