Bioremediation potential of the consortium of indigenous microbial isolates in degrading multiwall carbon nanotube (MWCNT) present in contaminated water

Abstract

MWCNT is being explored in various sectors like medical healthcare, electronics, aerospace, defence research, and many more leading to the continuous generation of waste discharged into water sources. Once introduced into the environment it may adversely affect flora and fauna. It is high time MWCNT should be recovered, treated, and degraded from wastewater. Bio-degradation is one of the popular sustainable techniques for the remediation of hazardous contaminants. This work evaluated indigenous microbes Bacillus nitratireducens SW_NMI_TSB1, Comamonas denitrificans SW_NMI_TSB2, and Lysinibacillus fusiformis SW_NMI_TSB3 isolated from the nanomaterial manufacturing industry from India for their competence in degrading MWCNT. The microbes in this study showed survivability in the nutrient medium devoid of carbon but containing MWCNT (100 and 400 mg/L). The bacterial strain exhibited proliferation for up to 50 days. Degradation of MWCNT can be observed through TEM images which displayed the distorted morphology, XRD, and RAMAN spectroscopy revealed that treated MWCNT exhibit a loss of structural integrity. SEM images and colony forming unit (CFU) counts show a good survival rate of the three isolates independently and in the consortium. LCMS detected intermediates generated during MWCNT degradation. The microbes isolated in this study can survive in the presence of MWCNT and exhibit degradation of MWCNT. The three isolates could biodegrade the MWCNT however their consortium showed the highest potential. The prospects of this study lie in utilizing the consortium of these strains for large-scale MWCNT degradation, improving water treatment systems, and advancing sustainable nanomaterial management practices.

Graphical Abstract