Carbonaceous nanomaterials are widely used in industry and consumer products, with growing concerns over their release into the environment and subsequent impacts on ecosystems and human health. Microbial transformation of carbonaceous nanomaterials may exert significant influence on their environmental fate and health effects; however, microbial transformation of these emerging contaminants is not fully understood. We recently observed the microbial transformation of multi-walled carbon nanotubes (MWCNTs) by a polycyclic aromatic hydrocarbon (PAH)-degrading bacterium, Mycobacterium vanbaalenii PYR-1. The purpose of this study was to clarify the underlying molecular mechanisms of the biotransformation processes. We utilized culture filtrate from M. vanbaalenii PYR-1 to react with carboxylic acid functionalized MWCNT. Multiple analytical methods, including UV-Vis spectroscopy, TEM and Raman spectroscopy, demonstrated in vitro degradation of MWCNT as shown by mass loss, structural changes, and shift in D-band to G-band intensity ratio. In addition, RT-qPCR analysis showed up-regulation of several genes encoding ring-hydroxylating oxygenases in M. vanbaalenii PYR-1 upon exposure to MWCNT. Our results will likely refine the current understanding of microbial transformation of MWCNT and provide clues to the underlying molecular mechanisms. Future research is needed to investigate MWCNT degradation by other environmental bacteria and microbial consortia, as well as its occurrence under various environmental conditions.

Molecular mechanisms underlying biotransformation of carbon nanotubes by Mycobacterium vanbaalenii PYR-1

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.