Implications of SPION and NBT Nanoparticles upon In Vitro and In Situ Biodegradation of LDPE Film

The comparative influence of two nanoparticles [viz., superparamagnetic iron oxide nanoparticles (SPION) and nanobarium titanate (NBT)] upon the in vitro and in situ low-density polyethylene (LDPE) biodegradation efficiency of a potential polymer-degrading microbial consortium was studied. Supplementation of 0.01% concentration (w/v) of the nanoparticles in minimal broth significantly increased the bacterial growth, along with early onset of the exponential phase. Under in vitro conditions, ${\lambda}$-max shifts were quicker with nanoparticles and Fourier transform infrared spectroscopy (FTIR) illustrated significant changes in CH/$CH_2$ vibrations, along with introduction of hydroxyl residues in the polymer backbone. Moreover, simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) reported multiple-step decomposition of LDPE degraded in the presence of nanoparticles. These findings were supported by scanning electron micrographs (SEM), which revealed greater dissolution of the film surface in the presence of nanoparticles. Furthermore, progressive degradation of the film was greatly enhanced when it was incubated under soil conditions for 3 months with the nanoparticles. The study highlights the significance of bacteria-nanoparticle interactions, which can dramatically influence key metabolic processes like biodegradation. The authors also propose the exploration of nanoparticles to influence various other microbial processes for commercial viabilities.