SPION-accelerated biodegradation of low-density polyethylene by indigenous microbial consortium

Superparamagnetic iron oxide nanoparticles (SPION) with size ranging 10.6–37.8 nm were synthesized and characterized through XRD, FT-IR spectra, simultaneous TG-DTG-DTA, vibrational sample magnetometry (VSM) and transmission electron microscopy (TEM). Effect of SPION size variants on the growth-profile of Low-Density Polyethylene (LDPE) degrading microbial consortium consisting of Microbacterium sp., Pseudomonas putida and Bacterium Te68R was monitored in Minimal broth Davis medium lacking iron and dextrose. Besides accelerating the bacterial growth, these nanoparticles also improved the exponential phase durability by 36 h. Further, shifting in lag-phase and the additive effect of sonication was also documented on growth profiling. SPION of size 10.6 nm were selected and were found to significantly increase the biodegradation efficiency of consortium as revealed by λ-max shifts, Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA). The study highlights the significance of bacteria–nanoparticle interactions which can dramatically influence key metabolic processes like biodegradation.