A novel FTIR-ATR spectroscopy based technique for the estimation of low-density polyethylene biodegradation

Microorganisms have been shown to have an adaptive ability for efficiently breaking down oxidized polymers. In the present study, we have developed a rapid and sensitive analytical technique using Fourier Transform Infrared coupled Attenuated Total Reflectance (FTIR-ATR) spectroscopy to quantify low density polyethylene (LDPE) biodegradation by microorganisms. In order to demonstrate the utility of this technique, LDPE biodegradation was performed using two bacterial strains, Microbacterium paraoxydans and Pseudomonas aeruginosa. Prior to quantification, these bacterial strains were acclimatized to nitric acid pretreated LDPE for 2 months. The acclimatized strains were then subjected to in vitro biodegradation assay with the pretreated LDPE as its sole carbon source for another 2 months. Subsequently, biodegradation quantification was performed with FTIR-ATR spectroscopy using various concentrations of LDPE standards for comparison. It was observed that the percentage of transmittance at 2920 cm−1 was directly proportional to the concentration of LDPE. Results indicated that M. paraoxydans degraded 61.0% of LDPE while P. aeruginosa degraded 50.5% in 2 months. In conclusion, we established a rapid and sensitive FTIR-ATR spectroscopy based technique to quantify LDPE biodegradation.