Int. J. Adv. Res. Biol. Sci. (2023). 10(7): 93-102 93 International Journal of Advanced Research in Biological Sciences ISSN: 2348-8069 www.ijarbs.com (A Peer Reviewed, Referred, Indexed and Open Access Journal) DOI: 10.22192/ijarbs Coden: IJARQG (USA) Volume 10, Issue 7 -2023 Research Article A Comparative Study of Biodegradation of Virgin and Weathered Low-density Polyethylene by Proteus and Lactobacillus spp. Uwakwe Felicia E. 1 , Ezejiofor Tobias I.N. 2 , Ogbulie Toochukwu, E. 2 & Anyalogbu Ernest A.A. 3 1 Department of Environmental Health Science, Federal University of Technology, Owerri. 2 Department of Biotechnology, Federal University of Technology, Owerri. Corresponding author: fellyuwakwe@gmail.com Abstract The environmental and public health burdens arising from plastic wastes, and the need to develop an eco-friendly strategy to manage the wastes prompted this research work. In this study, the role of microorganisms in virgin and weathered low-density polyethylene degradation was investigated. Two (2) bacterial species, Lactobacillus and Proteus were isolated from a waste dumpsite in Avu, Owerri West LGA, Imo State, Nigeria. Incubation of the polyethylene sachets with the test isolates was for 60 days, and their ability to degrade polyethylene was evaluated by microbial growth measurement (OD 600 ), changes in the functional groups of the polyethylene (FTIR) and weight loss analysis. Results revealed the presence of gas bubbles and turbidity of the microbial inoculated culture media. Optical density measurement showed progressive and gradual increase in absorbance, with Lactobacillus sp. recording higher concentrations in both virgin (0.115 – 0.550) and weathered (0.116 – 0.790) polyethylene cultures than Proteus sp. (0.122 – 0.451) and (0.114 – 0.710). Fourier transform infrared spectroscopy (FTIR) revealed the presence of additional carbonyl, hydroxyl and methylene functional groups in the polyethylene sachets treated with the test isolates (Lactobacillus sp: virgin PE – 10 peaks, weathered PE – 13 peaks; Proteus sp: virgin PE- 7 peaks, weathered PE – 10 peaks) as against the control (virgin PE – 8 peaks and weathered – 7 peaks). Similarly, weight loss analyses also revealed higher percentage weight loss in weathered PE than virgin PE, with Lactobacillus sp also recording greater percentages (44% and 32%) than Proteus sp (28% and 22%). These observations were indications of microbial metabolic activities, and the degradation and utilization of the polyethylene by the test organisms as sole source of carbon and energy. It was concluded that Lactobacillus sp. and Proteus sp. have the ability to degrade polyethylene, with Lactobacillus sp. displaying a higher capability, and that weathered polyethylene is more susceptible to microbial attack than virgin. Keywords: polyethylene, Lactobacillus sp., Proteus sp. biodegradation, microbial isolates DOI: http://dx.doi.org/10.22192/ijarbs.2023.10.07.011