Polyethylene Biodegradation Potentials of Pseudomonas aeruginosa and Micrococcus sp. Isolated from Waste Dumps and Farmlands in Nsukka, Enugu State, Nigeria

Abstract

Background: Low Density Polyethylene (LDPE) are plastic materials extensively used in packaging, constituting recalcitrant environmental pollutants that defy natural degradation processes. Aim: This study isolated bacteria from a Nigerian environment and assessed their potential for LDPE biodegradation. Methods: Using standard procedures, Bacteria were isolated from polythene samples collected from farmlands and waste dump sites in Nsukka metropolis. Mineral salt medium (MSM) was prepared, with LPDE as sole carbon source, and used for isolation. Optical density (OD600 nm) was used to study bacterial growth on LDPE as sole carbon source as proof of biodegradation. Both organisms demonstrated steady growth on LDPE over time. Results: Pseudomonas aeruginosa and Micrococcus sp. were identified based on morphological and biochemical characteristics. Ability to grow on LDPE as a sole carbon source was studied as evidence of polyethylene biodegradation. Organisms were inoculated into MSM and incubated at 37°C and 50°C for 15 days. Maximum growth was recorded after 15 days of incubation for both organisms. P. aeruginosa and Micrococcus sp. showed steady growth at 37°C as well as 50 ⁰C. Micrococcus sp. recorded highest growth; 0.324 nm and 0.312 nm at 37°C and 50°C respectively, after 15 days. Similarly, P. aeruginosa recorded highest growth of 0.40 nm and 0.258 nm for 37°C and 50°C respectively. LDPE degradation increased with increase in time. Conclusion: This study demonstrates the enormous polyethylene-degrading potentials of P. aeruginosa and Micrococcus sp. isolated from Nsukka, Nigeria.