Isolation, Characterization, and Identification of Plastic-degrading Bacteria from Bago City Landfill, Negros Occidental, Philippines


by: Pauline Anne M. Lamela, Yobhel Grace Diputado, Jay Marie Lumantas, Isabel Grace Gatpatan, Rhudith B. Cabulong


Plastic pollution is a ubiquitous contemporary problem that demands to be addressed with urgency. Microorganisms that can degrade plastics may hold the key to resolving this problem by providing genetic and metabolic pathway knowledge on plastic degradation. In this study, soil samples were taken from Bago City Sanitary Landfill in Negros Occidental to isolate bacteria capable of degrading plastic pollutants. For 60 days, 5 bacterial isolates were cultured in minimal medium with pieces of UV- and autoclave (AC)-sterilized PET films. After 60 days, the film reduction analysis showed that isolate PT1 significantly degraded 9.29% of the UV-treated PET films when compared with the control, uninoculated PET films. Through molecular and biochemical characterization, the isolate was identified as Rhodococcus gordoniae PT1. The other bacterial isolates that showed growth on minimal medium with plastic as the sole carbon source were identified as Acinetobacter wuhouensis, Acinetobacter bohemicus, and Streptomyces ruber. The scanning electron microscopy analysis revealed the presence of structural changes, such as cracks and holes, on the bacteriainoculated films, indicating plastic degradation. The ability of these bacteria to degrade plastic provides a foundation for bioremediation, green chemistry, and bioengineering, offering a potential solution for eradicating tough pollutants from the environment. However, the potential pathogenicity of certain isolates needs careful considerations before applying these bacteria for bioremediation and bioengineering. Finally, this is the first study to identify plastic-degrading bacteria in Bago City, Negros Occidental, and the first to describe the plasticdegrading potentials of the identified species.

Keywords: plastic-degrading bacteria, film-reduction assay, Bago City landfill, PET degradation, polyethylene glycol