Potential Bacteria Isolated from Contaminated Sites as Bio-degraders of Various Types of Plastic

Abstract

The growing demand for plastics and their improper disposal have resulted in a significant environmental pollution problem. While various management strategies have been employed to tackle this issue, the persistence of plastic pollutants in the environment is still a major concern. Therefore, exploring and developing sustainable and environmentally safe techniques, such as biodegradation using potential bacteria, can help mitigate plastic pollution and provide a viable solution. The purpose of this study was to isolate and identify potential bacteria for degrading plastics from six soil samples collected from five plastic-contaminated sites. The population of microorganisms in the soil ranged from 1.9 ×105 to 8.2 × 104 CFU/g. The screening of biodegradation abilities to degrade various types of plastics, including Polypropylene (PP), Polystyrene (PS), Polyethylene (PE), Polyethylene terephthalate (PET), and Polylactic acid (PLA) (Bioplastic), as measured by the diameters of the clear zones surrounding the colonies, revealed that out of 40 strains, only 8 strains could degrade various types of plastics. These bacteria were identified using 16S rRNA genes, which showed that NBI0106, NBI0108, NBI0109, and NBI0111 tend to be Streptomyces ardesiacus with similarity 99%, NBI0113 tend to be Pseudomonas plecoglossicida with similarity 99%, and NBI0305 tend to be Streptomyces cellulosae with similarity 100%. In addition, The Streptomyces ardesiaca strain NBI0111 demonstrated the highest degradation efficiency for PP plastic, with a clear zone diameter of 32.19  0.34 mm. This study shows the importance of identifying bacteria in plastic-contaminated soils and landfills, which may lead to the discovery of more effective bacteria strain with the capacity to degrade various types of plastic in real environmental conditions.