Evaluation of polyester polyurethane-degrading capability of bacteria isolated from landfill sites

• Author Details:   
• Xuan Ngoc Thanh Nguyen
• Nguyen Nu Thao Lu
• Tham Van Hong Vo
• Hai Ngoc Nguyen

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Background: Polyurethane (PU) is one of the most widely used categories of plastics in modern life. The enormous demand for PU has contributed to the global plastic crisis. In recent years, microbial strains capable of degrading plastics have garnered significant scientific interest. In the study, bacterial strains were isolated from natural environment, such as soil and waste plastics, and screened for PU-degrading activity using Impranil as a model substrate.

Materials and Methods: The PU-degrading activity was evaluated on both liquid (Impranil) and solid (PU foam) substrates. Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) analyses were used to detect chemical and physical changes.

Results: FTIR spectra reveal that the urethane, and ester components, along with carbon chains in Impranil and PU foam, were degraded by the microorganisms. On the liquid substrate (Impranil), degradation was observed in urethane, and ester bonds. On the solid substrate (PU foam), it is likely that the urethane component was attacked by the bacterial strain. SEM images disclosed that fiber density of PU foam in inoculated nutrient broth (NB) ppeared to be lower compared to the control. The PU-degrading strains were identified as Bacillus velezensis.

Conclusion: These findings demonstrate that microorganisms from natural environment could play a significant role in addressing the global plastic pollution.