Unique Raoultella species isolated from petroleum contaminated soil degrades polystyrene and polyethylene

Polyolefin plastics, such as polyethylene (PE) and polystyrene (PS), are the most widely used synthetic plastics in our daily life. However, the chemical structure of polyolefin plastics is composed of carbon-carbon (C-C) bonds, which is extremely stable and makes polyolefin plastics recalcitrant to degradation. The growing accumulation of plastic waste has caused serious environmental pollution and has become a global environmental concern. In this study, we isolated a unique Raoultella sp. DY2415 strain from petroleum-contaminated soil that can degrade PE and PS film. After 60 d of incubation with strain DY2415, the weight of the UV-irradiated PE (UVPE) film and PS film decreased by 8% and 2%, respectively. Apparent microbial colonization and holes on the surface of the films were observed by scanning electron microscopy (SEM). Furthermore, the Fourier transform infrared spectrometer (FTIR) results showed that new oxygen-containing functional groups such as -OH and -C--O were introduced into the polyolefin molecular structure. Potential enzymes that may be involved in the biodegradation of polyolefin plastics were analyzed. These results demonstrate that Raoultella sp. DY2415 has the ability to degrade polyolefin plastics and provide a basis for further investigating the biodegradation mechanism.

Automated summary

Polyolefin plastics, widely used in our daily life, are difficult to degrade due to their stable carbon-carbon bonds. This study isolated a Raoultella sp. DY2415 strain from petroleum-contaminated soil, which can degrade polyethylene and polystyrene films. After 60 days, the weight of UV-irradiated polyethylene film and polystyrene film decreased by 8% and 2% respectively, and scanning electron microscopy revealed apparent microbial colonization and holes on the film surface. Fourier transform infrared spectrometer analysis showed the introduction of new oxygen-containing functional groups into the polyolefin structure. The study provides a basis for further investigation of the biodegradation mechanism.