Biodegradability of polyethylene by efficient bacteria from the guts of plastic-eating waxworms and investigation of its degradation mechanism

Polyethylene (PE) has been regarded as non-biodegradable for decades, and the evidence for its degradation by bacteria remains unclear in the literature. Waxworms have recently gained attention for their ability to degrade natural long-chain polymers and synthetic plastic. This study aims to explore the potential of low-density polyethylene (LDPE)-degrading bacteria from the gut symbionts of lesser waxworm (Achroia grisella) larvae for the effective biodegradation of LEDP. Two bacterial isolates (LDPE-DB1 and LDPE-DB2) exhibited the greatest reduction in tensile strength among all isolates (P < 0.0001), reaching 51.3% and 58.3%, respectively. The bacterial strains LDPE-DB1 and LDPE-DB2 stand for molecularly identified species, Citrobacter freundii and Bacillus sp., respectively. After 5 days of incubation, the cell density of LDPE-DB1 and LDPE-DB2 reached 2.20 x 10(8) and 1.8 x 10(8) CFU/mL, respectively. However, after 30 days of incubation, the cell density reached 7.3 x 10(8) and 5.9 x 10(8), respectively. The formed cavities indicate the high activity of the isolated bacteria from Achroia grisella larvae where the cavities reach a depth of up to 1.2 mu m. The findings of this study demonstrated the presence of LDPE-degrading bacteria in Achroia grisella and provide promising evidence for the biodegradation of plastic waste management in the environment.

Automated summary

This study investigated the potential of gut symbionts of lesser waxworm larvae to degrade low-density polyethylene (LDPE). Two bacterial isolates, identified as Citrobacter freundii and Bacillus sp., showed the highest reduction in LDPE's tensile strength. The cell density of these bacteria increased over time, indicating their high activity in degrading LDPE. These findings provide promising evidence for the biodegradation of plastic waste management in the environment.