Biodegradation of polyethylene by Zophobas atratus and its gut microorganisms

Abstract:

[Background] Waste plastic polyethylene (PE) is refractory due to its high chemical inertness, resulting in long-term pollution. [Objective] To investigate the effects of common plastic foam (PE) on the growth and development of Zophobas atratus and provide a theoretical basis for the application of Z. atratus as an insect in the degradation of PE plastic foam. [Methods] Z. atratus larvae were fed with four different diets: T1 (wheat bran), T2 (plastic foam), T3 (plastic foam+wheat bran), and T4 (no diet). After 30 days of feeding, the larvae were dissected and the gut contents were enriched in LB medium. The obtained culture was added to the medium with PE as the only carbon source for selective culture, from which the strains capable of degrading PE plastics were isolated. [Results] After feeding on plastic foam and wheat bran for 30 days, the Z. atratus larvae showed a survival rate of 76%. Fourier transform infrared (FTIR) spectroscopy detected significant changes in the peaks corresponding to the main functional groups of compounds in the feces, which indicated a break in the long chains of PE. Three strains causing significant erosion on the edges of PE films were isolated from the gut. [Conclusion] Z. atratus can feed on and digest PE plastics, and the gut microorganisms play a key role in the degradation of PE plastics. The findings of this study provide scientific evidence for the bioremediation of plastic pollution.