Comparison of three insect larvae biodegrading polyethylene and role of the intestinal bacterial strains in polyethylene degradation by Galleria mellonella larvae

<title>Abstract</title> Polyethylene (PE) has been described as the most abundant plastic worldwide, such as mulching films and plastic bags. A few insects have been identified to ingest and metabolize polyethylene. In this study, we contrasted the degradation ability of three insect larvae (<italic>Galleria mellonella</italic>, <italic>Tenebrio molitor</italic> and <italic>Zophobas morio</italic>) biodegrading polyethylene. The results demonstrated that <italic>G. mellonella</italic> has the best digestion ability on polyethylene. Eating and digestion of plastic products for a long time will inevitably cause negative effects on insects. The additional nutrients can improve the health of the PE-degrading insects, thus extending the digestion time of the plastic. Microbial degradation of polyethylene (PE) products has attracted much attention. Here, two bacterial isolates, <italic>Fictibacillus phosphorivorans</italic> A-2 and <italic>Pseudomonas</italic> sp. A-3 from the gut of PE-feeding <italic>G. mellonella</italic>, was suggested to utilize PE. Two bacterial isolates removed approximately 3.57 ± 0.30% and 2.00 ± 0.16% of PE films after 40 days at 30 ◦C, respectively. We demonstrated the ability for PE degradation of <italic>F. phosphorivorans</italic> A-2 at greater rates than <italic>Pseudomonas</italic> sp. A-3. The results suggest that supplementing the co-diet affected the physiological properties of the PE-degrading insect and plastic biodegradation. This study enriched microbial resources for PE degradation and provided promising evidence for the biodegradation of PE in the environment.