Comparing the bacterial composition, succession and assembly patterns in plastisphere and kitchen waste composting with PLA/PBAT blends

Biodegradable plastics has aroused increasing concern due to the negative environmental impact of plastic waste, however, the impact of biodegradable plastics mixed into kitchen waste (KW) on composting remains poorly understood, especially focusing on bacterial communities in the unique plastisphere. Here, KW composting for 120 days with adding poly lactic acid / poly butylene adipate-co-terephthalate (PLA/PBAT) plastics were con-ducted to reveal the dynamics of bacterial composition, succession, and assembly process in different ecological niches (compost and plastisphere). Results showed that the existence of PLA/PBAT plastics in composting would not significantly affect the safety and maturation of composts. After composting, 80% PLA/PBAT were degraded and there were prominent divergences of bacterial compositions between plastisphere, composts with PLA/PBAT and control. Co-occurrence network suggested that PLA/PBAT plastisphere exhibited higher network complexity and cohesion than that in compost, and PLA/PBAT increased bacterial module hubs, network hubs, and con-nectors in composting compared to control, but might enrich pathogens. Phylogenetic bin-based null model analysis indicated that stochastic processes obviously shaped the communities on PLA/PBAT plastisphere, but compare to control, PLA/PBAT plastics enhanced the contribution of deterministic processes on composting bacterial community assembly. These findings deeply understood the assembly patterns and diversity of plas-tisphere and composting processes, laying down a foundation on applying biodegradable plastics under the classification of domestic garbage.

Automated summary

The dynamics of bacterial composition, succession, and assembly process in different ecological niches (compost and plastisphere) were revealed during kitchen waste composting with the addition of poly lactic acid / poly butylene adipate-co-terephthalate (PLA/PBAT) plastics for 120 days. The results showed that the presence of PLA/PBAT plastics did not significantly affect the safety and maturation of composts, but there were notable differences in bacterial compositions between the plastisphere and composts with PLA/PBAT. The PLA/PBAT plastics may enhance the contribution of deterministic processes on composting bacterial community assembly while enriching pathogens.