Bioaugmentation influences PBAT biodegradation patterns during composting through associated shifts in plastisphere...

Area of Science:

• Environmental Microbiology
• Polymer Science
• Biotechnology

Background:

• The plastisphere microbiome's role in bioplastic biodegradation during composting is crucial but not fully understood.
• Poly(butylene adipate-co-terephthalate) (PBAT) is a common biodegradable plastic whose composting efficiency needs optimization.

Purpose of the Study:

• To investigate the biodegradation of PBAT by examining surface changes and microbial community shifts under composting conditions.
• To evaluate the impact of inoculant amendment on PBAT degradation and plastisphere microbial succession.

Main Methods:

• Simulated industrial aerobic composting of PBAT.
• Surface physicochemical characterization (e.g., water contact angle, FTIR spectroscopy).
• High-throughput microbial 16S rRNA gene sequencing.
• Gel permeation chromatography (GPC) for molecular weight analysis.

Main Results:

• Inoculant amendment significantly increased PBAT carbon loss (12.7%) compared to controls (3.2%).
• PBAT underwent depolymerization, evidenced by decreased molecular weight (Mz) and accelerated ester bond hydrolysis.
• Microbial profiling revealed increased alpha-diversity and enrichment of thermophilic taxa, with distinct hydrolytic and oxidative genera dominating different composting phases.

Conclusions:

• Inoculant addition effectively enhances PBAT biodegradation by restructuring the plastisphere microbiome.
• Composting involves stage-dependent microbial contributions, influencing PBAT depolymerization and surface modification.
• Findings provide a framework for understanding biopolymer-microbe interactions and optimizing inoculant-assisted bioplastic composting.