Not all compostable plastics break down at the same speed
Kundu P, Muhammed M, G A, C A, Pm S
Composting
That 'compostable' plastic bag or fork you toss in your backyard bin might sit there far longer than you think, since some biopolymers only fully break down under the hot, controlled conditions of industrial composting.
Researchers buried different types of 'plant-based' plastics, like PLA and PBS, in compost and tracked how fast microbes broke them down at different temperatures. PLA film disappeared the fastest, losing structure and crystallinity within weeks, while PBS pellets and some commercial bioplastics degraded much more slowly, even under ideal hot composting conditions.
Key Findings
PLA film showed the highest weight loss (>3%) and fastest biodegradation, following the order PLA film > PLA pellets > bioplastic > PBS pellets
Thermophilic (hot) composting conditions boosted biodegradation efficiency to roughly 69%, with compost recipe C3 performing best overall
X-ray analysis showed degraded biopolymers lost crystalline structure, and biodegradation followed the Hill kinetic model with very high accuracy (R2 ≥ 0.99); Bacillota bacteria were identified as key degraders
chevron_right Technical Summary
Scientists tested how well 'compostable' plastics like PLA and PBS actually break down in real composting conditions, finding that PLA film degrades fastest (over 69% under hot, thermophilic conditions) while PBS pellets lag behind, meaning not all bioplastics are equally ready for your compost bin.
Abstract Preview
Original paper
Study on biodegradation dynamics of biopolymers under aerobic composting environment.
Biodegradation of biopolymers, which included, PLA (polylactic acid) pellets, PLA film, PBS (polybutylene succinate) pellets, and commercial bioplastics, were studied at various temperatures (40-60...
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