Harnessing fungi and bacteria to speed up the biodegradation of plastic mulch films.
Munhoz DR, Meng K, Merloti LF, Geissen V, Zhang J
Soil Health
The plastic sheeting stretched over garden beds and farm rows each season rarely disappears cleanly — but molds already working in your compost pile may be capable of breaking down the fragments left behind in the soil.
Researchers found that certain molds — the same kind already working in compost piles — can attack and partially dissolve the plastic films farmers and gardeners stretch over beds each season. Pairing those molds with specific bacteria sped the breakdown further under some conditions. The surprising catch: a plastic blend widely marketed as 'biodegradable' didn't break down any faster than regular plastic, which matters for anyone choosing mulch materials.
Key Findings
An Aspergillus mold consortium achieved up to 3.71% weight loss and reduced polymer chain length by 17.2 kDa in standard polyethylene mulch film over 180 days — measurable structural breakdown, not just surface wear.
Compost-native microbes (Gordonia, Thermomyces, Mycobacterium) combined with Aspergillus reached 4.91% weight loss in additive-free polyethylene mulch when the plastic was pre-treated with mineral oil, suggesting pre-treatment primes plastic for microbial attack.
The 'biodegradable' PBAT-PLA mulch blend degraded more slowly than expected across all treatments, raising questions about whether biodegradable labeling reflects real-world agricultural breakdown rates.
chevron_right Technical Summary
Scientists tested specific mold and bacterial combinations to accelerate the breakdown of polyethylene plastic mulch films used in agriculture. Aspergillus mold treatments achieved meaningful degradation of standard plastic mulch — up to 4.91% weight loss over 180 days — while a mulch marketed as biodegradable broke down more slowly than conventional plastic.
Abstract Preview
Plastics and microplastics are pervasive in agricultural systems, underscoring the need for effective mitigation strategies. Here, we explored microbial treatments to accelerate the degradation of ...
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