We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
PHA Microplastic Aging Decreases N2O Sink Capacity: Released γ-Butyrolactone Decouples Denitrifying Electron Transfer and Oxidative Phosphorylation
AI summary Read the abstract
Researchers found that aging of biobased polyhydroxyalkanoate microplastics releases a compound called gamma-butyrolactone that impairs the ability of soil bacteria to consume nitrous oxide, a potent greenhouse gas. The released compound disrupted the coupling between electron transfer and energy production in denitrifying bacteria, reducing their capacity to break down nitrous oxide. The study reveals an unexpected mechanism by which biodegradable microplastic aging could worsen greenhouse gas emissions from soil.
Bacterial denitrification is a main pathway for soil N2O sinks, which is crucial for assessing and controlling N2O emissions. Biobased polyhydroxyalkanoate (PHA) microplastic particles (MPs) degrade slowly in conventional environments, remaining inert for extended periods. However, the impacts of PHA microplastic aging on the bacterial N2O sink capacity before degradation remain poorly understood. Here, the soil model strain Paracoccus denitrificans was exposed to 0.05-0.5% (w/w) virgin and aged PHA MPs. Although no significant changes in the molecular weights were observed, aged PHA MPs hindered cell growth and N2O reduction rates, leading to a surge in N2O emissions. 1H NMR spectroscopy and UPLC-QTOF-MS analysis identified γ-butyrolactone as the key component released from aged PHA MPs. Metabolic verifications at the cellular level confirmed its inhibition on the N2O sink and ATP synthesis. The γ-butyrolactone that protonated and hydrolyzed spontaneously in the periplasm would compete for protons with ATPase and destroy the coupling between denitrifying electron transfer and oxidative phosphorylation. Consequently, energy-deficient cells reduced the electron supply for N2O reduction, which did not contribute to energy conservation. This work unveils a novel mechanism by which PHA microplastic aging impairs the bacterial N2O sink and highlights the need to consider environmental risks posed by biobased microplastic aging.
More Papers Like This
Plastisphere-mediated nitrogen cycling and N2O emissions in inland waters: A systematic review
AI summary Read the abstract
Researchers synthesized evidence that microplastic biofilms in freshwater systems selectively enrich nitrifying and denitrifying bacteria while suppressing the gene responsible for converting nitrous oxide to nitrogen gas, creating conditions that amplify N₂O emissions — with biodegradable plastics posing an unexpectedly complex greenhouse gas risk.
Perfluorooctanoic acid and concomitant microplastics pollution impact nitrogen elimination processes and increase N2O emission in wetlands through regulation of the functional microbiome
AI summary Read the abstract
This study found that the industrial chemical PFOA, when combined with microplastics, significantly disrupts nitrogen processing in wetlands and increases emissions of the potent greenhouse gas nitrous oxide. Researchers observed that PFOA alone inhibited important nitrogen-removal processes, and the addition of microplastics, especially biodegradable PLA plastic, made the problem worse. The findings suggest that combined pollution from forever chemicals and microplastics may be undermining the natural water-cleaning ability of wetland ecosystems.
Microplastic composition-dependent effects on N2O emissions driven by changes in soil N process and microbial communities
AI summary Read the abstract
This study found that biodegradable and conventional microplastics both reduced nitrous oxide emissions from plant-soil systems by 17-32%, but through different mechanisms: polyethylene promoted complete denitrification, PLA suppressed a key denitrification gene, and PBAT inhibited both nitrification and denitrification. A companion meta-analysis of 14 plant-soil studies confirmed that microplastics reduce N2O emissions by an average of 22% in vegetated systems.
Divergent effects of biodegradable and conventional microplastics on denitrification in soils: Mechanisms governing N₂O emission and product stoichiometry
AI summary Read the abstract
Microplastics from farm soils don't just pollute the land, they may also be quietly fueling climate change. This study found that "conventional" plastics (the everyday, non-biodegradable kind) cause soil bacteria to release more nitrous oxide, a greenhouse gas nearly 300 times more potent than CO₂, while so-called "biodegradable" plastics can trigger a different pollution problem by increasing another harmful gas under wet conditions. The takeaway: not all plastics behave the same way once they're in soil, so the "biodegradable" label doesn't guarantee a cleaner environmental outcome, espec
Polylactic acid microplastics increase N2O emissions from mainstream biological nitrogen removal systems: overlooked concern.
AI summary Read the abstract
"Biodegradable" plastics are often marketed as eco-friendly, but this study found that microplastics from one common type (PLA, used in things like compostable cups and food packaging) actually disrupt wastewater treatment plants' ability to remove nitrogen from sewage, causing them to release more nitrous oxide, a potent greenhouse gas. This matters because it shows that switching to "biodegradable" plastics isn't necessarily a clean fix; these particles can still end up in our water systems and cause unexpected environmental problems, even if they eventually break down.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.