Plastic in the soil, but not as we know it: Biodegradable microplastics rewire carbon storage in farm fields

Nanjing Agricultural University and Bangor University team uncover hidden impacts of biodegradable plastics on soil carbon—led by Dr. Jie Zhou and Dr. Davey L. Jones in landmark study

Biochar Editorial Office, Shenyang Agricultural University

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Biodegradable microplastics decreased plant-derived and increased microbial-derived carbon formation in soil: a two-year field trial
 

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Credit: Xinhu Guo, Wentao Zhang, Yingxin Lu, Haishui Yang, Lingling Shi, Feng-Min Li, Jie Zhou & Davey L. Jones

We often think of plastic pollution as a problem of oceans and seabirds. But beneath our feet, in the quiet dark of agricultural soils, a new kind of contamination is unfolding—one with profound implications for climate, crops, and carbon.

A pioneering two-year field study has revealed that biodegradable microplastics, often hailed as eco-friendly alternatives to conventional plastics, are quietly reshaping the chemistry of farmland soils in unexpected and complex ways. Published on August 22, 2025, in Carbon Research as an open-access original article, this research was co-led by Dr. Jie Zhou from the College of Agriculture at Nanjing Agricultural University, China, and Dr. Davey L. Jones from the School of Environmental and Natural Sciences at Bangor University, UK—a powerful Sino-British collaboration bridging soil science, microbiology, and climate resilience. The team investigated how polypropylene (PP)—a common conventional plastic—and polylactic acid (PLA)—a widely used biodegradable plastic—affect soil organic carbon (SOC) in real-world agricultural conditions. Both were added at realistic concentrations (0.2% w/w) to topsoil (0–20 cm), with an unamended plot serving as control. While neither plastic changed the total amount of carbon stored, the story beneath the surface was dramatically different.

The Biodegradable Paradox: Green Plastic, Complex Consequences

The surprise? PLA—the “eco” plastic—had the strongest impact on carbon composition.

It reduced plant-derived lignin in the soil by 32%, meaning fewer stable carbon compounds from roots and crop residues were being preserved. Why? Because PLA attracted a special group of microbes known as K-strategists—slow-growing, efficient decomposers that specialize in breaking down tough, carbon-rich materials like lignin. “These microbes see PLA as a feast,” explains Dr. Zhou. “But in doing so, they also ramp up enzymes that degrade other stubborn carbon compounds, including those that help lock carbon away long-term.” Yet PLA also boosted microbial necromass—the dead remains of bacteria and fungi—by 35%, a key but often overlooked pathway for carbon storage. This boost came from increased microbial diversity (+5.3%) and more complex microbial networks (+11%), creating a richer, more resilient soil ecosystem. Even more striking: fungal necromass became the dominant player, contributing 24% to SOC under PLA, compared to just 11% with conventional PP. Fungi, it turns out, thrive on PLA and help glue soil particles into stable macroaggregates, physically protecting carbon from decomposition.

The Nitrogen Trap: When Biodegradable Plastics Starve Microbes

But there’s a catch. PLA is rich in carbon but poor in nitrogen—an imbalance that triggers microbial nitrogen limitation. To survive, soil microbes began breaking down their own kind—specifically bacterial necromass, which dropped by 19%. The evidence? A strong negative correlation between bacterial remains and enzymes that scavenge nitrogen from the soil. “In trying to adapt to PLA, microbes start cannibalizing their own biomass,” says Dr. Jones. “It’s a survival strategy, but it could undermine long-term soil fertility and carbon stability.”

Conventional Plastic: A Different Kind of Damage

Meanwhile, polypropylene (PP) told a different story. Rather than altering microbial behavior, it suppressed microbial growth through carbon deprivation and the leaching of toxic additives. This led to reduced synthesis of necromass overall, weakening one of soil’s main carbon storage engines. “PP doesn’t feed the soil—it starves it,” says Dr. Jones. “It’s like putting a blanket over a garden: nothing grows underneath.”

Why This Matters for Climate and Farming

Soil is the second-largest carbon reservoir on Earth—bigger than all the world’s forests combined. How carbon is stored—whether from plants or microbes—determines how long it stays out of the atmosphere. This study shows that even biodegradable plastics can disrupt this delicate balance, shifting carbon storage from plant-based to microbial-based forms, with uncertain long-term consequences. “We can’t assume ‘biodegradable’ means ‘benign’,” warns Dr. Zhou. “In soil, these materials interact with living systems in complex ways we’re only beginning to understand.”

A Triumph of International Soil Science

The collaboration between Nanjing Agricultural University and Bangor University exemplifies the power of global science to tackle pressing environmental challenges.

Dr. Zhou’s expertise in soil biogeochemistry and Dr. Jones’ leadership in microbial ecology have produced one of the most detailed field assessments to date of microplastic impacts on carbon dynamics. The College of Agriculture at Nanjing Agricultural University continues to lead in sustainable agriculture research in China, while Bangor University’s School of Environmental and Natural Sciences remains at the forefront of ecosystem studies in the UK.

The Bottom Line: Rethinking the Future of Farm Plastics

Mulching films, seed coatings, irrigation tapes—plastics are deeply embedded in modern agriculture. As farmers shift toward biodegradable options to reduce pollution, this study serves as a crucial reality check. “Biodegradable plastics aren’t a silver bullet,” says Dr. Zhou. “We need to design them not just to break down, but to break down in ways that support, not disrupt, soil health.” The findings call for smarter regulations, better material design, and a deeper understanding of soil as a living system—not just a growing medium. So the next time you hear “biodegradable,” remember: in the soil, the truth is buried deeper than the plastic itself. And thanks to the work of Dr. Jie Zhou, Dr. Davey L. Jones, and their team, we’re one step closer to uncovering it.

 

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• Title: Biodegradable microplastics decreased plant-derived and increased microbial-derived carbon formation in soil: a two-year field trial
• Keywords: Microplastic; Soil organic carbon; Plant lignin; Microbial necromass; Microbial life strategy
• Citation: Guo, X., Zhang, W., Lu, Y. et al. Biodegradable microplastics decreased plant-derived and increased microbial-derived carbon formation in soil: a two-year field trial. Carbon Res. 4, 61 (2025). https://doi.org/10.1007/s44246-025-00231-7 

 

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About Carbon Research

The journal Carbon Research is an international multidisciplinary platform for communicating advances in fundamental and applied research on natural and engineered carbonaceous materials that are associated with ecological and environmental functions, energy generation, and global change. It is a fully Open Access (OA) journal and the Article Publishing Charges (APC) are waived until Dec 31, 2025. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon functions around the world to deliver findings from this rapidly expanding field of science. The journal is currently indexed by Scopus and Ei Compendex, and as of June 2025, the dynamic CiteScore value is 15.4.

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Journal

Carbon Research

DOI

10.1007/s44246-025-00231-7 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Biodegradable microplastics decreased plant-derived and increased microbial-derived carbon formation in soil: a two-year field trial

Yeast proteins reveal the secrets of drought resistance

Syracuse University

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In this artist rendering of a rehydrated droplet of yeast proteins, blue producer proteins float in the solution allowing them to carry out their function, while the orange energy-guzzling proteins remain in an inactive aggregate.

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Credit: Syracuse University

Our bodies are made up mostly of water. If this water is removed, our cells cannot survive, even when water is reintroduced. But some organisms can completely dry out yet return to life when rehydrated.

A new study in Cell Systems helps explain how organisms can come back from desiccation (the removal of water or moisture) while others fail by looking at the cell’s proteins. In the first survey of its kind, a team of researchers profiled thousands of proteins at once for their ability to survive dehydration and rehydration.

“We are figuring out the rules of what makes a protein tolerant or intolerant to extreme water stress, also known as desiccation,” says Shahar Sukenik, lead author and assistant professor in the Department of Chemistry at Syracuse University. His lab led the study in close collaboration with labs led by co-corresponding authors Stephen D. Fried of Johns Hopkins and Alex Holehouse of Washington University School of Medicine in St. Louis, and with labs at University of Wyoming and University of Utah.

Some proteins appear innately more tolerant to water loss, while others are more fragile, the researchers found. The team used yeast as their model system. The team used mass spectrometry to profile how proteins withstand drying and rehydration. They also deployed AI-driven tools to identify the shapes, chemistries and features of these proteins, revealing the rules of their dehydration tolerance.

“Most proteins will lose over three-quarters of their copies following a dehydration-rehydration cycle,” says Sukenik, “but some proteins do much better, with a large majority of their copies surviving the process.”

The proteins that survived water loss tended to be smaller, tightly folded, with fewer interactions and distinct surface chemistry. One key trait was a high number of negative charges on the surface of tolerant proteins, which seems to protect them during drying and after rehydration.

The team then used these chemical rules to increase the dehydration tolerance of a protein. They focused on the Green Fluorescent Protein—GFP—which in its original form is not tolerant to dehydration. By introducing targeted mutations, the researchers managed to increase the dehydration tolerance of GFP such that nearly 100% of the proteins remained active following rehydration. The team is currently applying this strategy to design novel, dehydration resistant proteins.

Protecting producer proteins

The study also revealed a pattern in the function of proteins that survived and those that did not.

“The most tolerant proteins not only have a specific surface chemistry, but also happen to have very specific functions,” says Sukenik.

Resilient proteins were typically ones that are responsible for creating small molecules, the essential building blocks of the cells.

“Everything starts from these small building blocks, which are then used to create larger biomolecules, including other proteins,” says Sukenik. “If the cell runs out of these small building blocks for whatever reason, that’s it. The cell is stuck. It’s like a car running out of gas.”

Dehydration sensitive proteins, by contrast, were typically involved in energy-costly jobs, such as making ribosomes, which are the cell’s protein factories.

Yeast cells appear to gain an evolutionary advantage during dehydration by protecting the proteins that produce their building blocks. At the same time, they get rid of the proteins that consume these building blocks at a rapid pace. This differentiation allows yeast cells to slowly return to an optimal resource balance when water returns.

“We think these ‘producer’ proteins have evolved to develop the specific chemistry that allows them to rehydrate, so when water hits the dehydrated cell they kick into action and enrich the environment with the building blocks they produce,” Sukenik says.

Language of survival

This work could reframe current thinking about biological survival strategies. Dehydration tolerance may not be limited to a few hardy species. Instead, this ability could reflect an underlying “grammar” written into the chemistry of proteins, the researchers note. By revealing that grammar, the team is not only explaining how life adapts to stress, but also using those strategies towards novel protein design.

The researchers envision potential applications in biotechnology, such as engineering proteins for longer shelf life in therapeutics and food. Protein-based medicines—such as insulin or antibodies—could be stored and transported without refrigeration, significantly extending their shelf life and making them easier to distribute, especially in areas where cold storage is difficult. This approach could make protein therapeutics more accessible and reliable.

“During the COVID-19 pandemic, there were problems in cold chain delivery which hindered access to vaccines,” says Sukenik. “But when your product is dehydrated, you won’t have to keep it cold. The shelf life of medicines, food, or other protein-based products could be extended by months or even years.”

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Journal

Cell Systems

Article Publication Date

6-Oct-2025

 

Turning biogas waste into a powerful tool for cleaning ammonium pollution

Biochar Editorial Office, Shenyang Agricultural University

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Improved adsorption capacity of ammonium from aqueous solution by modified biogas residue biochar
 

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Credit: Ping Cong, Shuhui Song, Yanmei Zhu, Xinwei Ji, Shuai Liu, Shuai Kuang, Yanli Xu, Qiuqiang Hou, Xuebo Zheng & Wenjing Song

Researchers in China have developed a modified biochar made from biogas residue that can efficiently remove ammonium nitrogen from water, offering a low-cost and sustainable solution to agricultural pollution.

Ammonium nitrogen, a common pollutant from fertilizers and livestock operations, often leaches into waterways, contributing to eutrophication and groundwater contamination. Using biochar—a carbon-rich material produced by heating organic waste—scientists have long sought to trap these pollutants before they reach the environment. However, traditional biochar has shown limited adsorption capacity.

A new study published in Biochar reports that chemical modification of biogas residue biochar using potassium permanganate, hydrogen peroxide, and sodium hydroxide dramatically enhances its ability to capture ammonium. The team led by Dr. Xuebo Zheng and Dr. Wenjing Song at the Tobacco Research Institute, Chinese Academy of Agricultural Sciences, found that potassium-permanganate-modified biochar achieved an adsorption capacity up to four times greater than unmodified biochar.

“By improving the pore structure and surface chemistry of biochar, we created more active sites for ammonium ions to attach,” said Dr. Zheng. “This simple modification transforms agricultural waste into an efficient adsorbent for water purification.”

Microscopic analysis revealed that potassium permanganate treatment produced a richer network of micro- and mesopores, substantially increasing surface area and enhancing pore-based adsorption. In contrast, hydrogen peroxide and sodium hydroxide primarily boosted oxygen-containing functional groups on the biochar surface, contributing to electrostatic attraction of ammonium ions.

Among all treatments, the potassium permanganate-modified biochar showed the highest performance, achieving a maximum adsorption capacity of 68.15 milligrams per gram under laboratory conditions. This improvement highlights the importance of optimizing pore structure over merely increasing surface functional groups.

The findings demonstrate a promising strategy to recycle biogas residues—a byproduct of renewable energy production—into high-value materials for environmental remediation. “Our work offers a pathway to manage waste and mitigate water pollution at the same time,” said Dr. Song.

The research underscores how small chemical changes to biochar can significantly influence its environmental applications. With further testing in field conditions, the modified biogas residue biochar could provide farmers and wastewater managers a practical tool to prevent nitrogen loss and protect freshwater ecosystems.

 

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Journal Reference: Cong, P., Song, S., Zhu, Y. et al. Improved adsorption capacity of ammonium from aqueous solution by modified biogas residue biochar. Biochar 7, 97 (2025). https://doi.org/10.1007/s42773-025-00500-z 

 

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About Biochar

Biochar is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field. 

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Journal

Biochar

DOI

10.1007/s42773-025-00500-z 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Improved adsorption capacity of ammonium from aqueous solution by modified biogas residue biochar

Artificially sweetened and sugary drinks are both associated with an increased risk of liver disease, study finds

A major new study reveals that both sugar-sweetened beverages (SSBs) and low- or non-sugar-sweetened beverages (LNSSBs) are significantly associated with a higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD).

Beyond

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Artificially sweetened and sugary drinks are both associated with an increased risk of liver disease, study finds

(Berlin, Germany, Tuesday, 7 October 2025) A major new study reveals that both sugar-sweetened beverages (SSBs) and low- or non-sugar-sweetened beverages (LNSSBs) are significantly associated with a higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD).1

The study, presented today at UEG Week 2025, followed 123,788 UK Biobank participants without liver disease at baseline. Beverage consumption was assessed using repeated 24-hour dietary questionnaires. Researchers examined the associations between SSB and LNSSB intake and the risks of developing MASLD, liver fat accumulation and liver-related mortality.

A higher intake of both LNSSBs and SSBs (>250g per day) was associated with a 60% (HR: 1.599) and 50% (HR: 1.469) elevated risk of developing MASLD, respectively. Over the median 10.3-year follow-up, 1,178 participants developed MASLD and 108 died from liver-related causes. While no significant association was observed for SSBs, LNSSB consumption was additionally linked to a higher risk of liver-related mortality. Both beverage types were also positively associated with higher liver fat content.

MASLD, formally known as non-alcoholic fatty liver disease (NAFLD), is a condition where fat accumulates in the liver, which overtime can cause inflammation (hepatitis) and symptoms such as pain, fatigue and loss of appetite.2 The disease has emerged as a global health burden since being recognised as the most common chronic liver disease, with experts estimating that it affects over 30% of people worldwide and is a rapidly increasing cause of liver-related deaths.3

Lead author of the study, Lihe Liu, commented, “SSBs have long been under scrutiny, while their ‘diet’ alternatives are often seen as the healthier choice. Both, however, are widely consumed and their effects on liver health have not been well understood.”

“Our study shows that LNSSBs were actually linked to a higher risk of MASLD, even at modest intake levels such as a single can per day. These findings challenge the common perception that these drinks are harmless and highlight the need to reconsider their role in diet and liver health, especially as MASLD emerges as a global health concern.”

Liu noted the potential biological mechanisms that may underlie the observed risks, “The higher sugar content in SSBs can cause rapid spikes in blood glucose and insulin, promote weight gain and increase uric acid levels, all of which contribute to liver fat accumulation. LNSSBs, on the other hand, may affect liver health by altering the gut microbiome, disrupting the feeling of fullness, driving sweet cravings and even stimulating insulin secretion.”

The authors emphasised that these findings support limiting both SSBs and LNSSBs as part of a comprehensive prevention strategy, targeting not only liver disease but also cardio-renal-metabolic health. Replacing either beverage with water significantly reduced MASLD risk – by 12.8% for SSBs and 15.2% for LNSSBs – while substitution between the two types of beverages offered no risk reduction.

Liu added, “The safest approach is to limit both sugar-sweetened and artificially sweetened drinks. Water remains the best choice as it removes the metabolic burden and prevents fat accumulation in the liver, whilst hydrating the body.”

The researchers now aim to explore causal mechanisms more deeply through long-term, randomised and genetic trials with a focus on how sugar and its substitutes interact with the gut microbiome and influence liver disease.

END

Notes to editors:

For further information or to arrange an expert interview, please contact media@ueg.eu

We kindly ask that a reference to UEG Week 2025 is included when communicating any information within this press release.

About the author:

Lihe Liu is a graduate student in the Department of Gastroenterology at the First Affiliated Hospital of Soochow University, Suzhou, China. Her research focuses on metabolic liver diseases and gastroenterology, where she applies data-driven approaches using R and Python to support clinical research.

About UEG:

Founded in 1992, United European Gastroenterology (UEG) is the leading non-profit organisation for excellence in digestive health in Europe and beyond with its headquarters in Vienna. We improve the prevention and care of digestive diseases in Europe through providing top tier education, supporting research and advancing clinical standards.

As Europe’s home and umbrella for multidisciplinary gastroenterology, we unite over 50,000 engaged professionals from national and specialist societies, individual digestive health experts and related scientists from all fields and career stages. Over 30,000 digestive healthcare professionals from around the world have joined the UEG Community as UEG Associates and UEG Young Associates. The UEG Community enables digestive health professionals from across the globe to become UEG Associates and thereby connect, network and benefit from a wide range of free resources and educational activities.

Find out more about UEG’s work by visiting: https://ueg.eu/

References:

1. Liu, L et al. Sugar- and low/non-sugar-sweetened beverages and risks of metabolic dysfunction-associated steatotic liver disease and liver-related mortality: A prospective analysis of the UK Biobank. Presented at UEG Week 2025; 7 October 2025; Berlin, Germany.
2. Girish, V. and John, S. Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). (2025). PMID: 31082077
3. Younossi, Z. M. et al. The global epidemiology of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH): a systematic review. (2023). Journals. DOI: 10.1097/HEP.0000000000000004