Natural leaf coatings may help hydrochar lock away carbon more effectively
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Alkyl carbon in a hydrophobic coating enhances the chemical stability of hydrochar
view moreCredit: Jianping Fan, Fangfang Li, Qingkong Chen, Peiwen Zeng, Yanlin Li, Wei Chen, Qiangbin Yang & Hong Yang
A naturally formed water repellent coating on hydrochar could play an overlooked role in protecting carbon from chemical degradation, according to a new study examining hydrochar made from several common plant leaves. The findings suggest that hydrophobic alkyl carbon derived from plant waxes and cutin can act as a protective surface layer, potentially improving the ability of hydrochar to retain carbon in soil.
“The hydrophobic alkyl carbon coating may strengthen hydrochar stability in soil, which is expected to promote its capacity for soil carbon sequestration,” the authors concluded.
Hydrochar is a carbon rich material produced by heating biomass in water under elevated temperature and pressure. Because this hydrothermal carbonization process can handle wet biomass without energy intensive drying, hydrochar is increasingly being explored for soil remediation, pollution control, and carbon sequestration. However, its long term environmental value depends strongly on how resistant its carbon is to degradation.
Researchers led by Jianping Fan and Fangfang Li investigated an often overlooked feature of hydrochar: a hydrophobic coating that can form on its surface during hydrothermal carbonization. They produced hydrochar from corn leaves, lotus leaves, palm leaves, and pine needles, then examined the chemical composition, surface characteristics, thermal behavior, and resistance to chemical oxidation before and after removing the coating.
The researchers found that the coating was closely linked to the natural cuticle that covers plant leaves. Lotus leaf hydrochar had the most hydrophobic coating, dominated by nonacosane-4,10-diol originating mainly from leaf wax. In contrast, coatings on hydrochar made from corn leaves, palm leaves, and pine needles were dominated by palmitic acid or 16-hydroxypalmitic acid, compounds associated with the breakdown of cutin.
Importantly, greater coating hydrophobicity was associated with higher levels of alkyl carbon in the hydrochar. When the coating was removed with acetone, alkyl carbon content declined while previously covered pores became exposed, increasing the material's accessible surface area.
Removing the coating produced a surprising contrast between thermal and chemical stability. Overall thermal stability changed little, because increases in the energy required for thermal decomposition were counterbalanced by increases in molecular reaction frequency.
Chemical stability told a different story. The coating acted as a physical and chemical barrier, covering reactive sites, blocking pores, and limiting contact between oxidizing agents and the underlying carbon. After the coating was removed, the carbon loss of lotus leaf, palm leaf, and pine needle hydrochars during chemical oxidation increased by 10.13% to 16.01%. The lotus leaf hydrochar, which had the strongest hydrophobic coating, showed the greatest loss of protection after coating removal.
The results also challenge the idea that bulk properties such as aromatic carbon content alone are sufficient to predict hydrochar stability. Surface coatings and their chemical composition can substantially influence how hydrochar responds to environmental oxidation.
The study provides new insight into how the original biological structures of plant materials can continue to influence carbon stability even after hydrothermal processing. Understanding these surface effects could help researchers select suitable biomass feedstocks and design more stable hydrochars for long term soil carbon storage and environmental applications.
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Journal reference: Fan J, Li F, Chen Q, Zeng P, Li Y, et al. 2026. Alkyl carbon in a hydrophobic coating enhances the chemical stability of hydrochar. Environmental and Biogeochemical Processes 2: e016 doi: 10.48130/ebp-0026-0012
https://www.maxapress.com/article/doi/10.48130/ebp-0026-0012
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About the Journal:
Environmental and Biogeochemical Processes (e-ISSN 3070-1708) is a multidisciplinary platform for communicating advances in fundamental and applied research on the interactions and processes involving the cycling of elements and compounds between the biological, geological, and chemical components of the environment.
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Journal
Environmental and Biogeochemical Processes
Method of Research
Experimental study
Article Title
Alkyl carbon in a hydrophobic coating enhances the chemical stability of hydrochar
Article Publication Date
17-Aug-2026
Native microbial team helps acidic soil recover while boosting crop growth
Scientists build a synthetic community of native soil bacteria that raises soil pH, improves nutrient cycling, and supports healthier plant growth
Shenyang Agricultural University Collaborative Journals
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Mechanism of synthetic communities in improving acidic soil and promoting crop growth
view moreCredit: Qun Rong, Siting Lu, Jingyun Huang, Junrong Wei, Zengyu Zhang, Shu Yang, Chaolan Zhang & Xiaofeng Li
Acidic soils can make it difficult for crops to obtain nutrients and thrive. Now, researchers have developed a small, carefully selected community of native soil bacteria that can reduce acid stress while helping plants access essential nutrients.
“Instead of introducing microorganisms that may struggle to survive in a new environment, we wanted to use native bacteria that are already adapted to the challenging conditions of acidic, nutrient-poor soils,” said Xiaofeng Li, corresponding author of the study. “Our results show that these microorganisms can work together to improve the soil environment and promote plant growth through several complementary biological processes.”
Soil acidification is a major challenge for agriculture. Low soil pH can reduce nutrient availability, disrupt microbial communities, and interfere with the biological processes that support healthy crops. Conventional approaches can improve acidic soils, but the researchers investigated whether naturally adapted microorganisms could provide another sustainable tool.
The team collected microorganisms from the rhizosphere, the narrow zone of soil surrounding plant roots, in strongly acidic red soil in Guangxi, China. By gradually reducing the amount of available carbon during laboratory enrichment, they selected microorganisms capable of surviving under both acidic and carbon-limited conditions.
Two promising strains, Paracoccus communis C4 and C5, were combined to form a synthetic microbial community, or SynCom. The community showed strong acid tolerance and produced alkaline substances as well as indole-3-acetic acid, or IAA, a plant hormone associated with root development. In laboratory cultures, the SynCom reached a pH of 8.3 and produced 35.53 mg/L of IAA.
To help the bacteria survive after application to soil, the researchers used filter mud, an organic byproduct of sugarcane processing, as a microbial carrier. They then tested the resulting microbial amendment in greenhouse pots planted with lettuce.
After treatment, the SynCom successfully colonized the rhizosphere and increased rhizosphere soil pH from 4.73 to 5.50. Lettuce plants also showed marked improvements. Compared with untreated plants, those receiving the SynCom treatment had 120.60% greater height, 527.83% higher fresh weight, and 33.80% higher chlorophyll content.
The benefits extended below ground. The treatment promoted lateral root development, increased root length and surface area, and improved the availability of nutrients, including nitrogen.
Metagenomic analysis revealed another important effect. The SynCom reshaped microbial functions involved in carbon, nitrogen, and phosphorus cycling. The abundance of cbbL, a gene associated with microbial carbon fixation, increased approximately 25-fold compared with the untreated control. Genes linked to nitrogen fixation, ammonium production, phosphorus solubilization, and phosphorus transport were also enhanced.
Together, these changes suggest that the microbial community does more than simply neutralize acidity. It can help create a more biologically active rhizosphere where carbon sequestration, nutrient cycling, and plant growth reinforce one another.
The findings offer a potential framework for developing microbial biofertilizers tailored to acidic and nutrient-deficient farmland. Because the approach uses native microorganisms and an agricultural byproduct as a carrier, it may also support more resource-efficient soil management.
The researchers note that the current results come from controlled pot experiments. Future studies will evaluate how well the SynCom performs under real field conditions and determine its broader potential for sustainable agricultural production.
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Journal Reference: Rong Q, Lu S, Huang J, Wei J, Zhang Z, et al. 2026. Mechanism of synthetic communities in improving acidic soil and promoting crop growth. Agricultural Ecology and Environment 2: e020 doi: 10.48130/aee-0026-0018
https://www.maxapress.com/article/doi/10.48130/aee-0026-0018
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About Agricultural Ecology and Environment:
Agricultural Ecology and Environment (e-ISSN 3070-0639) is a multidisciplinary platform for communicating advances in fundamental and applied research on the agroecological environment, focusing on the interactions between agroecosystems and the environment. It is dedicated to advancing the understanding of the complex interactions between agricultural practices and ecological systems. The journal aims to provide a comprehensive and cutting-edge forum for researchers, practitioners, policymakers, and stakeholders from diverse fields such as agronomy, ecology, environmental science, soil science, and sustainable development.
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Journal
Agricultural Ecology and Environment
Method of Research
Experimental study
Article Title
Mechanism of synthetic communities in improving acidic soil and promoting crop growth
Machine learning reveals elemental clues behind persistent free radicals in biochar
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Elemental composition-based prediction of persistent free radicals concentration and g-Factor in lignocellulose-derived biochar combining interpretable machine learning and experimental analysis
view moreCredit: Linjian Gao, Chengcheng Xu, Mengzi Li, Zhongda Xu & Wenmei Tao
A new study combines interpretable machine learning with laboratory experiments to uncover how the elemental composition of biochar influences persistent free radicals, offering a potential tool for predicting biochar reactivity and environmental risks.
Biochar, a carbon-rich material produced by heating biomass under oxygen-limited conditions, is widely studied for applications ranging from soil improvement to pollution control. Yet biochar can also contain persistent free radicals, or PFRs, which may remain stable for days or months. These radicals can help generate reactive oxygen species that break down pollutants, but they may also contribute to oxidative stress in living organisms.
Understanding what controls these radicals is therefore important for designing biochar that is both effective and environmentally responsible.
Researchers from Kunming University of Science & Technology analyzed published data using six machine-learning approaches, including XGBoost, gradient boosting, support vector regression, a shallow neural network, random forest, and ensemble learning. They then used interpretable machine-learning tools to determine which elemental properties most strongly influenced PFR concentration and radical type.
The analysis identified the hydrogen-to-carbon ratio, or H/C, and oxygen content as the most important descriptors of PFR concentration. Oxygen content and the oxygen-to-carbon ratio, or O/C, were the strongest predictors of the g-Factor, a measurement used to distinguish different types of free radicals.
"Our results show that relatively simple elemental information can provide valuable clues about the behavior of persistent free radicals in biochar," said Wenmei Tao, corresponding author of the study. "Combining interpretable machine learning with experimental validation may help us better understand how these radicals form and ultimately support more informed biochar design and environmental risk assessment."
The researchers assembled 263 paired records of PFR concentration and g-Factor from previously published studies. The best-performing models achieved test R² values of 0.7797 for PFR concentration and 0.7647 for g-Factor. The models were also highly effective at distinguishing samples with relatively high and low values, with ROC-AUC values exceeding 0.96.
Interpretable analyses provided further insight into the relationships behind those predictions. Lower H/C values and lower oxygen content were generally associated with higher PFR concentrations. In contrast, increasing oxygen content and O/C tended to increase the g-Factor, indicating a shift toward oxygen-centered radicals.
These patterns suggest that changes in elemental composition during biomass pyrolysis are closely connected to both the amount and type of persistent free radicals formed in biochar.
To test whether the machine-learning findings held up experimentally, the researchers produced biochars from cellulose, lignin, peanut hull, rice straw, and pine sawdust at different pyrolysis temperatures. Independent measurements supported the major trends predicted by the models. Spearman correlation analysis confirmed that H/C and oxygen content were most strongly associated with PFR concentration, while oxygen content and O/C showed the strongest relationships with g-Factor.
The researchers also found that when O/C values were similar, higher hydrogen content was associated with a higher g-Factor, revealing an additional interaction that would be difficult to identify using simple linear relationships alone.
The study provides a data-driven framework for linking readily measurable elemental properties to the behavior of persistent free radicals in lignocellulose-derived biochar. The findings could help researchers better evaluate PFR-related environmental risks and guide the development of biochars with properties tailored for environmental remediation.
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Journal reference: Gao L, Xu C, Li M, Xu Z, Tao W. 2026. Elemental composition-based prediction of persistent free radicals concentration and g-Factor in lignocellulose-derived biochar combining interpretable machine learning and experimental analysis. Biochar X 2: e022 doi: 10.48130/bchax-0026-0020
https://www.maxapress.com/article/doi/10.48130/bchax-0026-0020
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About the Journal:
Biochar X (e-ISSN: 3070-1686) is an open access, online-only journal aims to transcend traditional disciplinary boundaries by providing a multidisciplinary platform for the exchange of cutting-edge research in both fundamental and applied aspects of biochar. The journal is dedicated to supporting the global biochar research community by offering an innovative, efficient, and professional outlet for sharing new findings and perspectives. Its core focus lies in the discovery of novel insights and the development of emerging applications in the rapidly growing field of biochar science.
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Journal
Biochar X
Method of Research
Experimental study
Article Title
Elemental composition-based prediction of persistent free radicals concentration and g-Factor in lignocellulose-derived biochar combining interpretable machine learning and experimental analysis
Article Publication Date
17-Aug-2026
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