As global pollution intensifies, scientists are searching for cleaner and more sustainable ways to restore contaminated soil and water. A new review highlights how an unexpected partnership between biochar, microbes, and microbial secretions could offer a powerful solution.
Researchers report that biochar, a carbon-rich material produced from biomass, can work together with microorganisms and their extracellular polymeric substances, or EPS, to significantly improve environmental remediation. These interactions not only help remove toxic pollutants but also enhance soil health and fertility.
“Biochar provides a unique habitat and functional platform for microorganisms, while microbial EPS acts as a bridge that strengthens these interactions,” the authors explain. “Together, they create a synergistic system that improves pollutant removal and supports ecosystem recovery.”
Biochar is widely recognized for its porous structure and large surface area, which allow it to adsorb harmful substances such as heavy metals and organic pollutants. At the same time, microorganisms play a central role in breaking down contaminants through natural biological processes. EPS, which are sticky, gel-like substances secreted by microbes, help microbes attach to surfaces, form biofilms, and communicate with each other.
According to the review, the combination of these three components creates a highly efficient system for environmental cleanup. Biochar acts as both a shelter and a support structure for microbial communities. Its surface provides sites where microbes can attach and grow, while its chemical properties help retain nutrients and pollutants.
EPS further enhances this system by forming a protective matrix around microbial cells. This matrix improves microbial survival under stressful conditions and increases their ability to capture and transform pollutants. In addition, EPS facilitates communication between microbes and supports electron transfer processes that are essential for pollutant degradation.
The study identifies four key mechanisms behind these interactions. First, adhesion and interfacial processes allow microbes and EPS to attach to biochar surfaces. Second, biochar provides shelter and nutrients that support microbial growth. Third, signaling and bioregulation enable communication within microbial communities. Finally, electron transfer processes between microbes and biochar enhance metabolic activity and pollutant breakdown.
These mechanisms have important real-world applications. The combined system has been shown to improve the removal of heavy metals such as lead and cadmium, as well as organic contaminants including antibiotics, dyes, and pesticides. In wastewater treatment, the approach can enhance nitrogen removal efficiency by supporting specialized microbial processes. In agriculture, it can improve soil structure, increase nutrient availability, and promote plant growth.
The review also highlights that EPS plays a critical but often overlooked role. By acting as both a structural and functional mediator, EPS enhances the stability and effectiveness of the biochar microbial system.
Despite these promising findings, the researchers note that important questions remain. Long-term impacts on microbial communities, optimal biochar design, and the precise role of EPS in different environments require further investigation.
Still, the study provides a comprehensive framework for understanding how biochar and microbes interact, offering new insights for sustainable environmental management.
“This integrated system represents a promising direction for future remediation technologies,” the authors conclude. “By harnessing natural processes, we can develop more efficient and environmentally friendly strategies to address global pollution challenges.”
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Journal Reference: Kayoumu, M., Wang, H. & Duan, G. Interactions between microbial extracellular polymeric substances and biochar, and their potential applications: a review. Biochar 7, 62 (2025).
https://doi.org/10.1007/s42773-025-00452-4
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About Biochar
Biochar (e-ISSN: 2524-7867) 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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