In a comprehensive literature review published in the journal Sustainability Science and Technology, lead author Clara Matte Borges Machado and her research team at the Federal University of Paraná explore a revolutionary waste-by-waste strategy to combat global pollution. The researchers highlight how the rapid intensification of industrial and agricultural activities has led to a surge in emerging contaminants, which include persistent pharmaceuticals, pesticides, and microplastics that escape traditional wastewater treatment. By converting everyday waste biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More into a porous material known as biochar, the study illustrates a circular economy model that not only manages solid waste but also creates a platform for cleaning our water and soil. This approach aligns directly with the United Nations Sustainable Development Goals by focusing on the preservation of water resources and the minimization of hazardous chemicals in the environment.

The findings reveal that biochar acts as an exceptional support for immobilizing enzymes, which are natural catalysts capable of breaking down complex pollutants. Specifically, the team found that laccases—a type of oxidoreductase enzyme—can be attached to biochar to significantly enhance their stability and reusability. When these enzymes are free in a solution, they often lose their effectiveness quickly and are difficult to recover. However, once anchored to a waste-derived biochar matrix, they can be used for multiple cycles of treatment. For example, the study notes that laccase immobilized on biochar made from sour cherry stones achieved a 93% removal rate of brilliant green dye in just four hours. Similarly, mushroom residue biochar helped degrade nearly 91% of bisphenol A, a common endocrine disruptor, while maintaining over 65% of its activity after eight uses.

One of the most striking results discussed in the manuscript involves the remediation of soil contaminated with microplastics. By immobilizing a specific plastic-eating enzyme onto biochar produced from pine sawdust, researchers observed a 29.6% reduction in the weight of microplastics within a soil microcosm. Beyond just removing the plastic, the application of this biochar-enzyme complex actually improved the soil environment by modulating nutrient cycles, specifically enhancing phosphorus uptake and nitrogen fixationNitrogen is a crucial nutrient for plant growth, but plants can’t directly absorb it from the air. Nitrogen fixation is a process where certain bacteria convert atmospheric nitrogen into a form that plants can use. Biochar can provide a home for these nitrogen-fixing bacteria, enhancing More. This suggests that the technology does more than just clean; it helps restore the health of the ecosystems it treats. The ability of biochar to adsorb pollutants on its own, combined with the catalytic power of the attached enzymes, creates a synergistic effect that is far more powerful than using either component in isolation.

The economic analysis included in the review indicates that this technology is becoming increasingly viable for large-scale use. With the global biochar market projected to reach 6.3 billion dollars by 2033, the shift toward industrial-scale production is already beginning. In early 2025, commercial partnerships in Canada and the United States were announced to launch plants that will simultaneously destroy persistent chemicals in biosolids while producing useful energy and biochar. The researchers emphasize that the cost of these systems is highly dependent on the initial waste material, meaning that using low-value agricultural scraps like rice husks or corn stover can drive down the price of environmental protection.

Despite these successes, the authors identify several areas for future improvement to ensure this technology reaches its full potential. They call for more studies that simulate real-life ecosystems rather than controlled laboratory settings, as well as the development of advanced molecular models to better predict how different types of biochar will react with specific pollutants. The ultimate goal is to move these discoveries from the university laboratory to commercial water treatment plants and agricultural fields. By fostering collaborations between academic researchers and industrial leaders, the waste-by-waste approach can become a cornerstone of global sustainability efforts, turning the world’s growing piles of trash into a primary defense against environmental contamination.

Source: Machado, C. M. B., de Mello, A. F. M., Bittencourt, G. A., Ramos-Neyra, L. C., Jo, G. S. C., Soccol, C. R., & Vandenberghe, L. P. S. (2026). Biochar production from waste biomass applied in enzyme immobilization for removal of emerging contaminants in an approach of treating waste-by-waste – a literature review. Sustainability Science and Technology, in press.