Biochar-driven rhizoremediation of soil contaminated with organic pollutants: engineered solutions, microbiome enrichment, and bioeconomic benefits for ecosystem restoration

Abstract Soil contamination with organic pollutants is a growing environmental concern, with the FAO reporting that 80% of agricultural soils contain such residues. Industrial chemical production has doubled to 2.3 billion tonnes and is projected to increase by 85% by 2030, exacerbating the issue. Key pollutants include pesticides, pharmaceuticals, antimicrobials, and plastic residues, contributing to a 15–20% loss in agricultural productivity. In this context, rhizosphere-mediated remediation has gained significant attention for its potential to degrade organic contaminants. Rhizoremediation, when integrated with biochar application, not only enhances contaminant degradation but also supports plant and microbial growth due to biochar’s nutritive properties and its role in improving contaminant bioavailability. This review explores the synergistic interactions between plant–microbe systems and the role of biochar in accelerating the degradation of major organic contaminants, including crude oil, pesticides, polycyclic aromatic hydrocarbons (PAHs), antibiotics, and organic dyes, aligning with circular bioeconomy principles. Additionally, meta-omics approaches such as metagenomics, transcriptomics, and metabolomics provide insights into active microbial communities involved in the rhizoremediation-biochar process. The efficiency of pollutant sorption and desorption is influenced by biochar’s chemical structure, composition, porosity, surface area, pH, elemental ratios, and functional groups. Therefore, this review also highlights the potential of engineered biochar for enhanced rhizoremediation while addressing challenges associated with its application, emphasizing the need for optimization strategies to mitigate any negative impacts. Furthermore, the exponential growth of the biochar market, valued at USD 2.05 billion in 2023, presents a promising opportunity for both global economic expansion and ecosystem restoration, underscoring the significance of biochar in sustainable environmental management.