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Mycoremediation of Persistent Organic Pollutants

Illustration showing fungi degrading Persistent Organic Pollutants using enzymatic systems like laccase, MnP, and LiP in contaminated soil and water environments.
Figure 1: This ultra-realistic digital painting illustrates the role of white-rot fungi and other fungal groups in the degradation of Persistent Organic Pollutants (POPs). It highlights the enzymatic systems involved—laccase, manganese peroxidase (MnP), and lignin peroxidase (LiP)—each participating in the breakdown of complex pollutants. The image captures fungi interacting with soil and water in contaminated environments, performing biosorption, bioaccumulation, and pollutant uptake. The visualization depicts a multi-step mycoremediation process, showcasing how these fungi mitigate environmental contamination through enzymatic transformation of pollutants, offering a sustainable approach to environmental cleanup.

Persistent Organic Pollutants (POPs) encompass a diverse group of hazardous chemical substances, including pesticides (e.g., DDT, lindane), industrial chemicals (e.g., PCBs, dioxins), and unintended byproducts (e.g., polycyclic aromatic hydrocarbons - PAHs). Their defining characteristics—persistence in the environment, bioaccumulation in food chains, toxicity to humans and wildlife, and capacity for long-range environmental transport—make them a significant global concern. Conventional remediation techniques for POP-contaminated sites are often costly, energy-intensive, and can lead to secondary pollution. Mycoremediation, the use of fungi and their metabolic processes to degrade or sequester contaminants, has emerged as a highly promising, eco-friendly, and cost-effective alternative. Fungi, particularly white-rot fungi, possess robust enzymatic systems capable of breaking down the complex and recalcitrant structures of many POPs.

This article delves into the current understanding and cutting-edge advancements in the mycoremediation of POPs. It explores the diverse enzymatic and non-enzymatic mechanisms employed by fungi, highlights key fungal genera demonstrating significant degradative potential, discusses innovative strategies to enhance remediation efficacy, and critically examines the existing challenges and underexplored opportunities. By synthesizing current knowledge and proposing novel hypotheses, this review aims to illuminate the path towards harnessing fungal capabilities for effectively tackling the pervasive issue of POP pollution.

Fungal Arsenal: Mechanisms of POP Degradation

Fungi employ a multifaceted strategy to attack and neutralize POPs, primarily driven by their powerful extracellular ligninolytic enzyme systems. These enzymes, evolved to degrade the complex polymer lignin in wood, are non-specific and can fortuitously degrade a wide array of structurally similar pollutants, including POPs. The key players are laccases (Lac), manganese peroxidases (MnP), and lignin peroxidases (LiP). Laccases are multi-copper oxidases that catalyze the oxidation of phenolic compounds and anilines, often using mediators to expand their substrate range to non-phenolic POPs. MnP utilizes Mn(II) as a substrate, oxidizing it to Mn(III), which then acts as a diffusible oxidizer of phenolic and non-phenolic compounds. LiP, with its high redox potential, can directly oxidize non-phenolic aromatic rings, initiating the degradation cascade (Agrawal et al., 2018; Pundir et al., 2024; Egbewale et al., 2024).

Beyond extracellular enzymes, the intracellular cytochrome P450 monooxygenase (CYP450) system plays a crucial role, particularly in the initial transformation of POPs. These enzymes introduce oxygen atoms into the pollutant molecule, increasing its polarity and susceptibility to further degradation by other enzymes (Dey et al., 2024). Fungal biomass itself also contributes through biosorption and bioaccumulation, where POPs are adsorbed onto the fungal cell wall or taken up into the cell, effectively sequestering them from the environment (Upadhyay et al., 2024). Furthermore, fungi can degrade POPs via co-metabolism, where the pollutant is broken down incidentally during the metabolism of a primary growth substrate, a common scenario when fungi are grown on lignocellulosic materials (Hultberg & Golovko, 2024; Omoni et al., 2024).

Illustration of fungal degradation of persistent organic pollutants using enzymatic and biological processes.
Figure 2: This conceptual illustration displays fungi employing a suite of mechanisms to degrade persistent organic pollutants (POPs). Fungal enzymes such as laccases (Lac), manganese peroxidases (MnP), lignin peroxidases (LiP), and cytochrome P450 monooxygenase (CYP450) play central roles. The diagram highlights these enzymes’ functions in breaking down pollutants via oxidative reactions. Additionally, the depiction includes processes of biosorption, bioaccumulation, and co-metabolism within fungal cells, showing how fungi integrate multiple strategies for pollutant degradation. The backdrop of a wooded environment suggests the natural context in which ligninolytic activity typically occurs.

Key Fungal Players in POP Mycoremediation

White-rot fungi (WRF), belonging to the Basidiomycota, are the most extensively studied and effective group for POP mycoremediation due to their robust ligninolytic enzyme machinery. Genera such as Pleurotus (oyster mushrooms), Trametes (turkey tail), Phanerochaete, and Ganoderma have demonstrated significant capabilities in degrading a wide spectrum of POPs, including PAHs, pesticides, polychlorinated biphenyls (PCBs), and synthetic dyes which often share structural similarities with POPs (Agrawal et al., 2018; Ibrahim et al., 2024; Hultberg & Golovko, 2024). For instance, Ganoderma lucidum has been shown to efficiently degrade phenanthrene and pyrene, producing significant amounts of laccase, LiP, and MnP (Agrawal et al., 2018).

While WRF are champions, other fungal groups also contribute significantly. Species from genera like Aspergillus, Penicillium, and Fusarium (Ascomycota and Deuteromycota) possess diverse metabolic pathways and have been found effective against specific POPs, including certain pesticides and industrial dyes (Ghanaim et al., 2024; Dey et al., 2024; Magnoli et al., 2023; Serag et al., 2025). Aspergillus flavus, for example, efficiently degrades various azo dyes through enzymatic action (Ghanaim et al., 2024). Endophytic fungi, which live symbiotically within plant tissues, represent an emerging frontier. Their intimate association with plants could facilitate in-planta degradation of POPs or enhance phytoremediation processes by degrading pollutants taken up by the host plant, potentially offering a synergistic approach to soil and water cleanup (Bhardwaj, 2025; Obi et al., 2024). This highlights a novel integrative strategy where plant-fungal partnerships could be engineered for more effective pollutant removal.

Comparison chart of fungal groups and their abilities in degrading POPs.
Figure 3: This comparison chart visually represents the capabilities of various fungal groups, including White-rot fungi, Aspergillus, Penicillium, Fusarium, and endophytic fungi, in the degradation of Persistent Organic Pollutants (POPs) such as PAHs, pesticides, dyes, and PCBs. The chart highlights key genera, their enzymatic tools like laccases and peroxidases, their substrate range, and unique features such as endophyte-plant interactions. A modern, infographic-style layout with a color-coded scheme enhances understanding of each group's specialization and diversity in handling environmental pollutants.

Innovations and Strategies for Enhanced Mycoremediation

Maximizing the efficiency of mycoremediation requires innovative approaches. Bioaugmentation, the introduction of specific, highly efficient fungal strains or consortia to a contaminated site, and biostimulation, the addition of nutrients or growth substrates (e.g., lignocellulosic waste) to stimulate native or introduced fungal activity, are foundational strategies (Matilda & Samuel, 2024; Omoni et al., 2024). Immobilization techniques, where fungal cells or their enzymes are encapsulated or attached to a support matrix (e.g., hydrogels, biochar), can enhance enzyme stability, facilitate biomass recovery, and improve operational control in bioreactor systems (Upadhyay et al., 2024; Zhang et al., 2025). Such immobilized systems could be particularly effective for continuous treatment of industrial effluents containing POPs.

The advent of genetic engineering and 'omics' technologies (genomics, transcriptomics, proteomics, metabolomics) offers powerful tools to tailor fungi for superior POP degradation. These approaches can be used to identify novel degradative enzymes, understand regulatory networks, and engineer strains for enhanced enzyme production, broader substrate specificity, or increased tolerance to toxic pollutants and harsh environmental conditions (Dey et al., 2024; Kumar et al., 2025; Wong et al., 2025). For instance, proteomics has been used to unveil cellular responses and key enzymes in Aspergillus fumigatus during lindane degradation (Dey et al., 2024). Furthermore, developing fungal consortia, potentially with bacteria or microalgae, can lead to synergistic degradation of complex POP mixtures, as different organisms may tackle different steps in the degradation pathway or detoxify inhibitory intermediates (Rathour et al., 2024). The integration of mycoremediation with other technologies, such as biochar amendment (which can sorb POPs and act as a fungal habitat) or nanomaterials (as catalyst supports or enzyme carriers), also shows promise for enhancing overall remediation outcomes (Zhang et al., 2023; Dabas, 2025).

Conceptual illustration of a modern mycoremediation system showing bioaugmentation, biostimulation, immobilization of fungal enzymes, and the use of engineered fungi.
Figure 4: This illustration showcases an advanced mycoremediation system designed to efficiently degrade persistent organic pollutants (POPs). The image integrates multiple innovative strategies: bioaugmentation and biostimulation enhance fungal activity, while fungal enzymes and cells are immobilized for continuous operation. Engineered and consortium-based fungi are depicted, leveraging genetic engineering and omics-based approaches to maximize degradation capabilities. Biochar and nanomaterials are visualized to illustrate their role in increasing pollutant removal efficiency. The cutaway side-view presents these components in a synergistic eco-technological environment, bridging industrial applications with environmental sustainability.

Bridging Gaps: Challenges, Novel Hypotheses, and Untapped Potential

Despite significant progress, several challenges hinder the widespread application of mycoremediation for POPs. The bioavailability of POPs in soil and sediment is a major limitation, as these hydrophobic compounds tend to sorb strongly to organic matter and clay particles, making them less accessible to fungal enzymes. The toxicity of high concentrations of POPs or their degradation intermediates can inhibit fungal growth and enzymatic activity. Competition with native soil microflora and the complexities of scaling up lab-scale successes to effective and predictable field-scale applications, including inoculum production, delivery, and long-term survival and activity, remain significant hurdles (Pundir et al., 2024; Magnoli et al., 2023). A critical, often overlooked aspect is the potential for incomplete degradation, leading to the formation of new metabolites that may be as toxic, or even more toxic, than the parent POP. Comprehensive toxicological assessment of treated matrices is therefore essential (Upadhyay et al., 2024).

A largely underexplored area is the potential of extremophilic fungi. Fungi isolated from extreme environments (e.g., high salinity, extreme pH, high temperatures, or pollutant-rich sites) possess unique enzymatic and physiological adaptations that could make them inherently more robust and efficient for degrading recalcitrant POPs in challenging industrial waste streams or co-contaminated sites (Farouk et al., 2025; Chia et al., 2024). It is hypothesized that extremophilic fungi, with their specialized enzymes and stress-response mechanisms, could offer superior degradation rates and resilience when dealing with highly persistent POPs or complex pollutant mixtures that inhibit conventional mesophilic fungi. Another significant untapped potential lies in the mycoremediation of 'forever chemicals' like per- and polyfluoroalkyl substances (PFAS). While current research is limited, the broad specificity and oxidative power of fungal ligninolytic enzymes, particularly laccases and peroxidases, suggest they could be candidates for breaking the highly stable C-F bonds in PFAS, a critical research need identified in recent reviews (Pundir et al., 2024). This points to a nascent but potentially high-impact research direction.

Comparative illustration of current challenges and future directions in mycoremediation of POPs, showing pollutants and fungi in hostile environments.
Figure 5: This detailed scientific illustration contrasts the current challenges in mycoremediation of persistent organic pollutants (POPs) with future innovations. On the left, the difficulties are highlighted: pollutants are shown as being hard to access and detoxify, compounded by issues like toxic metabolite formation and difficulties in scaling up mycoremediation processes. On the right, future directions are illuminated, featuring extremophilic fungi thriving in harsh environments thanks to specialized enzymes. The illustration uses vibrant contrasts to depict how these future solutions could potentially tackle persistent pollutants like PFAS, symbolized by fungal enzymes intricately breaking down complex molecules, providing a visual metaphor for the breakthroughs in this field.

Conclusion

Mycoremediation presents a compelling, environmentally sound, and potentially low-cost strategy for addressing the global challenge of POP contamination. The diverse enzymatic machinery of fungi, especially white-rot fungi, offers a natural solution for transforming these persistent and toxic chemicals into less harmful substances. Key implications include the detoxification of contaminated soils, sediments, and industrial effluents, contributing to environmental restoration and human health protection. However, realizing the full potential of mycoremediation requires concerted research efforts.

Future directions should focus on: (1) Discovering and characterizing novel fungal strains and enzymes with superior POP-degrading capabilities, particularly from unique or extreme environments. (2) Leveraging genetic and metabolic engineering, guided by 'omics' data, to develop hyper-efficient fungal biocatalysts. (3) Designing and optimizing robust bioreactor systems and in-situ application strategies for diverse environmental matrices. (4) Deepening our understanding of fungal ecology, pollutant bioavailability, and degradation pathways in complex, real-world contaminated environments. (5) Rigorous and standardized assessment of metabolite formation and toxicity to ensure complete detoxification. An open problem remains the effective degradation of complex mixtures of POPs, often found in contaminated sites, which may require multi-species consortia or integrated treatment trains. A provocative question for the future is: Can we engineer synergistic fungal-based systems that not only remediate POPs but also valorize the breakdown products or the fungal biomass itself into valuable bioproducts (e.g., biofuels, platform chemicals, or bio-based materials like mycelium composites), thereby transforming a pollution problem into a resource opportunity and fostering a circular bioeconomy approach to waste management? (Wattanavichean et al., 2025; Omoni et al., 2024; Nascimento Deschamps et al., 2024). Successful translation of mycoremediation technologies from the lab to the field will ultimately depend on interdisciplinary collaboration, addressing scalability, and ensuring regulatory and public acceptance.

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