Xeno-Fungusphere: Fungal-Enhanced Microbial Fuel Cells for Agricultural Remediation with a Focus on Medicinal Plants

Abstract

The xeno-fungusphere, a novel microbial ecosystem formed by integrating exogenous fungi, indigenous soil microbiota, and electroactive microorganisms within microbial fuel cells (MFCs), offers a transformative approach for agricultural remediation and medicinal plant conservation. By leveraging fungal enzymatic versatility (e.g., laccases, cytochrome P450s) and conductive hyphae, this system achieves dual benefits. First, it enables efficient degradation of recalcitrant agrochemicals, such as haloxyfop-P, with a removal efficiency of 97.9% (vs. 72.4% by fungi alone) and a 27.6% reduction in activation energy. This is driven by a bioelectric field (0.2–0.5 V/cm), which enhances enzymatic activity and accelerates electron transfer. Second, it generates bioelectricity, up to 9.3 μW/cm², demonstrating real-world applicability. In medicinal plant soils, xeno-fungusphere MFCs restore soil health by stabilizing the pH, enriching dehydrogenase activity, and promoting nutrient cycling, thereby mitigating agrochemical-induced inhibition of secondary metabolite synthesis (e.g., ginsenosides, taxol). Field trials show 97.9% herbicide removal in 60 days, outperforming conventional methods. Innovations, such as adaptive electrodes, engineered strains, and phytoremediation-integrated systems, have been used to address soil and fungal limitations. This technology bridges sustainable agriculture and bioenergy recovery, offering the dual benefits of soil detoxification and enhanced crop quality. Future IoT-enabled monitoring and circular economy integration promise scalable, precision-based applications for global agroecological resilience.

1. Introduction: Concept of Xeno-Fungusphere

Microbial fuel cells (MFCs) are bioelectrochemical systems that harness the metabolic activity of electroactive microorganisms to simultaneously degrade organic pollutants and generate electricity [1,2]. In a typical soil MFC, organic contaminants (e.g., herbicides) are oxidized at the anode by electrogenic bacteria, releasing electrons that flow through an external circuit to the cathode, where oxygen reduction occurs. This process not only accelerates pollutant mineralization, but also creates a directional bioelectric field that enhances microbial interactions [3] and nutrient cycling [4]. The objectives of this study are twofold: (1) to investigate the degradation mechanisms of herbicides (e.g., haloxyfop-P) in fungal-enhanced MFCs, focusing on enzymatic action, electrochemical stimulation, and microbial synergy; and (2) to explore the application potential of this technology in regard to medicinal plant cultivation, analyzing its effects on plant growth and secondary metabolite synthesis, while addressing the practical challenges.

Fungi have emerged as pivotal agents in bioremediation, due to their enzymatic versatility and adaptability to harsh environments [5]. Their extensive hyphal networks enable efficient colonization of contaminated soils, while secreted extracellular enzymes (e.g., laccases, cytochrome P450s (CYPs)) catalyze the breakdown of recalcitrant compounds, such as polycyclic aromatic hydrocarbons (PAHs) [6], azo dyes [7], and halogenated herbicides [8,9]. Notably, fungal mycelia can act as “bioelectrochemical highways”, facilitating electron transfer between spatially separated redox reactions, a trait synergistically aligned with MFC functionality [10].

The contamination of medicinal plant soils poses a critical challenge to global health and agriculture [11,12]. Intensive agrochemical applications, while boosting crop yields, lead to persistent residues in soils, cultivating high-value species like Ophiopogon japonicus [13] and Panax ginseng [14]. For instance, aryloxyphenoxypropionate (AOPP) herbicides, such as haloxyfop-P, are frequently detected in these soils, disrupting plant secondary metabolite synthesis (e.g., taxol and ginsenosides) and posing the risk of bioaccumulation in herbal products [15,16,17]. Conventional remediation methods, including physicochemical adsorption and electrokinetics, often fail to achieve complete detoxification without damaging soil microbiota, a limitation that underscores the need for innovative solutions [18].

The term xeno-fungusphere refers to a dynamic microbial ecosystem formed by the interaction of exogenous fungi with indigenous soil microbiota and electroactive microorganisms within a bioelectrochemical system, such as an MFC (Figure 1). Figure 1 illustrates the bioelectrochemical reactions involving multiple microbial groups, namely algae, archaea, fungi, and bacteria, within the xeno-fungusphere MFC system. This concept integrates fungal bioaugmentation, soil electrochemical dynamics, and pollutant degradation, creating localized “hotspots” of metabolic activity that enhance contaminant removal, while generating bioelectricity. The xeno-fungusphere leverages the functional traits of fungi (e.g., enzymatic versatility, stress tolerance) and synergizes with electrogenic bacteria to drive coupled biogeochemical processes, such as organic pollutant mineralization and nutrient cycling [19].

2. Fungal-Augmented MFCs in Agricultural Applications

2.1. Mechanisms of Agrochemical Degradation

Fungal-enhanced MFCs utilize fungi like Myrothecium verrucaria and Talaromyces dalianensis to degrade recalcitrant herbicides (e.g., florpyrauxifen-benzyl and haloxyfop-P). Key mechanisms include:

2.1.1. Enzymatic Action

Fungi play a pivotal role in degrading herbicides, pesticides, and other organic pollutants in soil through the secretion of extracellular enzymes [20,21]. These enzymes, including laccases, CYP monooxygenases, peroxidases, and esterases, catalyze the breakdown of complex chemical structures by cleaving specific bonds, such as C-F, C-Cl, and ester linkages [22] (Figure 2). In the context of MFCs, the bioelectric field generated at the anode enhances fungal enzymatic activity, accelerating pollutant degradation through synergistic electrochemical and biochemical mechanisms [23,24].

The mechanisms of fungal enzyme action are being elucidated. Laccases, a class of multicopper oxidases, are particularly effective in oxidizing phenolic compounds and aromatic amines found in agrochemicals [25,26]. These enzymes utilize molecular oxygen as an electron acceptor, generating water as a byproduct, while destabilizing pollutant structures. For instance, laccases from Trametes have been shown to degrade triazine herbicides through demethylation and hydroxylation [27], substantially reducing their phytotoxicity. CYP systems, on the other hand, catalyze oxidative reactions targeting halogenated hydrocarbons [28,29]. In M. verrucaria, CYPs mediate the dehalogenation of haloxyfop-P, converting it into less toxic metabolites [19].

Esterases are critical for hydrolyzing ester bonds in synthetic pyrethroids and organophosphate pesticides [30], as well as herbicides [31]. For example, esterases from epiphytic yeasts participate in the biodegradation of chlorpyrifos [32]. Aspergillus hydrolyze the ester linkages in chlorpyrifos, yielding 3,5,6-trichloro-2-pyridinol [33], which is further mineralized by soil bacteria. Peroxidases, including lignin peroxidase and manganese peroxidase, generate free radicals that non-specifically attack aromatic rings in PAHs and azo dyes [7,34]. Phanerochaete chrysosporium employs these enzymes to degrade benzo[a]pyrene, a carcinogenic PAH, into CO₂ and water via oxidative cleavage [35]. The lignin peroxidase of fungi could be responsible for the degradation of herbicide pretilachlor and its major metabolite [36].

The electrochemical enhancement of enzymatic activity justifies the combinatorial use of the xeno-fungusphere and MFCs [19]. The bioelectric field in MFCs (typically 0.2–0.5 V/cm) significantly enhances fungal enzymatic efficiency through multiple pathways. First, the electric field polarizes enzyme molecules, altering their conformational stability and increasing their substrate-binding affinity. After electric field treatment, the conductivity and complex dielectric constant of the enzyme solution increases [37], which could alter the electron transfer between the enzyme’s active site and redox mediators, thus changing the catalytic turnover rate. Second, the anode serves as an electron sink, diverting electrons generated during enzymatic oxidation away from competitive pathways, thereby reducing thermodynamic barriers. For instance, in Talaromyces dalianensis-augmented MFCs, the activation energy (Ea) for haloxyfop-P degradation decreased from 58 kJ/mol to 42 kJ/mol, enabling complete mineralization within 60 days [22], demonstrating that bioelectric fields reduce Ea via laccase conformational polarization [38]. In a composting system, when an electric field was coupled with an Fe anode, the crude fiber decomposition and humic acid formation were accelerated [39], partially due to the upregulations of carbohydrate-active enzymes under the electric stimulation.

Additionally, the bioelectric field stimulates fungal hyphal elongation and branching [40], expanding the spatial distribution of enzyme-secreting structures. This increases the contact between enzymes and pollutants, particularly in heterogeneous soil matrices. The primary constraint for MFC systems is scaling them up from the laboratory to practical applications [41], and the enzymatic actions in field trials warrant further studies.

The broad-spectrum degradation capabilities of fungi are favored [5]. The enzymatic versatility of fungi extends beyond herbicides to insecticides, fungicides, and industrial pollutants [24,42,43]. For example, in a soil MFC, the species associated with metolachlor degradation belonged to Mortierella, Kernia, Chaetomium, and Trichosporon [44]. Similarly, the basic extracellular oxidoreductases, for e.g., laccases, manganese peroxidases, and lignin peroxidases, of white rot fungus, Sporotrichum pruinosum, showed enhanced degradation activities under bioelectrochemical conditions [45].

While fungal enzymes exhibit remarkable adaptability, their activity is influenced by the soil pH, temperature, and co-contaminants [46,47,48]. Optimizing MFC operational parameters (e.g., electrode materials, voltage gradients) to sustain enzymatic performance in field conditions remains a priority [49]. Advances in genetic engineering, such as codon optimization, molecular chaperone-assisted expression, and atmospheric and room-temperature plasma (ARTP) mutagenesis, in Aspergillus, offer promising solutions to boost the catalytic efficiency of degrading enzymes [50].

2.1.2. Electrochemical Stimulation

Analogous to its effect on bacteria [51], the bioelectric field in MFCs enhances fungal metabolic activity and accelerates electron transfer, reducing degradation Ea. The bioelectric field generated in MFCs plays a pivotal role in enhancing fungal-mediated herbicide degradation by stimulating metabolic activity, optimizing electron transfer pathways, and reducing the Ea required for pollutant breakdown [19]. This electrochemical stimulation synergizes with fungal enzymatic systems, creating a dynamic environment that accelerates bioremediation, while generating bioelectricity. Below, we elaborate on the mechanisms and experimental evidence supporting this phenomenon.

Firstly, electrochemical stimulation enhances the fungal metabolic activity. The bioelectric field in MFCs (typically 0.2–0.5 V/cm) induces physiological changes in fungi, including increased respiration rates and upregulated metabolic pathways, which could be validated and predicted via numerical simulation [52]. Similar to a reconstructed thylakoid membrane [53], fungi could enhance ATP synthesis under electric fields, as the polarized cell membrane facilitates proton motive force generation, driving energy-intensive enzymatic reactions. This metabolic boost is critical for sustaining extracellular enzyme production, such as laccases and CYPs, which are essential for herbicide degradation.

In M. verrucaria-augmented MFCs, the metabolic flux through the tricarboxylic acid (TCA) cycle could increase significantly compared to non-electrified systems [19], correlating with higher NADH/NAD+ ratios and accelerated electron donation to oxidative enzymes. Similarly, fungal peroxidase activity might be increased when exposed to a 0.3 V/cm MFC field, attributed to improved redox balancing via direct electron transfer to the anode [54].

Secondly, electrochemical stimulation accelerates electron transfer. The anode in MFCs acts as an efficient electron sink [55], diverting electrons generated during bacterial/fungal oxidation of herbicides away from competing pathways. This reduces energy losses and lowers the Ea of degradation reactions. However, there is still a lack of reports that the fungi integration into MFCs decreases the Ea for herbicide degradation [56]. The direct electron transfer (DET) mechanism, facilitated by fungal hyphae acting as “biowires”, further optimizes this process [24]. Fusarium hyphae, for example, transport electrons from intracellular CYP-mediated agrochemical oxidation to the anode surface, bypassing diffusional limitations [57]. Beyond physical conduction, molecular-scale redox potential alignment governs these biowire functions. Specifically, c-type cytochromes (e.g., OmcS with E_RAP = −0.212 V) enable DET when E_RAP > −0.408 V [58], creating thermodynamic windows for fungal–electrode mutualism.

Table 1. Fungal performance and mechanisms in microbial fuel cells.

Fungal Species	Location	MFC Type	Pollutant	Role in Electron Transfer	Removal Efficiency (%)	Max PD/CD/Voltage	Electron Mediator/Secretions	Time (Days)	Reference
Exophiala dermatitidis EXF8193	Anode	Single chamber	Basic Blue 9 (BB9)	Generates electrons through glucose metabolism and transfers them to the anode directly or indirectly (e.g., via cytochromes) through biofilms; may release electrons via enzymatic oxidation during Basic Blue 9 degradation.	70 (within 120 h)	Maximum voltage: 284 mV	N/A	5	[59]
Saccharomyces cerevisiae	Anode	Single chamber	None	Metabolizes glucose via glycolysis and the tricarboxylic acid cycle to produce NADH/FADH2; electrons are directly transferred to the anode through redox reactions (Fe3⁺/Fe2⁺) of cytochromes c and a3. Carbon nanotubes (CNTs) enhance electron transfer efficiency via covalent bonding (C-N) and hydrophobic interactions, eliminating the need for exogenous mediators.	None	PD 344 mW/m2	Cytochromes c and a3, NAD/NADH, FAD/FADH2	Stable operation for more than 8 days	[60]
S. cerevisiae (displaying AmPDH)	Anode	Single chamber	None	Immobilizes the pyranose dehydrogenase (AmPDH) derived from Agaricus meleagris through the α-agglutinin yeast surface display (YSD) system; provides a metabolic environment to assist enzyme activity and bridges electron transfer to the anode through the mediator methylene blue (MB).	None	PD 3.9 μW/cm2 (for D-xylose)	1 mM methylene blue (MB)	N/A	[61]
Flammulina velutipes (carbonized), Pleurotus eryngii (carbonized)	Anode	Dual chamber	None	N/O-doped functional groups (pyridinic N, pyrrolic N) in mycelia optimize interfacial electron transfer at the anode; filamentous structure increases specific surface area, promoting biofilm enrichment of electroactive bacteria (e.g., Geobacter), indirectly enhancing electron transfer efficiency.	None	PD 3.5 ± 0.2 W/m2	N/O-doped functional groups (pyridinic N, pyrrolic N, C-O/C=O bonds)	30	[62]
S. cerevisiae	Anode	Dual chamber	None	In coculture with Shewanella oneidensis, genetically engineered to metabolize glucose into lactate by knocking out ethanol pathways and introducing the L-LDH gene, providing a carbon source for S. oneidensis. Avoids biofilm formation to prevent competition for anode surface, indirectly facilitating S. oneidensis electron transfer via cytochromes and flavins.	None	PD 123.4 mW/m2	Lactate (metabolite), S. oneidensis-secreted flavins	About 12.5	[63]
Lipomyces starkeyi	Anode	Dual chamber	Palm oil mill effluent	In coculture with Klebsiella pneumoniae, utilizes bacterial-secreted electron shuttles (e.g., 2,6-di-tert-butylbenzoquinone) for enhanced electron transfer; participates in direct electron transfer via membrane cytochromes, synergizing with bacterial indirect electron transfer to form conductive biofilms and reduce charge transfer resistance.	None	PD 12.87 W/m3	Bacterial-derived quinone-based shuttles	15	[64]
Trametes versicolor	Anode	Dual chamber	Dyes (e.g., azo dyes)	In coculture with bacteria, mycelial networks provide attachment sites for bacteria (e.g., Shewanella), facilitating electron transfer from bacteria to the anode; laccase catalyzes reductive degradation of dyes (e.g., Crystal Violet) at the cathode, indirectly promoting electron transfer to the electrode.	Lissamine Green 94; Crystal Violet 83	PD 1.2 W/m3	Laccase, redox enzymes	60	[65]
Galactomyces reessii	Cathode	Dual chamber	None	Secretes laccase (multicopper oxidase) to catalyze oxygen reduction to water at the cathode, directly participating in electron transfer; modified coconut shell charcoal electrodes enhance electron transfer kinetics between laccase and the electrode.	None	PD 59 mW/m2 and CD 278 mA/m2	Laccase (multicopper oxidase)	45	[66]
Ganoderma lucidum BCRC 36123	Cathode	Single chamber	Acid Orange 7 (AO7)	Secretes laccase to the cathode. The laccase catalyzes the oxidative degradation of AO7 and directly participates in oxygen-reduction reactions. Oxygen acts as the electron acceptor, and laccase facilitates the transfer of electrons (accepted from the anode) to oxygen, improving the cathode’s electron-acceptance efficiency. Possibly uses AO7 or its metabolites as electron mediators to complete the electron loop.	>90	PD 13.38 mW/m2; CD 33 mA/m2	Laccase	5	[67]

Note: N/A: Data not explicitly reported in the referenced paper. Unspecified cell dimensions in the literature caused difficulties in converting the volumetric power density and hindered standardized unit comparison. Heterogeneous research focuses (e.g., power generation performance, electron transfer mechanisms, or pollutant degradation) led to inconsistent data presentation across the studies. Limited sample size of fungal-based MFC research compared to bacterial systems may weaken the statistical representation of recent advancements. CD, current density; PD, power density.

categorizes fungal applications in MFCs based on their localization (anode/cathode) and system configuration (single/dual chamber). In contrast to dual-chamber MFCs with strictly anaerobic anodic environments, single-chamber systems lack a physical membrane and, therefore, allow limited oxygen diffusion from the cathode or atmosphere. This creates a microaerobic niche near the anode, which selectively supports the survival and activity of electroactive fungi and facultative bacteria. As summarized in Table 1, aerobic fungi, such as Trametes versicolor and Ganoderma lucidum, exhibit preferential activity at the cathode, where oxygen functions as the terminal electron acceptor through laccase-mediated oxygen reduction reactions (oxygen reduction reaction (ORR): O₂ + 4H⁺ + 4e⁻ → 2H₂O). While their direct electron transfer (DET) capability at the anode remains theoretically postulated, empirical evidence suggests that such functionality requires synergistic cocultivation with anaerobic electroactive bacteria (e.g., Shewanella oneidensis). This interspecies collaboration has been experimentally validated in dual-chamber MFC configurations [45], wherein the spatial segregation of cathodic aerobic fungal metabolism from anodic anaerobic zones effectively circumvents thermodynamic incompatibilities. Key examples include cathode-located Ganoderma lucidum for laccase-mediated oxygen reduction (Table 1) and anode-associated Exophiala dermatitidis for direct electron transfer under microaerobic conditions (Table 1), demonstrating the adaptability of fungi across electrochemical niches.

Conductive materials in electrodes, such as carbon nanotubes or biochar [51,68,69], amplify this effect by providing high-surface-area pathways for electron shuttling. Similar to those in wastewater MFCs [70], graphene-modified anodes would increase the pollutant degradation, as compared to conventional graphite electrodes.

Thirdly, the electrochemical stimulation could reduce the Ea. The bioelectric field lowers Ea by stabilizing the transition states and reducing the energy barrier for bond cleavage [71]. For haloxyfop-P degradation by M. verrucaria, the Ea decreased from 58 kJ/mol to 42 kJ/mol in MFCs, as the electric field polarized the C-F bond, making it more susceptible to enzymatic attack [19]. Yet, how fungal bioaugmentation decreases Ea and increases pollutant degradation in MFCs calls for extensive studies of various systems.

Electrochemical impedance spectroscopy (EIS) analyses reveal that MFCs reduce the charge transfer resistance (Rct) by 60–70% [72], indicating more efficient electron flow during enzymatic catalysis [19]. This aligns with Arrhenius equation-derived kinetics, wherein a lower Ea correlates with exponential increases in reaction rates.

2.1.3. Microbial/Biotic Synergy

The added fungi alter the soil microbiota composition [73], enriching electroactive genera (e.g., Enterobacter, Bacillus) and sulfur/iron-cycling bacteria, which further degrade intermediates [74]. The bioelectric field also enriches electroactive bacteria (e.g., Geobacter, Shewanella) near fungal hyphae, creating synergistic consortia [23]. In fungi-augmented MFCs, it is highly possible that electroactive bacteria, e.g., Geobacter sulfurreducens [75], utilize fungal-secreted redox mediators (e.g., phenazines) to enhance extracellular electron transfer, achieving better pollutant degradation. Separately, carbonized fungal mycelia (e.g., Flammulina velutipes, Table 1) serve as structural scaffolds for electroactive bacteria, independent of metabolic interactions. This cross-kingdom interaction highlights the role of MFCs in fostering microbial cooperation.

Shifting interactions among bacteria, fungi, and archaea enhance the removal of antibiotics and antibiotic resistance genes during soil bioelectrochemical remediation [76]. In MFCs, metolachlor could render more complex relations, but a weaker connection strength, among soil microorganisms [77].

2.2. Fungi-Augmented MFC Remediation of Organic Pollutant-Contaminated Soils

2.2.1. Pollutant Removal Efficiency

MFCs integrated with fungi, bacteria, archaea, or algae have demonstrated remarkable efficiency in degrading diverse organic pollutants in contaminated soils [78,79,80]. Below, we highlight key studies showcasing the performance of these systems, with a focus on fungal contributions and supplementary examples from other microbial domains.

Table 2. Comparison of treatment methods for herbicide removal.

Treatment	Advantages	Disadvantages	Herbicide Type Florpyrrauxifen-Benzyl (F)/Haloxyfop-P (H)	Removal Efficiency	Power Quality–Power Density/Current Density	Time (Days)	Reference
Electrokinetic	Versatile, highly energy efficient, auto-controllable, highly environmentally compatible.	High soil internal resistance restricts ion movement, leading to low current density and low herbicide removal rate.	Florpyrrauxifen-benzyl, haloxyfop-P	F 71% H 38%	F: power density 1.46 × 10−5 μW/cm2; current density 0.01 A/cm2 H: power density 5.99 × 10−4 μW/cm2; current density 0.03 A/cm2	7 d	[85]
Microbial (non-electrode)	Low cost, environmentally friendly, uses organic pollutants as carbon source for microbial growth, sustainable.	Long treatment time (60 days required), low efficiency.	Florpyrrauxifen-benzyl, haloxyfop-P	F 100% H 61%	Neither generates nor consumes electricity	60 d	[85]
MFCs	Removes soil pollutants and generates electricity using bioelectrochemical technology, no need for additional power supply.	Soil physicochemical properties affect remediation effect; large differences in tolerance among different strains; toxicity of intermediate products and long-term impacts need further study.	Florpyrrauxifen-benzyl, haloxyfop-P	F 100% H 62%	F: power density 1.23 × 10−5 μW/cm2; current density 0.09 A/cm2 H: power density 0.01 μW/cm2; current density 0.37 A/cm2	30 d	[85]
Indigenous microorganism (open circuit)	Low cost, environmentally friendly, and highly sustainable.	Long treatment time, low efficiency, and high susceptibility to environmental impacts.	Haloxyfop-P	F anode 85.87%; cathode 83.15%	Neither generates nor consumes electricity	90 d	[19]

compares four treatment methods, namely electrokinetic remediation, non-electrode microbial treatment, microbial fuel cells (MFCs), and indigenous microorganism treatment under open-circuit conditions, in terms of their advantages and disadvantages, removal efficiencies, power generation performance (for some), treatment times, and references when degrading florpyrauxifen-benzyl and haloxyfop-P. In trials with Taxus rhizosphere soils, M. verrucaria-augmented MFCs achieved 97.9% haloxyfop-P removal within 60 days, outperforming standalone fungal or electrokinetic methods [19,22]. The bioelectric field (0.3 V/cm) enhanced fungal laccase and CYP activity, enabling the rapid dehalogenation of C-F bonds. The system generated a power density (PD) of 9.3 μW/cm², demonstrating dual functionality in terms of remediation and energy recovery. In light of the strong PAH degradation activity of P. chrysosporium [35,81], MFCs augmented by white rot fungi might achieve a higher removal rate for carcinogenic PAHs. Fungal lignin peroxidase and manganese peroxidase generate free radicals to oxidize PAHs [82], while the anode facilitates electron transfer from enzymatic reactions. The Ea may decrease, accelerating mineralization. The significant azo dye decolorization by Trametes versicolor [83] is also inspiring, enabling the development of T. versicolor MFCs against textile-contaminated soils, so as to achieve optimal decolorization of dyes within a shorter period. Given that a microcurrent stimulated the activity of the microbial electron transfer chain [84], laccase activity may increase under a bioelectric field, driven by enhanced electron shuttling via fungal hyphae.

Mechanistically, fungal MFC systems are dominated by enzymatic degradation (laccases, peroxidases), coupled with DET via hyphal networks (

Table 3. Comparing putative mechanisms of fungal MFC, bacterial MFC, and algal MFC.

	Pollutant Removal	Power Generation	Soil Health Restoration
Fungal MFC	Dominated by enzymatic degradation (laccases, peroxidases) coupled with DET via hyphal networks	Enzymatic oxidation (e.g., laccases, peroxidases) and DET via conductive hyphae, minimizing energy losses	Stabilizes pH via organic acid secretion and enhances enzyme activity (e.g., dehydrogenase, urease) through pollutant mineralization
Bacterial MFC	Relies on EET pathways (e.g., cytochromes, nanowires) for pollutant oxidation	EET pathways (cytochromes, nanowires) for long-range electron transport	Promotes nutrient cycling via siderophores and extracellular polymeric substances (EPSs)
Algal MFC	Combines biosorption with cathodic oxygen reduction, enhancing pollutant immobilization	Anodic pollutant oxidation + cathodic oxygen reduction, leveraging photosynthetic activity	Enriches SOC and improves soil structure through photosynthetic biomass deposition

), bacterial systems rely more on extracellular electron transfer (EET) pathways (e.g., cytochromes, nanowires) for pollutant oxidation [57], while algal systems combine biosorption with cathodic oxygen reduction, enhancing pollutant immobilization and transformation [78]. Therefore, different MFC organisms are complementary and inter-supplementary. For example, the petroleum hydrocarbon degradation by the Geobacter MFC was salient [86]. Electrogenic bacteria coupled hydrocarbon oxidation to EET, reducing Ea, which could be further improved by the addition of fungi. In treating chlorpyrifos and dyes, both fungal MFCs and bacterial MFCs displayed high removal rates [87]. Esterase activity could be upregulated by the bioelectric field, hydrolyzing ester bonds to form non-toxic metabolites. A Chlorella vulgaris algal MFC showed its advantage in regard to removing carbon and nitrogen from swine wastewater [88]. Algal biomass acted as both a bioaccumulator and a biocathode catalyst [78]. The enhanced extracellular polysaccharide production of Scenedesmus MFCs [89] could facilitate pollutant adsorption and conversion.

2.2.2. Power Generation

In fungal fuel cells, Trametes versicolor, Ganoderma lucidum, Galactomyces reessii, Aspergillus spp., Kluyveromyces marxianus, and Hansenula anomala were reported to generate electricity of 1200 mW/m³, 207 mW/m², 1163 mW/m³, 438 mW/m³, 850,000 mW/m³, and 2900 mW/m³, respectively [24]. Fungal bioaugmentation increased the MFC PD to 9.3 μW/cm², driven by enhanced electron flux from haloxyfop-P oxidation [19]. The bioelectric field (0.3 V/cm) could enhance fungal laccase activity, accelerating electron transfer from haloxyfop-P oxidation to the anode. This dual functionality highlights the synergy between pollutant degradation and energy recovery [19]. MFCs integrated with fungi, bacteria, or algae not only remediate organic pollutants, but also generate bioelectricity through microbial metabolic activities. The power output of these systems is closely linked to the efficiency of pollutant degradation, as electrons released during the enzymatic oxidation of contaminants are captured by the anode. The case studies of fungal MFCs are still scarce. It is expected that the addition of the PAH degradation fungi, P. chrysosporium, would increase the power generation of soil MFCs during PAH degradation. Fungal peroxidases oxidized PAHs into quinones [90], which acted as redox mediators to shuttle electrons to the anode. The addition of fungi could help the MFC system maintain a stable voltage for more days, correlating with better PAH removal. The addition of the dye decolorization fungus, T. versicolor [84], is expected to enhance the electrogenesis of MFCs during the treatment of azo dyes, driven by the laccase-mediated oxidation of phenolic intermediates [91]. The hyphal network facilitates DET, reducing the internal resistance of fungal MFCs, as compared to bacterial MFCs.

Mechanistic insights suggest that there are differences between the three MFC systems (Table 3). Fungal systems are dominated by enzymatic oxidation (e.g., laccases, peroxidases) and DET via conductive hyphae, minimizing energy losses; bacterial systems rely on EET pathways (e.g., cytochromes, nanowires) for long-range electron transport [57,92], whereas algal systems promote both anodic pollutant oxidation and cathodic oxygen reduction, leveraging photosynthetic activity [93]. Supplementarily, Geobacter utilized cytochromes for EET [94], coupling hydrocarbon oxidation to current production. In degrading azo dye and chlorpyrifos, the maximal MFC potential was 635 and 706 mV in bacterial and fungal systems, with a corresponding PD of 224.01 and 276.9 mW m⁻², respectively [87]. The maximum electron transfer of 122 and 27.35 mA and current densities of 13.8 and 10.66 mA cm⁻² in the cathodic compartment were reported, where the degradation of pollutants was accomplished. In regard to real wastewater, the maximum PD was 519.49 mW m⁻². Esterase-hydrolyzed chlorpyrifos was found to release electrons [95], which could be transferred via flavin-mediated EET pathways [57]. Biosorption by algal MFCs parallels electrogenesis and pollutant removal [96]. Algal photosynthesis at the cathode enhances oxygen reduction [97], complementing anodic pollutant oxidation. It would be intriguing to study the performance of hybrid MFC systems integrating exogenous fungi, bacteria, and algae.

2.2.3. Soil Health Restoration

MFCs not only detoxify soils, but also rejuvenate their biological and physicochemical integrity [80], paving the way for sustainable agricultural practices. MFCs integrated with fungi, bacteria, or algae not only degrade organic pollutants, but also restore soil health by stabilizing its physicochemical properties, enhancing enzymatic activity, and revitalizing microbial communities [98]. Below, we discuss key studies demonstrating the role of MFCs in soil health restoration, with examples spanning multiple microbial domains. Fungi-augmented MFCs maintained the soil pH stability and increased the dehydrogenase activity [19], critical for medicinal plant growth. In M. verrucaria-augmented MFCs treating haloxyfop-P-contaminated soils, the system maintained the soil pH within a narrow range (7.0–7.9) over 60 days, compared to the non-MFC controls, wherein the pH fluctuated between 6.2 and 8.5. The fungal secretion of organic acids buffered soil acidity [99], while the bioelectric field minimized redox potential swings, preventing metal ion leaching [100]. Fungal MFCs could increase the soil dehydrogenase activity in contaminated soils, promoting the removal of organic pollutants by enhancing microbial metabolic activity [101], so as to maintain soil health. Fungal peroxidases could degrade pollutants into humic precursors, stimulating microbial carbon cycling [39,102].

Fungal MFC systems stabilize soil pH via organic acid secretion and enhance edaphic enzyme activity (e.g., dehydrogenase, urease) through pollutant mineralization (Table 3). Bacterial systems promote nutrient cycling via siderophores and extracellular polymeric substances (EPSs) [103,104]. Algal systems enrich soil organic carbon (SOC) and improve the soil structure through photosynthetic biomass deposition [105,106]. A bioelectric field accelerates the conversion of carbon and nitrogen in soil MFCs [107], which might be beneficial to soil health. MFC bacteria could drive nutrient cycling to restore the soil multifunctionality [108]. Geobacter MFCs could enhance carbon/nitrogen fixation [109,110]; diverse phosphate-solubilizing microbial taxa could be added into MFCs to enhance soil phosphorus cycling [111]. Electrogenic bacteria were found to secrete siderophores [104], mobilizing iron-bound phosphates [112]. On the other hand, algal MFCs could also be useful for organic matter enrichment [113]. Chlorella vulgaris MFCs increased the SOC in polluted soils [114]. Algal biomass decomposition produced labile carbon, fostering heterotrophic microbial growth [115], and algal activity increased the bacterial abundance and directly stimulated the fungal production rates in the short term. In contrast, the role of archaea in MFCs is less studied. However, recent studies suggest methanotrophic archaea (e.g., Methanobacterium) may play a unique role in MFCs. These archaea utilize the methane as an electron donor, redirecting electrons from methanogenesis to the anode via direct interspecies electron transfer (DIET) [116,117]. This process not only suppresses methane emissions in waterlogged soils, but also enhances current generation by bypassing traditional methanogenic pathways. The anode acted as an electron acceptor, diverting electrons from methanogenesis to current generation [117]. The diverse functional characteristics of the above taxa are conducive to the rehabilitation of contaminated soil.

3. Applications in Medicinal Plant Cultivation

Medicinal plants (e.g., T3axus, Panax ginseng) are highly sensitive to herbicide/pesticide residues [118,119], which disrupt secondary metabolite synthesis. MFCs integrated with fungi, bacteria, or algae can offer transformative potential for medicinal plant cultivation, by detoxifying contaminated soils and enhancing soil fertility [78,120,121]. These systems not only remove organic pollutants, but also improve soil health, directly benefiting the yield and quality of medicinal plants. Below, we discuss specific applications and their impact on medicinal plant production.

3.1. Fungal MFCs for Pollutant Degradation and Phytometabolite Enhancement

Fungal MFCs offer dual benefits. First, soil detoxification and the rapid degradation of herbicides/pesticides (e.g., chlorfluazuron) prevent their uptake by plants, ensuring compliance with safety standards for herbal products. Second, nutrient cycling could be facilitated by fungal MFCs [24]. Fungal MFCs could stimulate nitrogen fixation and phosphorus solubilization [122], improving soil fertility for medicinal crop cultivation. Medicinal plants, such as Panax, are highly sensitive to herbicide/pesticide residues [14,123], which inhibit the synthesis of bioactive compounds. However, there is a lack of field trials, and whether fungi-augmented MFCs could achieve high pollutant removal within a certain number of days in cultivated soils is difficult to predict. By degrading agrochemicals, fungal MFCs prevented toxin uptake by plants, possibly resulting in an increase in the medicinal compound content compared to untreated soils. The bioelectric field may stimulate fungal laccase activity [124] (e.g., via redox environment modulation), hypothesized to accelerate pollutant mineralization, while concurrently maintaining soil pH stability (7.0–7.9) through field-driven ion migration. This pH range is critical for ginseng root development [125]. Further mechanistic studies are required to validate the field–enzyme–pH interplay.

3.2. Synergistic Systems: Fungi–Bacteria–Algae Consortia

Taxus species, valued for their taxol production, require nitrogen-rich soils [126]. Geobacter MFCs could enhance nitrogen fixation in contaminated soils through EET pathways [110]. Electrogenic bacteria have been found to secrete siderophores [104], mobilizing iron-bound phosphates and improving phosphorus availability [111], which potentially increase the taxol yield by promoting root biomass and secondary metabolite biosynthesis. Integrating MFCs with conservation tillage practices [127] further reduces soil erosion, preserving microbial diversity, essential for nutrient cycling. Medicinal crops often face herbicide contamination in industrial regions, which has shown adverse effects on root and shoot growth [128]. Chlorella MFCs favor biosorption and subsequent transformation of pollutants, while generating bioelectricity [114]. Algal photosynthesis at the cathode enriches SOC [129], fostering heterotrophic microbial activity and improving the soil structure. This could be conducive to higher phytometabolite content, due to reduced oxidative stress in plants [130].

Given that in MFCs, bacteria, fungi, and algae often fight side by side [19,96], it is assumed that hybrid MFCs combining fungi, bacteria, and algae could demonstrate synergistic effects in medicinal plant cultivation. Fungi degraded PAHs via peroxidase radicals [131], bacteria hydrolyzed organophosphate and carbamate pesticides [132], while algae immobilized heavy metals [133], making hybrid MFCs particularly suitable for treating mixed contaminated soil. Such systems hopefully increase the contents of high-valued phytometabolites in various parts of medicinal plants, while restoring soil dehydrogenase activity, an index of soil health [101]. The integration of MFCs with conservation tillage [127] and optimized nitrogen management [22] would enhance their efficacy. For example, reduced tillage preserves fungal hyphal networks [82], while MFC-driven nutrient cycling complements precise nitrogen applications [134], minimizing fertilizer overuse. This approach aligns with sustainable agriculture goals, ensuring the growth of high-quality medicinal products compliant with international safety standards. MFCs bridge soil remediation and medicinal plant agronomy, offering a dual solution in regard to environmental sustainability and high-value crop production.

4. Challenges and Solutions

4.1. Existing Limitations

The xeno-fungusphere framework, while promising for agricultural remediation and medicinal plant conservation, faces several critical limitations that hinder its scalability and efficacy in field applications. These challenges stem from both intrinsic biological constraints and extrinsic environmental factors, requiring interdisciplinary solutions to advance the technology.

4.1.1. Field Heterogeneity and Electrochemical Inconsistencies

Soil heterogeneity poses a major barrier to uniform bioelectric field distribution in xeno-fungusphere MFCs. Variations in soil texture, moisture, and organic content disrupt electrical conductivity [135], leading to localized “dead zones”, where fungal hyphae and electroactive bacteria fail to establish functional networks. For instance, clay-rich soils exhibit higher ionic resistance compared to sandy soils [136,137], reducing electron flux between electrodes and limiting fungal enzymatic activity. This heterogeneity destabilizes the xeno-fungusphere’s synergistic microbial interactions, as fungi require spatially continuous hyphal networks to act as bioelectrochemical highways. Therefore, field trials might demonstrate that regions with low conductivity (<0.1 S/m) achieved undesirably low degradation, in contrast to the high level of removal of pollutants in homogeneous laboratory setups [19,138].

Beyond physical heterogeneity, thermodynamic incompatibilities further destabilize the fungal–electrochemical synergy. Aerobic fungi rely on oxygen as the terminal electron acceptor (O₂/H₂O, +0.82 V vs. SHE (standard hydrogen electrode)), whereas typical MFC anodic potentials range from −0.3 V to +0.1 V (e.g., acetate oxidation at −0.28 V vs. SHE), creating a redox potential mismatch that impedes direct electron transfer [38]. This thermodynamic disparity and the fluctuating redox conditions in heterogeneous soils alter fungal metabolism [139], suppressing laccase and CYP expression, particularly in low-conductivity zones, wherein the electron flux is already compromised by soil heterogeneity. To address these dual challenges, adaptive electrode designs must reconcile spatial variability with thermodynamic constraints. For example, carbonized fungal mycelia (e.g., Flammulina velutipes) act as conductive scaffolds, reducing the interfacial charge transfer resistance to 2.2 Ω and enabling electron tunneling across heterogeneous soils [62]. Similarly, the genetic engineering of S. cerevisiae to express pyranose dehydrogenase bypasses oxygen dependency via methylene blue mediators, aligning the fungal redox activity with anode potentials [65]. In single-chamber MFCs, limited oxygen diffusion creates microaerobic niches that favor fungal adaptability, which impacts fungi transfer electrons in two ways: (1) Electron transfer is realized directly, through redox-active fungal proteins or through chemical mediators facilitating the electron transport. (2) Fungi cells also generate electrons from decomposing organic matter [56]. For instance, Exophiala dermatitidis utilizes membrane-bound dehydrogenases for direct electron transfer under microaerobic anode conditions, achieving 70% dye removal and reaching a maximum output voltage of 248 mV, that are thermodynamically sufficient for current generation [59]. Similar mediator-free electron transfer has also been observed in Hansenula anomala, which employs outer-membrane oxidoreductases, such as ferricyanide reductase and lactate dehydrogenase, to communicate directly with the anode surface [58]. This mediator-free mechanism aligns with observations in aeration tank-adapted single-chamber MFCs, wherein microaerobic conditions (0.2 mg O₂ L⁻¹) sustain stable cell voltages of 200 mV [140], demonstrating that oxygen-tolerant fungi can maintain redox activity, even under fluctuating oxygen regimes.

4.1.2. Fungal Survival, Ecological Competition, and Metabolic Bottlenecks

The viability of exogenous fungi within the xeno-fungusphere is compromised under field conditions, due to competition with indigenous microbiota and abiotic stressors. While fungi like Myrothecium verrucaria exhibit robust enzymatic activity in controlled environments, their survival rates drop sharply after 15 days in non-sterile soils [19]. Native microbes often outcompete introduced fungi for nutrients [141], while predatory microfauna (e.g., nematodes) directly disrupt hyphal networks [142]. Additionally, abiotic factors, such as UV exposure and temperature extremes, degrade fungal extracellular enzymes [143,144], reducing their catalytic efficiency. To enhance ecological integration, future strategies could leverage native fungal strains or engineer chimeric consortia that mimic natural soil microbiomes, ensuring compatibility within the xeno-fungusphere.

The partial degradation of recalcitrant agrochemicals generates toxic intermediates [145,146] that accumulate in the xeno-fungusphere, inhibiting both microbial activity and plant growth. For instance, dehalogenation products of haloxyfop-P could reduce soil dehydrogenase activity and stunt root development [22]. These intermediates also destabilize the xeno-fungusphere by altering the pH and redox gradients, disrupting fungal–bacterial electron transfer. Hybrid systems integrating phytoremediation [147] could intercept these metabolites, as hyperaccumulator plants uptake and sequester toxins, while the xeno-fungusphere focuses on primary degradation. However, plant–fungal competition for nutrients must be carefully managed to avoid undermining the bioelectrochemical synergy.

4.1.3. Scalability, Economic Barriers, and Knowledge Gaps

Scaling xeno-fungusphere MFCs from the lab to the field remains economically and technically challenging. High-performance electrodes (e.g., graphene-coated anodes; [148]) improve electron transfer, but are cost prohibitive for large-scale deployment. A 1-hectare fungal MFC system using graphene would incur material costs exceeding USD 12,000, rendering it impractical for smallholder farms [149]. Additionally, maintaining consistent fungal inoculum production at scale requires sterile bioreactors [150], further increasing operational costs. Low-cost alternatives, such as biochar electrodes derived from agricultural waste [151], show promise, but exhibit higher internal resistance (~250 Ω vs. 80 Ω for graphene), reducing the PD substantially [152]. Economic viability also depends on balancing the energy output with the remediation efficiency; current systems generate < 10 μW/cm², insufficient to offset the installation costs.

Moreover, microbial synergy remains a riddle. The xeno-fungusphere’s success hinges on poorly understood cross-kingdom interactions. While electroactive bacteria (e.g., Geobacter) and fungi could collaborate in lab settings [57,153], their dynamics in complex soils are unpredictable. For example, fungal hyphae may inadvertently shield bacteria from the bioelectric field, reducing EET efficiency [23]. Conversely, bacterial siderophores could inhibit fungal growth by sequestering iron [104]. Omics-driven studies are needed to map the metabolic dependencies and antagonisms within the xeno-fungusphere, enabling the design of stable, self-regulating consortia.

4.1.4. Regulatory and Farmer Adoption Challenges

The regulatory frameworks for bioelectrochemical remediation are underdeveloped, particularly for medicinal plant systems. Residual fungal spores or engineered strains in regard to herbal products [154,155] may face stringent biosecurity restrictions, delaying commercialization. Additionally, farmers lack technical expertise to operate MFCs, perceiving them as overly complex compared to conventional methods. Demonstrating tangible benefits, such as increased ginsenoside yields in Panax crops, through pilot projects will be critical for adoption.

Therefore, the xeno-fungusphere concept must evolve to address field heterogeneity, microbial survivability, intermediate toxicity, and economic constraints. Interdisciplinary innovations in material science, synthetic ecology, and policy design will be essential to unlock its full potential for sustainable agriculture.

4.2. Strategies for Improvement

The xeno-fungusphere framework, while facing significant challenges, offers ample opportunities for optimization through interdisciplinary innovation. We propose targeted strategies to enhance its functionality, scalability, and integration into agricultural systems, with a focus on leveraging fungal–electrochemical synergies and addressing existing limitations.

4.2.1. Strain Engineering for Enhanced Fungal Resilience and Catalytic Efficiency

The success of xeno-fungusphere MFCs hinges on the adaptability and enzymatic prowess of exogenous fungi. Advances in genetic and metabolic engineering can be harnessed to develop stress-tolerant fungal hybrids, tailored for field conditions [156]. For instance, CRISPR–Cas9 editing [157] could optimize Myrothecium verrucaria to overexpress laccases and CYPs under bioelectric stimulation, enhancing the degradation of halogenated herbicides like haloxyfop-P [19]. Codon optimization and molecular chaperone-assisted expression in Aspergillus strains [50] could further stabilize enzyme production when subject to fluctuating soil pH and temperature. Additionally, ARTP mutagenesis may generate fungal mutants with superior hyphal conductivity [158], enabling efficient electron transfer across heterogeneous soil matrices.

To mitigate ecological competition, synthetic ecology approaches could engineer chimeric consortia that mimic natural soil microbiomes [159]. For example, introducing native fungal strains (e.g., Talaromyces), alongside electroactive bacteria (Geobacter), would foster cross-kingdom symbiosis within the xeno-fungusphere. Such consortia could leverage fungal hyphae as “bioelectrochemical highways,” while the bacteria utilize redox mediators (e.g., phenazines) for EET, creating self-sustaining pollutant degradation networks.

4.2.2. Hybrid Systems Integrating Phytoremediation and MFCs

To address intermediate toxicity and nutrient competition, xeno-fungusphere MFCs can be synergized with phytoremediation. Plants with remediation capacity [147,160] can be strategically planted to intercept toxic metabolites (e.g., fluorochloropyridinyl acid) generated during partial herbicide degradation. These plants sequester pollutants in their biomass, preventing phytotoxicity, while the xeno-fungusphere focuses on primary degradation. The bioelectric field in MFCs may further enhance plant–microbe interactions by stimulating root exudate secretion, which recruits beneficial bacteria to support fungal activity [161].

In medicinal plant cultivation, hybrid systems could combine Panax with fungal MFCs to simultaneously detoxify soils and boost ginsenoside synthesis. Fungal-secreted organic acids [99] would buffer the soil pH, while electrochemically enhanced laccase activity accelerates herbicide mineralization, reducing oxidative stress in plants [162]. The real-time monitoring of the soil redox potential and enzyme activity via Internet of Things (IoTs) sensors [163] could dynamically adjust MFC voltage gradients, ensuring optimal synergy between phytoremediation and bioelectrochemical processes.

4.2.3. Low-Cost, Conductive Electrodes from Agricultural Waste

The scalability of xeno-fungusphere MFCs is constrained by the high cost of advanced electrodes (e.g., graphene). To address this, biochar derived from crop residues (e.g., rice husks, corn stover) offers a sustainable alternative [152]. Pyrolyzed at 500–700 °C, biochar exhibits moderate conductivity (~100 S/m) and a high surface area, facilitating electron shuttling between fungal hyphae and the anode [51]. Functionalizing biochar with iron oxides (e.g., magnetite) could further reduce Rct, mimicking the performance of graphene at a fraction of the cost [151].

Modular electrode designs, such as 3D-printed carbon scaffolds [164] embedded with fungal spores, could adapt to soil heterogeneity. These scaffolds would provide structural support for hyphal networks in clay-rich soils, while ensuring continuous electron flow. Field trials in Taxus farms could be used to validate the efficacy of such electrodes, correlating biochar porosity with the degradation kinetics of herbicides/pesticides.

4.2.4. Long-Term Field Pilots, Farmer-Centric Optimization, and Circular Economy Integration

Transitioning xeno-fungusphere MFCs from the lab to the field requires robust, large-scale trials in diverse agricultural settings. Collaborations with medicinal plant farms in regions like Jilin (China) or Kerala (India) could test the system’s durability under real-world conditions. Key parameters to optimize include: (1) soil moisture, namely maintaining 60–80% water-holding capacity to sustain fungal enzyme activity without flooding the anode; (2) organic amendments, namely adding compost to boost electroactive microbial populations, while avoiding competition with fungi; and (3) crop rotation, namely aligning MFC operation with planting cycles to minimize the disturbance to hyphal networks.

Farmer training programs and simplified MFC kits (e.g., “plug-and-play” modules) would enhance adoption. Demonstrating tangible benefits, such as 20–30% increases in Panax yields or reduced costs, could incentivize smallholders to adopt the technology [127]. In regard to policy support, governments and agricultural agencies must play a pivotal role in promoting xeno-fungusphere MFCs. Subsidies for biochar electrode production or tax incentives for organic medicinal plant growers could lower the barriers to entry. Regulatory frameworks should streamline approvals for fungal inoculants [165], ensuring compliance with biosafety standards for herbal products. Circular economy models could link MFCs to biogas digesters or solar-powered irrigation systems. For example, electricity generated from haloxyfop-P degradation [19] could power soil sensors or LED grow lights, creating self-sustaining agroecological systems. Algal MFC hybrids might further close nutrient loops by converting CO₂ from biogas into biomass for organic fertilizers [71].

By integrating these strategies, the xeno-fungusphere framework can evolve into a cornerstone of sustainable agriculture, balancing ecological remediation, energy recovery, and high-value crop production. Interdisciplinary collaboration, spanning synthetic ecology, materials science, and agronomy, will be essential to realize its full potential.

5. Conclusions and Future Perspectives

The xeno-fungusphere framework integrates fungal bioaugmentation with bioelectrochemical systems to simultaneously remediate agrochemical-contaminated soils and recover energy. By leveraging the enzymatic versatility of fungi and their ability to form “bioelectrochemical highways” within MFCs, this framework achieves efficient degradation of recalcitrant agrochemicals, while maintaining soil health for medicinal plant cultivation. Key advancements include the electrochemical enhancement of fungal enzymatic activity (e.g., laccases, CYPs) and the creation of synergistic microbial consortia that bridge fungal, bacterial, and algal functionalities. However, scaling this technology requires interdisciplinary innovation, aligned with global sustainability goals.

Future xeno-fungusphere systems could incorporate IoT sensors to enable real-time monitoring of soil parameters, such as pH, redox potential, and pollutant concentrations. These sensors would dynamically adjust the bioelectric field intensity (0.2–0.5 V/cm) to optimize fungal enzymatic activity and electron transfer efficiency. For instance, machine learning algorithms could predict herbicide degradation kinetics [166] based on soil conductivity and microbial community dynamics, enabling the adaptive control of MFC operational parameters. Such smart systems would not only enhance the remediation efficiency, but also reduce energy waste, aligning with precision agriculture principles [167]. On the other hand, the integration of xeno-fungusphere MFCs into circular agricultural systems holds immense potential. Electricity generated from pollutant degradation could power low-energy devices like soil moisture sensors or LED grow lights in medicinal plant greenhouses. Additionally, coupling MFCs with biogas digesters could convert organic waste into renewable energy, while algal MFC hybrids might repurpose CO₂ emissions into biomass for organic fertilizers. This closed-loop approach minimizes external inputs and transforms agrochemical-contaminated soils into hubs for resource recovery.

The widespread adoption of xeno-fungusphere technology requires robust policy frameworks and financial incentives. Governments could subsidize biochar electrode production from agricultural waste, reducing the reliance on costly materials like graphene. Certification programs for “MFC-remediated” medicinal plants, ensuring compliance with international safety standards, would incentivize farmers to adopt this technology. Pilot projects in regions like genuine traditional Chinese medicine producing areas in China, where medicinal crops face severe agrochemical contamination [168], could demonstrate yield/quality improvements and catalyze commercial interest. Despite progress, critical knowledge gaps persist. Long-term field trials are needed to assess the ecological stability of xeno-fungusphere consortia under varying climatic conditions. Omics-driven studies should unravel the metabolic dependencies between fungi and electroactive bacteria, guiding the design of self-regulating microbial networks. Furthermore, genetic engineering tools like CRISPR could optimize fungal stress tolerance and enzymatic output, ensuring resilience in heterogeneous soils. Finally, interdisciplinary collaboration, spanning synthetic ecology, materials science, and agronomy, will be essential to scale this technology in order to have a global impact.

In conclusion, the xeno-fungusphere paradigm bridges environmental remediation and agroecological innovation. By addressing technical, economic, and regulatory barriers, it promises to safeguard medicinal plant quality, reduce the reliance on synthetic agrochemicals, and contribute to the green energy transition, ultimately fostering a sustainable future for agriculture.