Search Results (14)

The textile industry generates dye-containing wastewater characterized by intense coloration, high salinity, elevated oxygen demand, and recalcitrant pollutants. Although conventional treatment technologies can remove color and reduce organic load, decolorization alone does not guarantee detoxification because toxic transformation products may persist or be generated during incomplete degradation. This review emphasizes the synergistic interaction between oxidative and reductive enzymes and microorganisms as a promising strategy for promoting extensive pollutant transformation and potentially enhancing mineralization. Particular attention is given to the complementary roles of laccases (LAC), azoreductases (AZOR), ligninolytic peroxidases, bacteria, fungi, and microbial consortia in sequential degradation pathways that can improve detoxification efficiency. Mechanisms including azo bond cleavage, aromatic amine transformation, and subsequent microbial degradation are discussed to demonstrate how integrated systems can overcome the limitations of enzyme- or microorganism-based treatments alone and may facilitate complete pollutant removal under appropriate conditions. The review also explores biomass-derived biocatalysts produced through solid-state fermentation of agro-industrial residues, demonstrating opportunities to integrate wastewater remediation with biomass valorization and circular bioeconomy principles. Finally, operational challenges, toxicity assessment, reactor design, enzyme immobilization, scale-up, and techno-economic considerations are discussed, and future research priorities are identified to support the development of sustainable and industrially applicable enzymatic–microbial detoxification technologies. Full article

Co-contamination with dibenzofuran (DBF) and cadmium (Cd(II)) poses a major challenge in environmental remediation. While Burkholderia sp. can degrade polycyclic aromatic hydrocarbons and tolerate heavy metals, the coordinated mechanism governing DBF degradation under high Cd(II) stress remains elusive. Here, we characterize Burkholderia sp. FM-2, which optimally degrades 600 mg/L DBF at pH 6.0 and 25 °C, achieving 91.8% removal within 48 h. FM-2 exhibits exceptional Cd(II) tolerance, with a minimum inhibitory concentration of 2000 mg/L. UPLC-MS/MS confirms DBF degradation via dioxygenase-mediated hydroxylation and sequential enzymatic reactions. Transcriptomics reveals, for the first time, concurrent upregulation of genes encoding RND efflux pumps, ABC transporters, P-type ATPases, and core DBF-degrading enzymes under high Cd(II) stress, enabling the synergistic maintenance of intracellular Cd(II) homeostasis and efficient DBF degradation. Collectively, FM-2 remediates DBF-Cd(II) co-contamination via coordinated transcriptional regulation of degradation and detoxification pathways, offering a promising strain resource and molecular basis for the bioremediation of co-contaminated environments. Full article

Soil biofilms are structured, dynamic microbial consortia embedded within extracellular polymeric substances that regulate microscale physicochemical heterogeneity and drive biogeochemical transformations in soils. Despite increasing interest in biofilm-mediated remediation, current reviews have largely examined microbial ecology, engineered biofilm functions, and predictive modelling independently, limiting systems-level understanding of pollutant fate in complex soils. This review, therefore, proposes a revised conceptual framework integrating biofilm ecology, synthetic biology, and AI-driven predictive modelling to improve mechanistic and predictive understanding of emerging pollutant detoxification. Emerging pollutants, including pharmaceuticals, pesticides, per- and polyfluoroalkyl substances, micro- and nanoplastics, and heavy metals, exhibit persistence, bioaccumulation, and mixture-dependent effects that challenge conventional remediation strategies. Biofilm matrices function as reactive interfaces facilitating adsorption, sequestration, and enzymatic transformation, while steep redox and nutrient gradients support metabolically diverse processes such as cometabolism, syntrophic degradation, and biomineralisation. Increasing evidence indicates that quorum sensing, horizontal gene transfer, and low-abundance microbial taxa contribute significantly to adaptive responses and functional plasticity within biofilms. Advances in high-resolution imaging, spatial multi-omics, and microfluidic platforms have resolved previously inaccessible biofilm architectures and processes; however, integration with machine learning and process-based modelling remains limited, restricting field-scale prediction of pollutant behaviour and remediation outcomes. Synthetic biology enables targeted optimisation of biofilm functions, whereas AI-driven models enhance prediction of contaminant transport, transformation, and detoxification. Soil biofilms function both as sinks and catalytic hotspots, and resolving this duality through a predictive, systems-level framework represents a major advance beyond existing descriptive reviews. Full article

Microcystins (MCs), a group of potent hepatotoxins from cyanobacterial blooms, threaten global water security due to the resistance to conventional treatment processes and multi-organ toxicity to human. This study innovatively proposed a novel sequential process combining UV irradiation with biodegradation by Sphingopyxis sp. m6 for efficient microcystin-LR (MC-LR) removal. Results revealed that sequential UV-C pretreatment followed by Sphingopyxis sp. m6 biodegradation achieved complete degradation of 1 mg/L of MC-LR within 1 h of the biological phase, drastically reducing the treatment time compared to biodegradation alone (5 h). Mechanistic investigation revealed that low-dose UV-C (50 mJ/cm²) pretreatment induced MC-LR photoisomerization consistently with previously reported Adda geometric isomers. These photoisomers, along with residual parent MC-LR, were subsequently mineralized by Sphingopyxis sp. m6. Enzymatic pathway analysis confirmed a dual-pathway degradation, where Mlr enzymes processed both the native toxin and its isomeric forms, leading to a series of linearized peptides and Adda-derived products. Critically, the process achieved efficient detoxification, as confirmed by the restoration of HepG2 cell proliferation and protein phosphatase 2A activity. Moreover, response surface methodology optimized the key parameters (31.49 °C, pH of 7.36, 0.23 mg/L) for the highest degradation efficiency. This work provides an energy- and cost-efficient strategy for MC-LR remediation and elucidates the molecular mechanism of UV-induced photoisomerization facilitating subsequent biodegradation. Full article

Soil co-contamination with heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) represents a widespread and challenging environmental issue that is difficult to address using conventional remediation methods. This review systematically examines the molecular mechanisms by which plant root exudates mediate the remediation of co-contaminated soils through synergistic interactions with rhizosphere microorganisms. We detail how plants dynamically adjust the composition and secretion of root exudates—such as organic acids, amino acids, sugars, and secondary metabolites—in response to combined HM-PAH stress. These exudates play multifaceted roles in remediation, including chelating HMs, enhancing PAH solubility and bioavailability, and acting as chemoattractants and metabolic substrates for rhizosphere microbes. In return, the recruited microbial communities contribute to pollutant detoxification through various mechanisms, such as biosurfactant production, enzymatic degradation, and improved plant nutrient acquisition. This reciprocal interaction forms a synergistic plant-microbe feedback loop that effectively mitigates combined contamination stress. By integrating evidence from diverse plant–soil systems, this review provides a comprehensive mechanistic framework for understanding root exudate-microbe interactions, offering critical insights for developing enhanced phytoremediation strategies to address complex environmental pollution. Full article

Fungal laccases are promising oxidative enzymes for bioremediation applications, particularly in the degradation of synthetic dyes present in industrial effluents. Here, we evaluated the inhibitory effects of sodium chloride (NaCl) and sodium sulfate (Na₂SO₄) on the activity of Trametes versicolor laccase and its ability to decolorize Congo Red (CR), Malachite Green (MG), and Remazol Brilliant Blue R (RBBR). Enzyme assays revealed concentration-dependent inhibition, with IC₅₀ values of 0.22 ± 0.04 M for NaCl and 1.00 ± 0.09 M for Na₂SO₄, indicating stronger inhibition by chloride. Kinetic modeling showed mixed-type inhibition for both salts. Despite this effect, the enzyme maintained significant activity: after 12 h, decolorization efficiencies reached 95 ± 4.0% for MG, 88 ± 3.0% for RBBR, and 75 ± 3.0% for CR, even in the presence of 0.5 M salts. When applied to a mixture of the three dyes, decolorization decreased only slightly in saline medium (94.04 ± 4.0% to 83.43 ± 5.1%). FTIR spectra revealed minor structural changes, but toxicity assays confirmed marked detoxification, with radicle length in lettuce seeds increasing from 20–38 mm (untreated dyes) to 41–48 mm after enzymatic treatment. Fungal growth assays corroborated reduced toxicity of treated dyes. These findings demonstrate that T. versicolor laccase retains functional robustness under ionic stress, supporting its potential application in saline textile wastewater remediation. Full article

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. Full article

Heavy metal pollution from industrial activities and poor waste disposal poses significant environmental and health threats to humans and animals. This calls for sustainable approaches to the cleanup of heavy metals. This review explores metal tolerance mechanisms of bacteria such as the formation of biofilms, efflux systems, and enzymatic detoxification. These mechanisms allow bacteria communities to adapt and survive in contaminated environments. These adaptations are enhanced by mutations in the bacteria genes and by horizontal gene transfers, enabling bacteria species to survive under environmental stress while simultaneously contributing to nutrient cycling and the decomposition of organic matter. This review further explores the symbiotic interactions between bacteria, plants, and animals. These relationships enhance the metal tolerance ability of the different living organisms involved and are also very important in the bioremediation and phytoremediation of heavy metals. Plant growth-promoting rhizobacteria, Rhizobium, and Bacillus species are very important contributors to phytoremediation; they improve heavy metal uptake, improve the growth of roots, and plants resilience to stress. Moreover, this review highlights the importance of genetically engineered bacteria in closed-loop systems for optimized metal recovery. This offers environmentally friendly and sustainable options to the traditional remediation methods. Engineered Cupriavidus metallidurans CH34 and Pseudomonas putida strain 15420352 overexpressing metallothioneins have shown enhanced metal-binding capabilities, which makes them very effective in the treatment of industrial wastewaters and in biosorption applications. The use of engineered bacteria for the cleanup of heavy metals in closed-loop systems promotes the idea of a circular economy by recycling metals, thus reducing environmental waste. Multidisciplinary research that integrates synthetic biology, microbial ecology, and environmental science is very important for the advancement of metal bioremediation technologies. This review’s analysis on bacterial metal tolerance, symbiosis, and bioengineering strategies offers a pathway to effective bioremediation options, for the reclamation of heavy metal-polluted environments while promoting sustainable environmental practices. Full article

Arsenic contamination in sludge and sediment has emerged as a pressing environmental issue with far-reaching implications. This review delves into the multifaceted problem of arsenic contamination, focusing on its complex interactions with microbial resistance genes (MRGs). It explores the key role of microorganisms in the biogeochemical cycling of arsenic, including processes such as reduction, oxidation, methylation, and volatilization. It describes how microorganisms resist arsenic through resistance genes that encode proteins such as efflux pumps, enzymatic detoxification, and intracellular sequestration. Arsenic, a naturally occurring element, can enter sludge and sediment through various natural and anthropogenic pathways, leading to detrimental effects on environmental quality. Understanding the role of microorganisms in arsenic mobilization, transformation, and their ability to resist arsenic toxicity through MRGs is essential for effective mitigation and remediation strategies. This review discusses the sources and distribution of arsenic in sludge and sediment, the intricate mechanisms of microbial arsenic resistance, and the potential implications for environmental management and human health. It also examines current research trends and identifies areas requiring further investigation. By unraveling the interplay between arsenic contamination, microorganisms, and MRGs, this review aims to contribute to a deeper understanding of the issue and guide future research and environmental protection efforts. Full article

The increased presence of cadmium in the environment can lead to its increase in the food chain, particularly due to its accumulation in the consumable parts of plants. For humans, ingesting food containing high levels of Cd is a significant exposure pathway. Being a non-essential and non-metabolized element, it is harmful to microorganisms, animals, plants, and humans, even in minimal concentrations. As a result, there is a need for the remediation of both natural and urban environments. Bioremediation is a sustainable and eco-friendly technique for cleaning up the environment and reducing contamination of living organisms. This review explores the potential of phytoremediation, a bioremediation approach that utilizes plants as agents for decontamination, as a method to restore such areas. Certain plants, particularly macrophytes, are capable of remediating Cd. In response to induced stress, plants activate various tolerance mechanisms, including antioxidant enzyme systems (as peroxidase, catalase, ascorbate peroxidase, superoxide dismutase, and glutathione peroxidase) as well as non-enzymatic pathways (like phytochelatins). However, a thorough understanding of these tolerance mechanisms is essential for optimizing this method, especially for application in aquatic environments. This study will, therefore, review the existing tolerance and detoxification mechanisms for Cd, along with bioremediation strategies. The application of this eco-friendly approach is highly correlated with the three main areas required for sustainability: economic, environmental and social. Full article

Organophosphorus compounds (OPCs), including highly toxic nerve agents and pesticides, have been used widely in agricultural and military applications. However, they have aroused widespread concern because they persistently pollute the environment and threaten human life. Organophosphorus acid anhydrolase (OPAA) is a promising enzyme that can detoxify OPCs. Here, a novel OPAA (OPAA114644) was isolated and characterized from deep-sea sediment (−3104 m). It exhibited excellent alkaline stability, and the loss of activity was less than 20% in the pH range 5.0–9.0, even after being incubated for 30 d at 4 °C. It also exhibited high salt tolerance, and its enzymatic activity increased by approximately fourfold in the presence of 20% NaCl (w/v). Additionally, OPAA114644 exhibited high degradation efficiency for soman, dichlorvos, paraoxon, coumaphos, and chlorpyrifos with a concentration of up to 250 mg/L, with the degradation rate being 100%, 100%, 100%, 80% and 51%, respectively, in 20 min under optimal conditions. Notably, OPAA114644 dissolved in different solutions, such as 20% NaCl, 1 mM SDS, 0.05% soap, 10% methanol, and tap water, could efficiently decontaminate the residual paraoxon on the surfaces of glasses, cotton tissues, and apples. These results indicate that OPAA114644 has excellent potential for the biodegradation and bioremediation of OPCs pollution and represents a real application of OPAA in the decontamination and detoxification of foods and clothes, and in the remediation of sites such as floors. Deep-sea sediment might also be an abundant resource for various functional microorganisms and enzymes. Full article

Increasing attention is more and more directed toward the thermostable Phosphotriesterase-Like-Lactonase (PLL) family of enzymes, for the efficient and reliable decontamination of toxic nerve agents. In the present study, the DNA Staggered Extension Process (StEP) technique was utilized to obtain new variants of PLL enzymes. Divergent homologous genes encoding PLL enzymes were utilized as templates for gene recombination and yielded a new variant of SsoPox from Saccharolobus solfataricus. The new mutant, V82L/C258L/I261F/W263A (4Mut) exhibited catalytic efficiency of 1.6 × 10⁵ M⁻¹ s⁻¹ against paraoxon hydrolysis at 70°C, which is more than 3.5-fold and 42-fold improved in comparison with C258L/I261F/W263A (3Mut) and wild type SsoPox, respectively. 4Mut was also tested with chemical warfare nerve agents including tabun, sarin, soman, cyclosarin and VX. In particular, 4Mut showed about 10-fold enhancement in the hydrolysis of tabun and soman with respect to 3Mut. The crystal structure of 4Mut has been solved at the resolution of 2.8 Å. We propose that, reorganization of dimer conformation that led to increased central groove volume and dimer flexibility could be the major determinant for the improvement in hydrolytic activity in the 4Mut. Full article

Carbon nanomaterials are widely studied and applied nowadays, with annual production increasing. After entering the environment, the complete degradation of these carbon nanomaterials by microorganisms is proposed as an effective approach for detoxification and remediation. In this study, we evaluated the degradation of pristine multiwalled carbon nanotubes (p-MWCNTs) and oxidized multiwalled carbon nanotubes (o-MWCNTs) by the white rot fungus Phanerochaete chrysosporium, which is a powerful decomposer in the carbon cycle and environmental remediation. Both p-MWCNTs and o-MWCNTs were partially oxidized by P. chrysosporium as indicated by the addition of oxygen atoms to the carbon skeleton in the forms of C=O and O–H bonds. The fungal oxidation led to the shortening of MWCNTs, where precipitated o-MWCNTs showed more short tubes. During the transformation, the defects on the tubes became detached from the carbon skeleton, resulting in decreases of the I_D/I_G (intensity of D-band/ intensity of G-band) values in Raman spectra. The transformation mechanism was attributed to the enzymatic degradation by laccase and manganese peroxidase excreted by P. chrysosporium. The results collectively indicated that MWCNTs could be transformed by P. chrysosporium, but complete degradation could not be achieved in a short time period. The implications on the environmental risks of carbon nanomaterials are discussed. Full article

Enzymatic degradation of organic pollutants is a new and promising remediation approach. Peroxidases are one of the most commonly used classes of enzymes to degrade organic pollutants. However, it is generally assumed that all peroxidases behave similarly and produce similar degradation products. In this study, we conducted detailed studies of the degradation of a model aromatic pollutant, Sulforhodamine B dye (SRB dye), using two peroxidases—soybean peroxidase (SBP) and chloroperoxidase (CPO). Our results show that these two related enzymes had different optimum conditions (pH, temperature, H₂O₂ concentration, etc.) for efficiently degrading SRB dye. High-performance liquid chromatography and liquid chromatography –mass spectrometry analyses confirmed that both SBP and CPO transformed the SRB dye into low molecular weight intermediates. While most of the intermediates produced by the two enzymes were the same, the CPO treatment produced at least one different intermediate. Furthermore, toxicological evaluation using lettuce (Lactuca sativa) seeds demonstrated that the SBP-based treatment was able to eliminate the phytotoxicity of SRB dye, but the CPO-based treatment did not. Our results show, for the first time, that while both of these related enzymes can be used to efficiently degrade organic pollutants, they have different optimum reaction conditions and may not be equally efficient in detoxification of organic pollutants. Full article