Fungal bioremediation of diuron-contaminated waters: Evaluation of its degradation and the effect of amendable factors on its removal in a trickle-bed reactor under non-sterile conditions

Construction of a comprehensive functional screening system for Phanerochaete sordida YK-624 cytochrome P450s: Identification of catalytic enzymes for emerging contaminant degradation

The white-rot fungus Phanerochaete sordida YK-624 is capable of degrading various emerging contaminants (ECs), with cytochrome P450 (CYP) enzymes playing crucial catalytic roles in the degradation process. In this study, we first identified 214 putative CYPs in P. sordida YK-624 (PsCYPs), of which 208 PsCYPs were classified into 31 CYP families, and 6 PsCYPs remained unclassified. To construct a comprehensive functional screening system for identifying PsCYPs involved in EC degradation, a heterologous co-expression system was established using Saccharomyces cerevisiae. The heterologous expressing yeasts were then used to evaluate the degradation of 7-ethoxycoumarin, a natural compound commonly used to assess CYP activity. Several expressing yeasts catalyzed the hydroxylation and O-deethylation of 7-ethoxycoumarin, confirming that these yeasts expressed active forms of PsCYPs. Subsequent degradation experiments were conducted on ECs such as carbazole, acetamiprid (ACE), bisphenol A (BPA), and loxoprofen (LOX). Metabolite analyses using LC/MS, GC/MS and NMR revealed that the PsCYPs catalyzed the hydroxylation of carbazole, BPA, and LOX, as well as the N-dealkylation of ACE. These findings not only provide strong evidence supporting our previous finding regarding degradation research mediated by P. sordida YK-624 mycelia, but also offer valuable insights for future bioprospecting of fungal CYPs in the bioremediation of EC.

Construction of P450 scaffold biocatalysts for the biodegradation of five chloroanilines

Chloroanilines represent a class of persistent and highly toxic environmental pollutants, posing significant challenges for green remediation strategies. While P450BM3 monooxygenases are renowned for their ability to catalyze the monooxidation of inert C-H bonds, costly NAD(P)H and complex electron transport systems required for P450BM3 catalysis limit their practical applications. This study pioneers the development of innovative artificial biocatalysts by strategically engineering the active site of P450BM3. Specifically, the substitution of the highly conserved threonine 268 with aspartic acid effectively induces peroxygenase activity, allowing for enhanced catalytic efficiency. Remarkably, the engineered P450BM3 mutants achieved degradation rates of 98.38-99.18 % for five chloroanilines (4-chloroaniline, 2-chloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, and 3,5-dichloroaniline) in just 10-15 min, all without the need for NAD(P)H or dual-functional small molecules. Comprehensive degradation mechanism analysis via UPLC-MS corroborated the remarkable performance of these biocatalysts. This research not only demonstrates a novel approach for engineering P450 monooxygenases to exhibit peroxygenase activity but also significantly broadens their potential applications in synthetic chemistry and synthetic biology, paving the way for greener and more sustainable remediation technologies.

Environmental bioremediation of pharmaceutical residues: microbial processes and technological innovations: a review

The ubiquitous presence of pharmaceuticals and personal care products (PPCPs) in the environment has become a significant concern due to their persistence, bioaccumulation potential in biota, and diverse implications for human health and wildlife. This review provides an overview of the current state-of-the-art in environmental bioremediation techniques for reducing pharmaceutical residues, with a special emphasis on microbial physiological aspects. Numerous microorganisms, including algae, bacteria or fungi, can biodegrade various pharmaceutical compounds such as antibiotics, analgesics and beta-blockers. Some microorganisms are capable of transferring electrons within the cell, and this feature can be harnessed using Bio Electrochemical Systems (BES) to potentiate the degradation of pharmaceuticals present in wastewater. Moreover, researchers are evaluating the genetic modification of microbial strains to improve their degradation capacity and expand list of target compounds. This includes also discuss how environment changes, such as fluctuations in temperature or pH, may affect bioremediation efficiency. Furthermore, the presence of pharmaceuticals in the environment is emphasised as a major public health issue because it increases the chance for antibiotic-resistant bacteria emerging. This review combines existing information and outlines needed research areas for improving bioremediation technologies in the future.

Analysis of Gene Regulatory Network and Transcription Factors in Different Tissues of the Stropharia rugosoannulata Fruiting Body

Stropharia rugosoannulata is a mushroom that is rich in nutrients and has a pleasant flavor. Its cultivation area is expanding rapidly due to its simplicity and diversity. However, the developmental mechanism of the fruiting body, which constitutes the edible portion of S. rugosoannulata, remains to be elucidated. To address this knowledge gap, we conducted a comprehensive study. Our approach entailed the observation of sections through the fruiting body of S. rugosoannulata and the sequencing of the transcriptomes of various fruiting body tissues. The results demonstrated significant variations in the structure of the pileipellis, pileus, gill, veil, stipe, and trama of S. rugosoannulata. The predominant metabolic pathways included the amino acid metabolism of the pileus, sugar metabolism of the stipe, tryptophan metabolism, and wax production of the pileipellis, the DNA pathway of the gill, amino sugar metabolism of the veil, and the nitrogen metabolism of the trama. The promoter cis-element analysis revealed the roles of light response, methyl jasmonate, oxygen, and temperature on the differentiation of the veil, trama, and pileipellis, respectively. In summary, the present findings offer a molecular mechanism for the development of the fruiting body and provide directions for the enhancement of cultivation techniques of S. rugosoannulata.

Ganoderma lucidum Immobilized on Wood Demonstrates High Persistence During the Removal of OPFRs in a Trickle-Bed Bioreactor

Emerging pollutants such as organophosphate flame retardants (OPFRs) pose a critical threat to environmental and human health, while conventional wastewater treatments often fail to remove them. This study addresses this issue by evaluating the bioremediation potential of white-rot fungi for the removal of two OPFRs: tris(2-chloroethyl) phosphate (TCEP) and tributyl phosphate (TBP). Three fungal species-Ganoderma lucidum, Trametes versicolor, and Phanerochaete velutina-were screened for their degradation capabilities. Among these, G. lucidum and T. versicolor demonstrated removal efficiencies exceeding 99% for TBP, while removal rates for TCEP were significantly lower, with a maximum of 30%. The exploration of the enzyme role showed that cytochrome P450 is involved in the degradation while the extracellular laccase is not involved. Continuous batch experiments were performed using a trickle-bed reactor (TBR) operating under non-sterile conditions, a setting that closely resembles real-world wastewater treatment environments. G. lucidum was immobilized on oak wood chips, and the removal efficiencies were measured to be 85.3% and 54.8% for TBP and TCEP, respectively, over 10 cycles. Microbial community analysis showed that G. lucidum remained the dominant species in the reactor. These findings demonstrate the efficacy of fungal-based trickle-bed bioreactors, offering a sustainable and efficient alternative for addressing environmental pollution caused by highly recalcitrant pollutants.

Metagenomic approaches in bioremediation of environmental pollutants

Metagenomics has emerged as a pivotal tool in bioremediation, providing a deeper understanding of the structure and function of the microbial communities involved in pollutant degradation. By circumventing the limitations of traditional culture-based methods, metagenomics enables comprehensive analysis of microbial ecosystems and facilitates the identification of new genes and metabolic pathways that are critical for bioremediation. Advanced sequencing technologies combined with computational and bioinformatics approaches have greatly enhanced our ability to detect sources of pollution and monitor dynamic changes in microbial communities during the bioremediation process. These tools enable the precise identification of key microbial players and their functional roles, and provide a deeper understanding of complex biodegradation networks. The integration of artificial intelligence (AI) with machine learning algorithms has accelerated the process of discovery of novel genes associated with bioremediation and has optimized metabolic pathway prediction. Novel strategies, including sequencing techniques and AI-assisted analysis, have the potential to revolutionize bioremediation by enabling the development of highly efficient, targeted, and sustainable remediation strategies for various contaminated environments. However, the complexity of microbial interactions, data interpretation, and high cost of these advanced technologies remain challenging. Future research should focus on improving computational tools, reducing costs, and integrating multidisciplinary approaches to overcome these limitations.

Degradation of Isopyrazam in Soil: Kinetics, Microbial Mechanism, and Ecotoxicity of the Transformation Product

The degradation of isopyrazam in soils was investigated through kinetics, microbial contributions, and transformation products (TPs). Then the acute toxicity of isopyrazam and its TP to Chlorella pyrenoidosa was explored. The half-lives of isopyrazam in cinnamon soil, red soil, and black soil were 82.2, 141.7, and 120.3 days, respectively. A strain (Bacillus sp. A01) isolated from cinnamon soil could degrade 72.9% of isopyrazam at 10 mg/L after 6 days in a Luria-Bertani medium. Six TPs were observed with Bacillus sp. A01, and three of them were found in soil as well. Through the inhibition of cytochrome P450 enzymes, the production of oxidized isopyrazam was blocked. Microbial mediated hydroxylation, epoxidation, and dehydration were the main degradation pathways of isopyrazam. The acute toxicity results showed that the EC50 of 3-(difluoromethyl)-N-(9-(2-hydroxypropan-2-yl)-1,2,3,4-tetrahydro-1,4-methanonaphthalen-6-yl)-1-methyl-1H-pyrazole-4-carboxamide to Chlorella pyrenoidosa was 40 times higher than that of the parent. This work provides new insights for understanding the degradation behavior of isopyrazam in soil.

A review on the management of rinse wastewater in the agricultural sector

Pesticides have become indispensable compounds to sustain global food production. However, a series of sustainable agricultural practices must be ensured to minimize health and environmental risks, such as eco-friendly cultivation techniques, the transition to biopesticides, appropriate hygiene measures, etc. Hygiene measures should include the management of rinse wastewater (RWW) produced when cleaning agricultural equipment and machinery contaminated with pesticides (among other pollutants), such as sprayers or containers. Although some technical guidelines encourage the reuse of RWW in agricultural fields, in many cases the application of specialized treatments is a more environmentally friendly option. Solar photocatalysis was found to be the most widely studied physical-chemical method, especially in regions with intense solar radiation, generally using catalysts such as TiO2, Na2S2O8, and H2O2, operating for relatively short treatment periods (usually from 10 min to 9 h) and requiring accumulated radiation levels typically ranging from 3000 to 10000 kJ m-2. Biological treatments seem to be particularly suitable for this application. Among them, biobed is a well-established and robust technology for the treatment of pesticide-concentrated water in some countries, with operating periods that typically range from 1 to 24 months, and with temperatures preferably close to 20 °C; but further research is required for its implementation in other regions and/or conditions. Solar photocatalysis and biobeds are the only two systems that have been tested in full-scale treatments. Alternatively, fungal bioremediation using white rot fungi has shown excellent efficiencies in the degradation of pesticides from agricultural wastewater. However, greater efforts should be invested in gathering more information to consolidate these technologies and expand their use in the agricultural sector.

Mechanistic insights into the effects of diuron exposure on Alexandrium pacificum

Diuron (N-(3,4-dichlorophenyl)-N,N‑dimethylurea, DCMU), a ureic herbicide, is extensively used in agriculture to boost crop productivity; however, its extensive application culminates in notable environmental pollution, especially in aquatic habitats. Therefore, the present study investigated the effect of diuron on the dinoflagellate Alexandrium pacificum, which is known to induce harmful algal blooms (HAB), and its potential to biodegrade DCMU. Following a four-day DCMU exposure, our results revealed that A. pacificum proficiently assimilated DCMU at concentrations of 0.05 mg/L and 0.1 mg/L in seawater, attaining a complete reduction (100 % efficiency) after 96 h for both concentrations. Moreover, evaluations of paralytic shellfish toxins content indicated that cells subjected to higher DCMU concentrations (0.1 mg/L) exhibited reductions of 73.4 %, 86.7 %, and 75 % in GTX1, GTX4, and NEO, respectively. Exposure to DCMU led to a notable decrease in A. pacificum's photosynthetic efficacy, accompanied by increased levels of reactive oxygen species (ROS) and suppressed cell growth, with a growth inhibition rate of 41.1 % at 72 h. Proteomic investigations pinpointed the diminished expression levels of specific proteins like SxtV and SxtW, linked to paralytic shellfish toxins (PSTs) synthesis, as well as key proteins associated with Photosystem II, namely PsbA, PsbD, PsbO, and PsbU. Conversely, proteins central to the cysteine biosynthesis pathways exhibited enhanced expression. In summary, our results preliminarily resolved the molecular mechanisms underlying the response of A. pacificum to DCMU and revealed that DCMU affected the synthesis of PSTs. Meanwhile, our data suggested that A. pacificum has great potential in scavenging DCMU.

Recent advances in fungal xenobiotic metabolism: enzymes and applications

Fungi have been extensively studied for their capacity to biotransform a wide range of natural and xenobiotic compounds. This versatility is a reflection of the broad substrate specificity of fungal enzymes such as laccases, peroxidases and cytochromes P450, which are involved in these reactions. This review gives an account of recent advances in the understanding of fungal metabolism of drugs and pollutants such as dyes, agrochemicals and per- and poly-fluorinated alkyl substances (PFAS), and describes the key enzymes involved in xenobiotic biotransformation. The potential of fungi and their enzymes in the bioremediation of polluted environments and in the biocatalytic production of important compounds is also discussed.

Untargeted metabolomic analysis to explore the impact of soil amendments in a non-conventional wastewater treatment

As non-conventional wastewater treatment, vegetation filters make the most of the natural attenuation processes that occur in soil to remove contaminants, while providing several environmental benefits. However, this practice may introduce contaminants of emerging concern (CECs) and their transformation products (TPs) into the environment. A potential improvement to the system was tested using column experiments containing soil (S) and soil amended with woodchips (SW) or biochar (SB) irrigated with synthetic wastewater that included 11 selected CECs. This study evaluated: i) known CECs attenuation and ii) unknown metabolites formation. Known CECs attenuation was assessed by total mass balance by considering both water and soil media. An untargeted metabolomic strategy was developed to assess the formation of unknown metabolites and to identify them in water samples. The results indicated that SB enhanced CECs attenuation and led to the formation of fewer metabolites. Sorption and biodegradation processes were favored by the bigger surface area of particles in SB column, especially for compounds with negative charges. Incorporating woodchips into soil shortened retention times in the column, which reduced attenuation phenomena and resulted in the formation of significantly more metabolites. Incomplete biodegradation reactions, fostered by shorter retention times in SW column could mainly explain these results.

Filamentous fungi for sustainable remediation of pharmaceutical compounds, heavy metal and oil hydrocarbons

This review presents a comprehensive summary of the latest research in the field of bioremediation with filamentous fungi. The main focus is on the issue of recent progress in remediation of pharmaceutical compounds, heavy metal treatment and oil hydrocarbons mycoremediation that are usually insufficiently represented in other reviews. It encompasses a variety of cellular mechanisms involved in bioremediation used by filamentous fungi, including bio-adsorption, bio-surfactant production, bio-mineralization, bio-precipitation, as well as extracellular and intracellular enzymatic processes. Processes for wastewater treatment accomplished through physical, biological, and chemical processes are briefly described. The species diversity of filamentous fungi used in pollutant removal, including widely studied species of Aspergillus, Penicillium, Fusarium, Verticillium, Phanerochaete and other species of Basidiomycota and Zygomycota are summarized. The removal efficiency of filamentous fungi and time of elimination of a wide variety of pollutant compounds and their easy handling make them excellent tools for the bioremediation of emerging contaminants. Various types of beneficial byproducts made by filamentous fungi, such as raw material for feed and food production, chitosan, ethanol, lignocellulolytic enzymes, organic acids, as well as nanoparticles, are discussed. Finally, challenges faced, future prospects, and how innovative technologies can be used to further exploit and enhance the abilities of fungi in wastewater remediation, are mentioned.

Biotransformation of chloramphenicol by white-rot-fungi Trametes versicolor under cadmium stress

The recalcitrant chloramphenicol (CAP) combined with heavy metals cadmium (Cd) commonly co-existed in the environment, posing threat to environment health. The capacity of Trametes versicolor to remove/biodegrade CAP in air-pulse fluidized-bed reactor was evaluated, even under Cd stress. T. versicolor could remove 44 % CAP of 5 mg/L in 15 days, even 51 % CAP under 1 mg/L Cd stress. Sustained Cd stress inhibited CAP biodegradation and Cd removal in a 5-batches of a 5-days cycle sequential batch reactor. Nine transformation products and two novel pathways were proposed, with initial multi-step transformation reaction into CP2 and allylic alcohol, respectively. Furthermore, the main mechanism of Cd removal by T. versicolor was extracellular surface bioadsorption and intracellular accumulation. This study filled the gap of the mechanism of simultaneous CAP removal/biodegradation and Cd removal by white-rot fungi T. versicolor, which offer a theoretical basis for future application of biological removal of CAP containing wastewater.

Fungal treatment of agricultural washing wastewater: Comparison between two operational strategies

Agricultural washing wastewater (AWW) is an important source of pesticides that, given its intrinsic characteristics, has a high potential to be treated by fungal bioremediation using white rot fungi. In the present study, two AWW treatment strategies were compared: a fluidized-bed reactor (FBR) with T. versicolor pellets and a rotating drum bioreactor (RDB) with T. versicolor immobilized on wood. The RDB effluent showed better results in all studied parameters compared to those of the FBR, including pesticide removal (87%), toxicity, laccase activity, COD, absorbance and microbial communities. Additionally, the fungal assemblage showed that T. versicolor was successfully immobilized in the RDB, which triggered a major shift in the initial community. Afterwards, solid by-products were treated in a fungal biopile-like system reaching high biodegradation rates. Therefore, this study validates the fungal RDB as a viable alternative for AWW treatment, opening up the possibility of a further in-situ and full-scale application.

Pesticide contamination in agro-ecosystems: toxicity, impacts, and bio-based management strategies

Continuous rise in application of pesticides in the agro-ecosystems in order to ensure food supply to the ever-growing population is of greater concern to the human health and the environment. Once entered into the agro-ecosystem, the fate and transport of pesticides is determined largely by the nature of pesticides and the soil attributes, in addition to the soil-inhabiting microbes, fauna, and flora. Changes in the soil microbiological actions, soil properties, and enzymatic activities resulting from pesticide applications are the important factors substantially affecting the soil productivity. Disturbances in the microbial community composition may lead to the considerable perturbations in cycling of major nutrients, metals, and subsequent uptake by plants. Indiscriminate applications are linked with the accumulation of pesticides in plant-based foods, feeds, and animal products. Furthermore, rapid increase in the application of pesticides having long half-life has also been reported to contaminate the nearby aquatic environments and accumulation in the plants, animals, and microbes surviving there. To circumvent the negative consequences of pesticide application, multitude of techniques falling in physical, chemical, and biological categories are presented by different investigators. In the present study, important findings pertaining to the pesticide contamination in cultivated agricultural soils; toxicity on soil microbes, plants, invertebrates, and vertebrates; effects on soil characteristics; and alleviation of toxicity by bio-based management approaches have been thoroughly reviewed. With the help of bibliometric analysis, thematic evolution and research trends on the bioremediation of pesticides in the agro-ecosystems have also been highlighted.

Fungal bioremediation of agricultural wastewater in a long-term treatment: biomass stabilization by immobilization strategy

Fungal bioremediation emerges as an effective technology for pesticide treatment, but its successful implementation depends on overcoming the problem of microbial contamination. In this regard, fungal immobilization on wood seems to be a promising strategy, but there are two main drawbacks: the predominant removal of pesticides by sorption and fungal detachment. In this study, agricultural wastewater with pesticides was treated by Trametes versicolor immobilized on wood chips in a rotary drum bioreactor (RDB) for 225 days, achieving fungal consolidation and high pesticide biodegradation through two main improvements: the use of a more favorable substrate and the modification of operating conditions. Fungal community dynamic was assessed by denaturing gradient gel electrophoresis (DGGE) analysis and subsequent prominent band sequencing, showing a quite stable community in the RDB, mainly attributed to the presence of T. versicolor. Pesticide removals were up to 54 % diuron and 48 % bentazon throughout the treatment. Afterwards, pesticide-contaminated wood chips were treated by T. versicolor in a solid biopile-like system. Hence, these results demonstrate that the microbial contamination constraint has definitely been overcome, and fungal bioremediation technology is ready to be implemented on a larger scale.

Bioremediation of organic pollutants by white rot fungal cytochrome P450: The role and mechanism of CYP450 in biodegradation

Cytochrome P450 (CYP450) is a well-known protein family that is widely distributed in many organisms. Members of this family have been implicated in a broad range of reactions involved in the metabolism of various organic compounds. Recently, an increasing number of studies have shown that the CYP450 enzyme also participates in the elimination and degradation of organic pollutants, by white rot fungi (WRF), a famous group of natural degraders. This paper reviews previous investigations of white rot fungal CYP450 involved in the biodegradation of organic pollutants, with a special focus on inhibitory experiments, and the direct and indirect evidence of the role of white rot fungal CYP450 in bioremediation. The catalytic mechanisms of white rot fungal CYP450, its application potential, and future prospect for its use in bioremediation are then discussed.

Enhanced degradation capability of white-rot fungi after short-term pre-exposure to silver ion: Performance and selectively antimicrobial mechanisms

Azo dyes in wastewater have great threats to environment and human health. White-rot fungi (WRF) have broad-spectrum potential for such refractory organics bioremediation; however, their applications are largely restrained by the poor viability owning to microbial invasion under non-sterile conditions. In this study, short-term pre-exposure to silver ion (Ag⁺) was demonstrated to be a practical, economic, and green method to enhance the perdurability of azo dyes decoloration by WRF Phanerochaete chrysosporium under non-sterile conditions. In control (without Ag⁺ pre-exposure), decoloration deactivated since cycle 7 (<10%), whereas in Ag⁺ pre-exposure groups, the decoloration ratios remained 91.5%-94.7% after 7 cycles. Variations in decoloration-related extracellular lignin enzyme activities were consistent with the decoloration effectiveness. The enhanced decoloration capability in Ag⁺ pre-exposure groups under non-sterile conditions could be ascribed to the selectively antimicrobial action by Ag⁺. The released Ag⁺ from the self-assembled silver nanoparticles (AgNPs) could selectively "stimulate" the proliferation and viability of P. chrysosporium, and simultaneously inhibit the growths of invasive microorganisms. The pyrosequencing results indicated that genus Sphingomonas (24.1%-31.3%) was the main invasive bacteria in Ag⁺ pre-exposure groups after long-term operation owing to the AgNPs passivation. As control, the invasive fungi (Asterotremella humicola) and bacteria (Burkholderia spp.) occurred in control after short-term operation, and genus Burkholderia (74.9%) dominated after long-term operation, leading to decoloration deactivation. Overall, these findings offer a new insight into the bio-nano interactions between WRF and invasive microorganisms in response to Ag⁺ or biogenic AgNPs, and could extend WRF application perspective under non-sterile conditions in future.

Bioremediation of 27 Micropollutants by Symbiotic Microorganisms of Wetland Macrophytes

Background: Micropollutants in bodies of water represent many challenges. We addressed these challenges by the application of constructed wetlands, which represent advanced treatment technology for the removal of micropollutants from water. However, which mechanisms specifically contribute to the removal efficiency often remains unclear. Methods: Here, we focus on the removal of 27 micropollutants by bioremediation. For this, macrophytes Phragmites australis, Iris pseudacorus and Lythrum salicaria were taken from established wetlands, and a special experimental set-up was designed. In order to better understand the impact of the rhizosphere microbiome, we determined the microbial composition using 16S rRNA gene sequencing and investigated the role of identified genera in the micropollutant removal of micropollutants. Moreover, we studied the colonization of macrophyte roots by arbuscular mycorrhizal fungi, which are known for their symbiotic relationship with plants. This symbiosis could result in increased removal of present micropollutants. Results: We found Iris pseudacorus to be the most successful bioremediative system, as it removed 22 compounds, including persistent ones, with more than 80% efficiency. The most abundant genera that contributed to the removal of micropollutants were Pseudomonas, Flavobacterium, Variovorax, Methylotenera, Reyranella, Amaricoccus and Hydrogenophaga. Iris pseudacorus exhibited the highest colonization rate (56%). Conclusions: Our experiments demonstrate the positive impact of rhizosphere microorganisms on the removal of micropollutants.

Genomic Analysis of Stropharia rugosoannulata Reveals Its Nutritional Strategy and Application Potential in Bioremediation

Stropharia rugosoannulata is not only a popular edible mushroom, but also has excellent potential in bioremediation. In this study, we present a high-quality genome of a monokaryotic strain of the S. rugosoannulata commercial cultivar in China. The assembly yielded an N50 length of 2.96 Mb and a total size of approximately 48.33 Mb, encoding 11,750 proteins. The number of heme peroxidase-encoding genes in the genome of S. rugosoannulata was twice the average of all of the tested Agaricales. The genes encoding lignin and xenobiotic degradation enzymes accounted for more than half of the genes encoding plant cell wall degradation enzymes. The expansion of genes encoding lignin and xenobiotic degradation enzymes, and cytochrome P450 involved in the xenobiotic metabolism, were responsible for its strong bioremediation and lignin degradation abilities. S. rugosoannulata was classified as a litter-decomposing (LD) fungus, based on the analysis of the cell wall degrading enzymes. Substrate selection for fruiting body cultivation should consider both the nutritional strategy of LD and a strong lignin degradation ability. Consistent with safe usage as an edible mushroom, the S. rugosoannulata genome does not contain genes for known psilocybin biosynthesis. Genome analysis will be helpful for understanding its nutritional strategy to guide fruiting body cultivation and for providing insight into its application in bioremediation.

Recent Progress and Prospects in Catalytic Water Treatment

Presently, conventional technologies in water treatment are not efficient enough to completely mineralize refractory water contaminants. In this context, the implementation of catalytic processes could be an alternative. Despite the advantages provided in terms of kinetics of transformation, selectivity, and energy saving, numerous attempts have not yet led to implementation at an industrial scale. This review examines investigations at different scales for which controversies and limitations must be solved to bridge the gap between fundamentals and practical developments. Particular attention has been paid to the development of solar-driven catalytic technologies and some other emerging processes, such as microwave assisted catalysis, plasma-catalytic processes, or biocatalytic remediation, taking into account their specific advantages and the drawbacks. Challenges for which a better understanding related to the complexity of the systems and the coexistence of various solid-liquid-gas interfaces have been identified.

Pesticide bioremediation by Trametes versicolor: Application in a fixed-bed reactor, sorption contribution and bioregeneration

Although immobilization on lignocellulosic materials has recently become a promising strategy in the fungal-based technology for micropollutant bioremediation, research evidence in this area is still scarce and significant knowledge gaps need to be addressed. In this study, Trametes versicolor immobilized on Quercus ilex wood chips was initially proposed to remove two pesticides, diuron and bentazon, from real agricultural wastewater. Thus, a bioremediation treatment was performed in a fixed-bed bioreactor at two empty bed contact times (EBCT) of 1 and 3 days. Bentazon saturation was achieved after 5 EBCTs, while diuron sorption remained below 50% even after 40 days of treatment. The differences in diuron and bentazon removals were linked to their different hydrophobicity and thus, affinity for wood. However, in any case, the sorption contribution of wood was found to be predominant compared to fungal biodegradation. These results motivated a comprehensive study to evaluate the pollutant sorption capacity of wood. Afterwards, pesticide-contaminated wood was successfully bioregenerated by T. versicolor in a biopile-like system, reaching high fungal colonization (up to 0.2451 mg ergosterol·g^-1 dry weight), degradation rate (up to 2.55 mg·g^-1·d^-1) and degradation yields (up to 92.50%). The combined treatment consisting of the fixed-bed bioreactor followed by the re-inoculated biopile showed the best performance in terms of fungal content and pesticide degradation. This is an important step toward the implementation of fungal-based technology for the removal of pesticides from agricultural water.

Comparison between two reactors using Trametes versicolor for agricultural wastewater treatment under non-sterile condition in sequencing batch mode

Agricultural wastewater is a major source of herbicides, which pose environmental and health concerns owing to their substantial use and poor elimination rate in conventional wastewater treatment plants. White-rot fungi are versatile in degrading xenobiotics; however, the key problem encountered with their application in actual scenarios is competition with indigenous microorganisms, mainly bacteria. To address this barrier, two different strategies were implemented in the present study. One strategy was to set up a trickle bed with Trametes versicolor immobilized on pine wood, and another strategy was to employ a T. versicolor-pelleted, fluidized-bed reactor to remove diuron and bentazon from actual wastewater under non-sterile conditions. The residence time in the trickle bed was estimated using three methodologies. With 10 batches of a 3-day cycle operation, although the trickle-bed reactor possessed a shorter contact time (8.5 h per cycle) and lower laccase activity compared with those of the fluidized-bed reactor, it demonstrated a higher removal yield and lower bacterial counts. In addition, the utilization of pine wood as a carrier obviously reduced the cost since no additional nutrients were required. Hence, after evaluating all advantages and limitations of both bioreactors, for the purpose of treating over the long term and scaling up, a trickle-bed reactor is the preferred choice.

Emerging Strategies for the Bioremediation of the Phenylurea Herbicide Diuron

Diuron (DUR) is a phenylurea herbicide widely used for the effective control of most annual and perennial weeds in farming areas. The extensive use of DUR has led to its widespread presence in soil, sediment, and aquatic environments, which poses a threat to non-target crops, animals, humans, and ecosystems. Therefore, the removal of DUR from contaminated environments has been a hot topic for researchers in recent decades. Bioremediation seldom leaves harmful intermediate metabolites and is emerging as the most effective and eco-friendly strategy for removing DUR from the environment. Microorganisms, such as bacteria, fungi, and actinomycetes, can use DUR as their sole source of carbon. Some of them have been isolated, including organisms from the bacterial genera Arthrobacter, Bacillus, Vagococcus, Burkholderia, Micrococcus, Stenotrophomonas, and Pseudomonas and fungal genera Aspergillus, Pycnoporus, Pluteus, Trametes, Neurospora, Cunninghamella, and Mortierella. A number of studies have investigated the toxicity and fate of DUR, its degradation pathways and metabolites, and DUR-degrading hydrolases and related genes. However, few reviews have focused on the microbial degradation and biochemical mechanisms of DUR. The common microbial degradation pathway for DUR is via transformation to 3,4-dichloroaniline, which is then metabolized through two different metabolic pathways: dehalogenation and hydroxylation, the products of which are further degraded via cooperative metabolism. Microbial degradation hydrolases, including PuhA, PuhB, LibA, HylA, Phh, Mhh, and LahB, provide new knowledge about the underlying pathways governing DUR metabolism. The present review summarizes the state-of-the-art knowledge regarding (1) the environmental occurrence and toxicity of DUR, (2) newly isolated and identified DUR-degrading microbes and their enzymes/genes, and (3) the bioremediation of DUR in soil and water environments. This review further updates the recent knowledge on bioremediation strategies with a focus on the metabolic pathways and molecular mechanisms involved in the bioremediation of DUR.

A comprehensive insight into the application of white rot fungi and their lignocellulolytic enzymes in the removal of organic pollutants

Environmental problems resultant from organic pollutants are a major current challenge for modern societies. White rot fungi (WRF) are well known for their extensive organic compound degradation abilities. The unique oxidative and extracellular ligninolytic systems of WRF that exhibit low substrate specificity, enable them to display a considerable ability to transform or degrade different environmental contaminants. In recent decades, WRF and their ligninolytic enzymes have been widely applied in the removal of polycyclic aromatic hydrocarbons (PAHs), pharmaceutically active compounds (PhACs), endocrine disruptor compounds (EDCs), pesticides, synthetic dyes, and other environmental pollutants, wherein promising results have been achieved. This review focuses on advances in WRF-based bioremediation of organic pollutants over the last 10 years. We comprehensively document the application of WRF and their lignocellulolytic enzymes for removing organic pollutants. Moreover, potential problems and intriguing observations that are worthy of additional research attention are highlighted. Lastly, we discuss trends in WRF-remediation system development and avenues that should be considered to advance research in the field.

Fungal degradation of selected medium to highly polar pesticides by Trametes versicolor: kinetics, biodegradation pathways, and ecotoxicity of treated waters

The massive use of pesticides represents one of the main causes of environmental deterioration, as they have adverse effects on non-target organisms. Thus, the development of technologies capable of reducing their release into the environment is urgently needed. This study reports for the first time the white-rot fungus Trametes versicolor as an alternative towards the degradation of medium to highly polar pesticides such as the organophosphate malathion, and the neonicotinoids acetamiprid and imidacloprid. Specifically, T. versicolor could completely remove 1 mg/L of malathion in an Erlenmeyer flask within 48 h, while experiments of acetamiprid and imidacloprid (4 mg/L), conducted in air-pulse fluidized bioreactors, resulted in degradation percentages of 20% and 64.7%, respectively, after 7 days of operation. Enzymatic exploration studies revealed that the cytochrome P450 system, instead of the extracellular enzyme laccase, is involved in the degradation of acetamiprid and imidacloprid. The degradation pathways were proposed based on the main transformation products (TPs) formed in the solutions: seven in the case of malathion, and two and one in the case of imidacloprid and acetamiprid, respectively. Although the TPs identified were predicted to be less toxic than the investigated pesticides, the toxicity of the individual solutions slightly increased throughout the degradation process, according to the Microtox assay. However, the solution toxicity was always below the threshold established in the local regulation. Although additional research is needed to implement this treatment at a pilot plant scale, this work highlights the potential of T. versicolor to bio-remediate pesticide-contaminated waters.

Degradation of the Organochlorinated Herbicide Diuron by Rainforest Basidiomycetes

The main organochlorinated compounds used on agricultural crops are often recalcitrant, affecting nontarget organisms and contaminating rivers or groundwater. Diuron (N-(3,4-dichlorophenyl)-N',N'-dimethylurea) is a chlorinated herbicide widely used in sugarcane plantations. Here, we evaluated the ability of 13 basidiomycete strains of growing in a contaminated culture medium and degrading the xenobiotic. Dissipation rates in culture medium with initial 25 mg/L of diuron ranged from 7.3 to 96.8%, being Pluteus cubensis SXS 320 the most efficient strain, leaving no detectable residues after diuron metabolism. Pycnoporus sanguineus MCA 16 removed 56% of diuron after 40 days of cultivation, producing three metabolites more polar than parental herbicide, two of them identified as being DCPU and DCPMU. Despite of the strong inductive effect of diuron upon laccase synthesis and secretion, the application of crude enzymatic extracts of P. sanguineus did not catalyzed the breakdown of the herbicide in vitro, indicating that diuron biodegradation was not related to this oxidative enzyme.