OPFR removal by white rot fungi: screening of removers and approach to the removal mechanism.

The persistent presence of organophosphate flame retardants (OPFRs) in wastewater (WW) effluents raises significant environmental and health concerns, highlighting the limitations of conventional treatments for their remotion. Fungi, especially white rot fungi (WRF), offer a promising alternative for OPFR removal. This study sought to identify fungal candidates (from a selection of four WRF and two Ascomycota fungi) capable of effectively removing five frequently detected OPFRs in WW: tributyl phosphate (TnBP), tributoxy ethyl phosphate (TBEP), trichloroethyl phosphate (TCEP), trichloro propyl phosphate (TCPP) and triethyl phosphate (TEP). The objective was to develop a co-culture approach for WW treatment, while also addressing the utilization of less assimilable carbon sources present in WW. Research was conducted on carbon source uptake and OPFR removal by all fungal candidates, while the top degraders were analyzed for biomass sorption contribution. Additionally, the enzymatic systems involved in OPFR degradation were identified, along with toxicity of samples after fungal contact. Acetate (1.4 g·L-1), simulating less assimilable organic matter in the carbon source uptake study, was eliminated by all tested fungi in 4 days. However, during the initial screening where the removal of four OPFRs (excluding TCPP) was tested, WRF outperformed Ascomycota fungi. Ganoderma lucidum and Trametes versicolor removed over 90% of TnBP and TBEP within 4 days, with Pleorotus ostreatus and Pycnoporus sanguineus also displaying effective removal. TCEP removal was challenging, with only G. lucidum achieving partial removal (47%). A subsequent screening with selected WRF and the addition of TCPP revealed TCPP's greater susceptibility to degradation compared to TCEP, with T. versicolor exhibiting the highest removal efficiency (77%). This observation, plus the poor degradation of TEP by all fungal candidates suggests that polarity of an OPFR inversely correlates with its susceptibility to fungal degradation. Sorption studies confirmed the ability of top-performing fungi of each selected OPFR to predominantly degrade them. Enzymatic system tests identified the CYP450 intracellular system responsible for OPFR degradation, so reactions of hydroxylation, dealkylation and dehalogenation are possibly involved in the degradation pathway. Finally, toxicity tests revealed transformation products obtained by fungal degradation to be more toxic than the parent compounds, emphasizing the need to identify them and their toxicity contributions. Overall, this study provides valuable insights into OPFR degradation by WRF, with implications for future WW treatment using mixed consortia, emphasizing the importance of reducing generated toxicity.

Whole-genome sequencing of Sphingobium baderi SC-1 and identification of a crucial 3-phenoxybenzoic acid-degrading gene.

As an efficient degradation strain, Sphingobium baderi SC-1 can breakdown 3-phenoxybenzoic acid (3-PBA) with high proficiency. To investigate the internal factors that regulate this process, we conducted whole-genome sequencing and successfully identified the pivotal 3-PBA-degrading gene sca (1,230 bp). After sca was expressed in engineered bacteria, a remarkable degradation efficiency was observed, as 20 mg/L 3-PBA was almost completely decomposed within 24 h. The phenol was formed as one of the degradation products. Notably, in addition to their ability to degrade 3-PBA, the resting cells proficiently degraded 4'-HO-3-PBA and 3'-HO-4-PBA. In conclusion, we successfully identified and validated sca as the pivotal enzyme responsible for the efficient degradation of 3-PBA from Sphingomonas baderi, providing a crucial theoretical foundation for further explorations on the degradation potential of SC-1.

Novel method for rapid monitoring of OPFRs by LLE and GC-MS as a tool for assessing biodegradation: validation and applicability.

Organophosphate flame retardants (OPFRs) are high-production volume chemicals widely present in environmental compartments. The presence of water-soluble OPFRs (tri-n-butyl phosphate (TnBP), tris(2-butoxyethyl) phosphate (TBEP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP), and triethyl phosphate (TEP)) in water compartments evidences the struggle of conventional wastewater treatment plants (WWTPs) to effectively eliminate these toxic compounds. This study reports for the first time the use of white-rot fungi as a promising alternative for the removal of these OPFRs. To accomplish this, a simple and cost-efficient quantification method for rapid monitoring of these contaminants' concentrations by GC-MS while accounting for matrix effects was developed. The method proved to be valid and reliable for all the tested parameters. Sample stability was examined under various storage conditions, showing the original samples to be stable after 60 days of freezing, while post-extraction storage techniques were also effective. Finally, a screening of fungal degraders while assessing the influence of the glucose regime on OPFR removal was performed. Longer chain organophosphate flame retardants, TBP and TBEP, could be easily and completely removed by the fungus Ganoderma lucidum after only 4 days. This fungus also stood out as the sole organism capable of partially degrading TCEP (35% removal). The other chlorinated compound, TCPP, was more easily degraded and 70% of its main isomer was removed by T. versicolor. However, chlorinated compounds were only partially degraded under nutrient-limiting conditions. TEP was either not degraded or poorly degraded, and it is likely that it is a transformation product from another OPFR's degradation. These results suggest that degradation of chlorinated compounds is dependent on the concentration of the main carbon source and that more polar OPFRs are less susceptible to degradation, given that they are less accessible to radical removal by fungi. Overall, the findings of the present study pave the way for further planned research and a potential application for the degradation of these contaminants in real wastewaters.

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.

Combining fungal bioremediation and ozonation for rinse wastewater treatment.

In this work, agricultural rinse wastewater, which is produced during the cleaning of agricultural equipment and constitutes a major source of pesticides, was treated by fungal bioremediation and ozonation, both individually and combined in a two-stage treatment train. Three major pesticides (thiacloprid, chlortoluron, and pyrimethanil) were detected in rinse wastewater, with a total concentration of 38.47 mg C L-1. Comparing both technologies, ozonation in a stirred reactor achieved complete removal of these pesticides (720 min) while proving to be a more effective approach for reducing colour, organic matter, and bacteria. However, this technique produced transformation products and increased toxicity. In contrast, fungal bioremediation in a rotating drum bioreactor attenuated toxicity levels and did not produce such metabolites, but only removed approximately 50 % of target pesticide - hydraulic retention time (HRT) of 5 days - and obtained worse results for most of the general quality parameters studied. This work also includes a preliminary economic assessment of both technologies, revealing that fungal bioremediation was 2 times more cost-effective than ozonation. The treatment train, consisting of a first stage of fungal bioremediation followed by ozonation, was found to be a promising approach as it synergistically combines the advantages of both treatments, achieving high removals of pesticides (up to 100 %) and transformation products, while reducing operating costs and producing a biodegradable effluent. This is the first time that fungal bioremediation and ozonation technologies have been compared and combined in a treatment train to deal with pesticides in agricultural rinse wastewater.

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.

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.

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.

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.

Prospects on coupling UV/H2O2 with activated sludge or a fungal treatment for the removal of pharmaceutically active compounds in real hospital wastewater.

Conventional active sludge (AS) process at municipal centralized wastewater treatment facilities may exhibit little pharmaceuticals (PhACs) removal efficiencies when treating hospital wastewater (HWW). Therefore, a dedicated efficient wastewater treatment at the source point is recommended. In this sense, advanced oxidation processes (AOPs) and fungal treatment (FG) have evidenced promising results in degrading PhACs. The coupling of the AOP based on UV/H2O2 treatment with biological treatment (AS or FG) treating a real non-sterile HWW, was evaluated in this work. In addition, a coagulation-flocculation pretreatment was applied to improve the efficiency of all approaches. Twenty-two PhACs were detected in raw HWW, which were effectively removed (93-95%) with the combination of any of the biological treatment followed by UV/H2O2 treatment. Similar removal results (94%) were obtained when placing UV/H2O2 treatment before FG, while a lower removal (83%) was obtained in the combination of UV/H2O2 followed by AS. However, the latest was the only treatment combination that achieved a decrease in the toxicity of water. Moreover, deconjugation of conjugated PhACs has been suggested for ofloxacin and lorazepam after AS treatment, and for ketoprofen after fungal treatment. Monitoring of carbamazepine and its transformation products along the treatment allowed to identify the same carbamazepine degradation pathway in UV/H2O2 and AS treatments, unlike fungal treatment, which followed another degradation route.

Remediation of bentazone contaminated water by Trametes versicolor: Characterization, identification of transformation products, and implementation in a trickle-bed reactor under non-sterile conditions.

Bentazone, an herbicide widely applied in rice and cereal crops, is widespread in the aquatic environment. This study evaluated the capacity of Trametes versicolor to remove bentazone from water. The fungus was able to completely remove bentazone after three days at Erlenmeyer-scale incubation. Both laccase and cytochrome P450 enzymatic systems were involved in bentazone degradation. A total of 19 transformation products (TPs) were identified to be formed during the process. The reactions involved in their formation included hydroxylations, oxidations, methylations, N-nitrosation, and dimerization. A laccase mediated radical mechanism was proposed for TP formation. In light of the results obtained at the Erlenmeyer scale, a trickle-bed reactor with T. versicolor immobilized on pine wood chips was set up to evaluate its stability during bentazone removal under non-sterile conditions. After 30 days of sequencing batch operation, an average bentazone removal of 48% was obtained, with a considerable contribution of adsorption onto the lignocellulosic support material. Bacterial contamination, which is the bottleneck in the implementation of fungal bioreactors, was successfully addressed by this particular system according to its maintained performance. This research is a pioneering step forward to the implementation of fungal bioremediation on a real scale.

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.

The occurrence of the extensively used herbicide diuron in the environment poses a severe threat to the ecosystem and human health. Four different ligninolytic fungi were studied as biodegradation candidates for the removal of diuron. Among them, T. versicolor was the most effective species, degrading rapidly not only diuron (83%) but also the major metabolite 3,4-dichloroaniline (100%), after 7-day incubation. During diuron degradation, five transformation products (TPs) were found to be formed and the structures for three of them are tentatively proposed. According to the identified TPs, a hydroxylated intermediate 3-(3,4-dichlorophenyl)-1-hydroxymethyl-1-methylurea (DCPHMU) was further metabolized into the N-dealkylated compounds 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3,4-dichlorophenylurea (DCPU). The discovery of DCPHMU suggests a relevant role of hydroxylation for subsequent N-demethylation, helping to better understand the main reaction mechanisms of diuron detoxification. Experiments also evidenced that degradation reactions may occur intracellularly and be catalyzed by the cytochrome P450 system. A response surface method, established by central composite design, assisted in evaluating the effect of operational variables in a trickle-bed bioreactor immobilized with T. versicolor on diuron removal. The best performance was obtained at low recycling ratios and influent flow rates. Furthermore, results indicate that the contact time between the contaminant and immobilized fungi plays a crucial role in diuron removal. This study represents a pioneering step forward amid techniques for bioremediation of pesticides-contaminated waters using fungal reactors at a real scale.

Exploring the degradation capability of Trametes versicolor on selected hydrophobic pesticides through setting sights simultaneously on culture broth and biological matrix.

Pesticides introduced inadvertently or deliberately into environment by global agricultural practices have caused growing public concern, therefore the search of approaches for elimination of such xenobiotics should be motivated. The degradation of hydrophobic pesticides including chlorpyrifos, dicofol and cypermethrin were assayed with the white-rot fungus Trametes versicolor. Experiments were set at realistic concentration as 5 µg L-1, and both culture medium and biologic matrix were analyzed for pollutants residues. Results showed that the first step was due to a fast adsorption, which also played an important role, accounting for more than 90% removal in average. Then mass balances proposal evidenced the biodegradation of the adsorbed pollutants, demonstrating efficient depletion as 94.7%, 87.9% and 93.1%, respectively. Additionally, the related degradation metabolites were identified using ultra performance liquid chromatography coupled to high resolution mass spectrometry. Two compounds, namely O,O-diethyl thiophosphate and diethyl phosphate were detected as transformation products of chlorpyrifos, whereas dicofol was degraded into benzaldehyde that is first time to be reported. It also confirms the degradation capability of T. versicolor. Our results suggest that T. versicolor is a potential microorganism for bioremediation of hydrophobic pesticide contaminated environments.

The removal of diuron from agricultural wastewaters by Trametes versicolor immobilized on pinewood in simple channel reactors.

The presence of pesticides in agricultural wastewater entails harmful risks to both the environment and public health. In this study, two channel-type bioreactors with Trametes versicolor immobilized on pinewood chips were evaluated in terms of the removal efficiency of diuron from agricultural wastewater under non-sterile conditions. First, both single and successive sorption processes of diuron on pinewood chips were evaluated. The Freundlich model showed the best correlation in the sorption isotherm study (R2 = 0.993; Δq = 5.245), but according to repeated sorption experiments, the Langmuir model (R2 = 0.993; Δq = 5.757) was considered more representative. Equilibrium was reached after approximately 48 h, and the Elovich kinetic model gave the best fit with the experimental data. A packed-bed channel bioreactor (PBCB) was found to be a remarkable alternative able to remove up to 94% diuron from agricultural wastewater during 35 d. However, periodic manual mixing was required to guarantee an aerobic process, and a rotating drum bioreactor (RDB) was subsequently proposed as an enhanced version. The RDB removed up to 61% diuron during 16 d using almost 7 times lower wood dose (152 g wood·L-1) than in the PBCB (1000 g wood·L-1).

Long-term continuous treatment of non-sterile real hospital wastewater by Trametes versicolor.

BACKGROUND: Hospital wastewater is commonly polluted with high loads of pharmaceutically active compounds, which pass through wastewater treatment plants (WWTPs) and end up in water bodies, posing ecological and health risks. White-rot fungal treatments can cope with the elimination of a wide variety of micropollutants while remaining ecologically and economically attractive. Unfortunately, bacterial contamination has impeded so far a successful implementation of fungal treatment for real applications. RESULTS: This work embodied a 91-day long-term robust continuous fungal operation treating real non-sterile hospital wastewater in an air pulsed fluidized bed bioreactor retaining the biomass. The hydraulic retention time was 3 days and the ageing of the biomass was avoided through partial periodic biomass renovation resulting in a cellular retention time of 21 days. Evolution of microbial community and Trametes abundance were evaluated. CONCLUSIONS: The operation was able to maintain an average pharmaceutical load removal of over 70% while keeping the white-rot fungus active and predominant through the operation.

Fungal treatment of metoprolol and its recalcitrant metabolite metoprolol acid in hospital wastewater: Biotransformation, sorption and ecotoxicological impact.

Hospital wastewater (HWW) effluents represent an important source of contaminants such as pharmaceutical compounds and their human metabolites. To better evaluate dedicated treatment of hospital effluents for pollutant mitigation, not only the parent compounds should be considered but also the intermediates generated during treatment. The metabolite metoprolol acid (MTPA) has been found in urban wastewaters at higher concentration than its parent compound metoprolol (MTP), being more recalcitrant to biodegradation. The aim of this study was to investigate degradation, transformation and sorption of the ß-blocker MTP, and its recalcitrant metabolite MTPA, during water treatment based on the fungi Ganoderma lucidum, Trametes versicolor and Pleurotus ostreatus. Fourteen intermediates were identified in MTP biotransformation while five of them also attributed to MTPA biodegradation and two to MTPA only. Their identification allowed their correlation in separate biotransformation pathways suggested. The highest degradation rate of metoprolol (up to 51%) and metoprolol acid (almost 77%) was found after 15-days treatment with Ganoderma lucidum, with an increase in toxicity up to 29% and 4%, respectively. This fungus was further selected for treating real HWW in a batch fluidized bed bioreactor (FBB). Treated wastewater and fungal biomass samples were used to evaluate the distribution of the target compounds and the intermediates identified between solid and liquid phases. While similar elimination capabilities were observed for the removal of metoprolol, and even higher for its persistent metabolite metoprolol acid, the extent on compound transformation diminished considerably compared with the study treating purified water: a high level of the persistent α-HMTP and TP240 were still present in effluent samples (15% and 6%, respectively), being both TPs present at high proportion (up to 28%) in fungal biomass. This is the first time that pharmaceutical TPs have been investigated in the fungal biomass.

Fungal biodegradation of the N-nitrosodimethylamine precursors venlafaxine and O-desmethylvenlafaxine in water.

Antidepressant drugs such as Venlafaxine (VFX) and O-desmethylvenlafaxine (ODMVFX) are emerging contaminants that are commonly detected in aquatic environments, since conventional wastewater treatment plants are unable to completely remove them. They can be precursors of hazardous by-products, such as the carcinogenic N-nitrosodimethylamine (NDMA), generated upon water chlorination, as they contain the dimethylamino moiety, necessary for the formation of NDMA. In this study, the capability of three white rot fungi (Trametes versicolor, Ganoderma lucidum and Pleurotus ostreatus) to remove both antidepressants from water and to decrease NDMA formation potential was investigated. Furthermore, transformation by-products (TPs) generated along the treatment process were elucidated and also correlated with their NDMA formation potential. Very promising results were obtained for T. versicolor and G. lucidum, both being able to remove up to 100% of ODMVFX. In the case of VFX, which is very recalcitrant to conventional wastewater treatment, a 70% of removal was achieved by T. versicolor, along with a reduction in NDMA formation potential, thus decreasing the associated problems for human health and the environment. However, the NDMA formation potential remained practically constant during treatment with G. lucidum despite of the equally high VFX removal (70%). This difference was attributed to the generation of different TPs during both fungal treatments. For example, G. lucidum generated more ODMVFX, which actually has a higher NDMA formation potential than the parent compound itself.

Can white-rot fungi be a real wastewater treatment alternative for organic micropollutants removal? A review.

Micropollutants are a diverse group of compounds that are detected at trace concentrations and may have a negative effect on the environment and/or human health. Most of them are unregulated contaminants, although they have raised a concern in the scientific and global community and future regulation might be written in the near future. Several approaches have been tested to remove micropollutants from wastewater streams. In this manuscript, a focus is placed in reactor biological treatments that use white-rot fungi. A critical review of white-rot fungal-based technologies for micropollutant removal from wastewater has been conducted, several capabilities and limitations of such approaches have been identified and a range of solutions to overcome most of the limitations have been reviewed and/or proposed. Overall, this review argues that white-rot fungal reactors could be an efficient technology to remove micropollutants from specific wastewater streams.