Potential of enzymatic process as an innovative technology to remove anticancer drugs in wastewater

Removal of the cytostatic drugs bleomycin and vincristine by white-rot fungi under various conditions, and determination of enzymes involved, degradation by-products, and toxicity

Anticancer drugs show recalcitrance to conventional wastewater treatments; thus, they are present in aquatic systems and pose an environmental threat. Fungi represent a promising biological alternative for wastewater treatments. Therefore, the goals of this work were to assess the potential of white-rot fungi (Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH), and Trametes versicolor (CB8)) for removing bleomycin and vincristine, and to investigate the impacts of various conditions (shaking, aeration, or biomass immobilization) on the process. The removal capacities were measured using Ultra-Performance Liquid Chromatography (UPLC) coupled with Mass Spectrometry (MS) and preceded by Solid Phase Extraction (SPE). We further identified major drugs degradation products; determined the fungi's main enzyme activity profiles (laccase, manganese and lignin peroxidases); and examined the toxicities of post-processed samples against Lemna minor, Daphnia magna and Pseudomonas putida. In just 2 days, all strains (except for P. nidulans) removed >90 % of vincristine, nearly completely eliminating the drug over time. Bleomycin content reduction occurred with T. versicolor or H. fasciculare, respectively reaching 55 % and 83 % drug elimination after 9 days. Oxygen was found to be crucial for cytostatics degradation, with their highest removal rates occurring in samples with air supply (aeration or agitation). Laccase was the only tested enzyme associated with cytostatics elimination. Drug biodegradation was followed by detoxification, demonstrating the utility of fungi in cytostatics removal.

Functionalization of porous silica with graphene oxide and polyethyleneimine, containing zinc copper ferrite nanoparticles for water treatment and antibacterial application

The article discusses the removal of methylene blue (MB) dye, a common cationic dye used in the textile industry, from aqueous solutions through an adsorption process. The use of porous components as adsorbents are shown to facilitate complete separation after the process is completed. The substrate was synthesized by connecting zinc copper ferrite (ZnCuFe2O4), polyethyleneimine (PEI), and Graphene Oxide (GO) sheets to MCM-48, which is a mesoporous material. The surface of MCM-48 was modified using CPTMS, which created an O-Si-Cl bridge, thereby improving the adsorption rate. The substrate was shown to have suitable sites for electrostatic interactions and creating hydrogen bonds with MB. The adsorption process from the Freundlich isotherm (R2 = 0.9224) and the pseudo-second-order diagram (R2 = 0.9927) demonstrates the adsorption of several layers of dye on the heterogeneous surface of the substrate. The synthesized substrate was also shown to have good bactericidal activity against E. coli and S. aureus bacterial strain. Furthermore, the substrate maintained its initial ability to adsorb MB dye for four consecutive cycles. The research resulted that ZnCuFe2O4@MCM-48/PEI-GO substrate has the potential for efficient and economical removal of MB dye from aqueous solutions (R = 88.82%) (qmax = 294.1176 mg. g-1), making it a promising solution for the disposal of harmful industrial waste.

Laccases as Effective Tools in the Removal of Pharmaceutical Products from Aquatic Systems

This review aims to provide a comprehensive overview of the application of bacterial and fungal laccases for the removal of pharmaceuticals from the environment. Laccases were evaluated for their efficacy in degrading pharmaceutical substances across various categories, including analgesics, antibiotics, antiepileptics, antirheumatic drugs, cytostatics, hormones, anxiolytics, and sympatholytics. The capability of laccases to degrade or biotransform these drugs was found to be dependent on their structural characteristics. The formation of di-, oligo- and polymers of the parent compound has been observed using the laccase mediator system (LMS), which is advantageous in terms of their removal via commonly used processes in wastewater treatment plants (WWTPs). Notably, certain pharmaceuticals such as tetracycline antibiotics or estrogen hormones exhibited degradation or even mineralization when subjected to laccase treatment. Employing enzyme pretreatment mitigated the toxic effects of degradation products compared to the parent drug. However, when utilizing the LMS, careful mediator selection is essential to prevent potential increases in environment toxicity. Laccases demonstrate efficiency in pharmaceutical removal within WWTPs, operating efficiently under WWTP conditions without necessitating isolation.

Methotrexate degradation in artificial wastewater using non-thermal pencil plasma jet

The rising global cancer rate is driving up the consumption of anticancer drugs. This causing a noticeable increase in the levels of these drugs in wastewater. The drugs are not metabolized effectively by the human body, leading to their presence in human waste, as well as in the effluent from hospitals and drug manufacturing industries. Methotrexate is a commonly used drug for treating various types of cancer. Its complex organic structure makes it difficult to degrade using conventional methods. The present work proposed a non-thermal pencil plasma jet treatment for methotrexate degradation. The air plasma produced in this jet setup is electrical characterized and plasma species/radicals are identified using emission spectroscopy. The degradation of drug is monitored by studying the change in solution physiochemical properties, HPLC-UV analysis, and removal of total organic carbon, etc.Results show that a 9-min plasma treatment completely degraded the drug solution that followed first-order degradation kinetics with rate constant 0.38 min^-1 and 84.54% mineralization was observed. Additionally, an increase in electrical conductivity and dissolved solids compared to virgin water-plasma interaction indicated the formation of new, smaller compounds (2,4-Diaminopteridine-6-carboxylic acid, N-(4-Aminobenzoyl)-L-glutamic acid, etc.) after drug degradation. The plasma-treated methotrexate solution also showed lower toxicity toward freshwater chlorella algae compared to the untreated solution. Finally, it can be said that non-thermal plasma jets are economically and environmentally friendly devices that have the potential to be used for the treatment of complex and resistive anticancer drug-polluted wastewaters.

Genipin and glutaraldehyde based laccase two-layers immobilization with improved properties: New biocatalysts with high potential for enzymatic removal of trace organic contaminants

This research proposes the preparation of a two-layer laccase biocatalyst using genipin or/and glutaraldehyde as cross-linking agents. The multilayer biocatalysts were prepared using different combinations of genipin and glutaraldehyde in the individual preparation of the first and second laccase layers. First, chitosan was treated with genipin or glutaraldehyde, followed by the immobilization of the first laccase layer to form a single-layer biocatalyst. Then, the immobilized laccases were coated once again with genipin or glutaraldehyde, and a new laccase layer was immobilized onto the system, resulting in the final two-layer biocatalyst. Compared to the single-layer biocatalysts, catalytic activity increased 1.7- and 3.4-fold when glutaraldehyde coating was used to prepare the second laccase layer. However, adding a second layer did not always produce more active biocatalysts, since the two-layer biocatalysts prepared with genipin (GenLacGenLac and GluLacGenLac) presented a decrease in activity of 65% and 28%, respectively. However, these two-layer biocatalysts prepared with genipin maintained 100% of their initial activity after 5 cycles of ABTS oxidation. Nevertheless, the two-layer, genipin-coated biocatalyst resulted in a higher removal of trace organic contaminants, since it removed 100% of mefenamic acid and 66% of acetaminophen, compared with the glutaraldehyde-coated biocatalyst, which removed 20% of mefenamic acid, and 18% of acetaminophen.

Anticancer drugs in wastewater and natural environments: A review on their occurrence, environmental persistence, treatment, and ecological risks

The consumption of anticancer drugs (also known as chemotherapy drugs or antineoplastic drugs) has augmented over the last decades due to increased cancer incidence. Although there is an increasing concern about the presence of pharmaceutical compounds in natural environments and urban/domestic wastewater, anticancer drugs used in chemotherapy and anticancer medication have received less attention. In this review, the occurrence, environmental persistence, and known and potential ecological impacts of anticancer drugs is discussed. This review shows that these compounds are being increasingly detected in effluents of hospitals, influents and effluents of wastewater treatment plants, river surface water and sediments, groundwater, and even drinking water. Anticancer drugs can impact aquatic organisms such as algae, crustaceans, rotifers, and fish and may promote changes in soil and water microbial communities that may alter ecosystem functioning. Our knowledge of technologies for the removal of anticancer drugs is still limited, and these drugs can be dispersed in nature in a diffuse way in an uncontrolled manner. For this reason, an improved understanding of the presence, persistence, and ecological impacts of anticancer drugs in wastewater and natural environments is needed to help design management strategies, protect aquatic microorganisms, and mitigate potential ecological impacts.

Study of Membrane-Immobilized Oxidoreductases in Wastewater Treatment for Micropollutants Removal

The development of efficient strategies for wastewater treatment to remove micropollutants is of the highest importance. Hence, in this study, we presented a rapid approach to the production of biocatalytic membranes based on commercially available cellulose membrane and oxidoreductase enzymes including laccase, tyrosinase, and horseradish peroxidase. Effective enzyme deposition was confirmed based on Fourier transform infrared spectra, whereas results of spectrophotometric measurements showed that immobilization yield for all proposed systems exceeded 80% followed by over 80% activity recovery, with the highest values (over 90%) noticed for the membrane-laccase system. Further, storage stability and reusability of the immobilized enzyme were improved, reaching over 75% after, respectively, 20 days of storage, and 10 repeated biocatalytic cycles. The key stage of the study concerned the use of produced membranes for the removal of hematoporphyrin, (2,4-dichlorophenoxy)acetic acid (2,4-D), 17α-ethynylestradiol, tetracycline, tert-amyl alcohol (anesthetic drug), and ketoprofen methyl ester from real wastewater sampling at various places in the wastewater treatment plant. Although produced membranes showed mixed removal rates, all of the analyzed compounds were at least partially removed from the wastewater. Obtained data clearly showed, however, that composition of the wastewater matrix, type of pollutants as well as type of enzyme strongly affect the efficiency of enzymatic treatment of wastewater.

Bioremoval and Detoxification of the Anticancer Drug Mitoxantrone Using Immobilized Crude Versatile Peroxidase (icVP/Ba) Bjerkandera adusta CCBAS 930

The aim of this study was to evaluate the biodecolorization and detoxification of the anticancer drug mitoxantron (MTX) by immobilized crude versatile peroxidase of Bjerkandera adusta CCBAS 930 (icVP/Ba). The concentrated crude VP was obtained from B. adusta CCBAS 930 culture on medium with MTX (µg/mL) addition, immobilized with 4% sodium alginate. MTX removal degree (decolorization), levels of phenolic compounds and free radicals were determined during MTX biotransformation. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (multi-species microbial assay, MARA), and genotoxicity (SOS Chromotest) of MTX were evaluated before and after the biological treatment. The use of icVP/Ba (95 U/mL) significantly shortened the bioremoval of 10 µg/mL MTX (95.57% after 72 h). MTX removal by icVP/Ba was correlated with an 85% and 90% decrease in the levels of phenolic compounds and free radicals, respectively. In addition, the use of icVP/Ba contributed to a decrease in the phyto-, bio-, and genotoxicity of MTX. This is the first study to describe the possibility of removing MTX using immobilized crude fungal peroxidase.

Challenges of TiO2 heterogeneous photocatalysis on cytostatic compounds degradation: state of the art

The following work provides a perspective on the degradation of cytostatic pollutants through TiO₂ heterogeneous photocatalysis. Cytostatic drugs are emerging pollutants used for cancer treatment found in hospital and domestic wastewater. Small amounts of cytostatic pollutants may pose severe health problems in human beings, animals, and plants after prolonged contact. This research presents a general review of some water treatment methods, such as aerobic activated sludge, enzymatic degradation, nanofiltration and chlorination, that have been used for the degradation or elimination of cytostatic drugs in wastewater. In recent years, photocatalysis has become important to solve this problem; these advanced oxidation process uses pure and modified TiO₂ to degrade cytostatic contaminants and convert them into non-harmful substances or to eliminate them completely. This work contains a comprehensive review of the heterogeneous photocatalysis process and mechanism, and its application on the removal of cytostatic pollutants. Even if research on the topic is still scarce, this literature review provides interesting highlights on the scope of the research field, and the path such research could follow.

Ferrate (VI), Fenton Reaction and Its Modification: An Effective Method of Removing SARS-CoV-2 RNA from Hospital Wastewater

The outbreak of the coronavirus disease 2019 (COVID-19) raises questions about the effective inactivation of its causative agent, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in medical wastewater by disinfectants. For this reason, our study of wastewater from a selected hospital evaluated several different advanced oxidation methods (Fenton reaction and Fenton-like reaction and ferrate (VI)) capable of effectively removing SARS-CoV-2 RNA. The obtained results of all investigated oxidation processes, such as ferrates, Fenton reaction and its modifications achieved above 90% efficiency in degradation of SARS-CoV-2 RNA in model water. The efficiency of degradation of real SARS-CoV-2 from hospital wastewater declines in following order ferrate (VI) > Fenton reaction > Fenton-like reaction. Similarly, the decrease of chemical oxygen demand compared to effluent was observed. Therefore, all of these methods can be used as a replacement of chlorination at the wastewater effluent, which appeared to be insufficient in SARS-CoV-2 removal (60%), whereas using of ferrates showed efficiency of up to 99%.

Laccases—Versatile Enzymes Used to Reduce Environmental Pollution

The accumulation of waste and toxic compounds has become increasingly harmful to the environment and human health. In this context, the use of laccases has become a focus of interest, due to the properties of these versatile enzymes: low substrate specificity, and water formation as a non-toxic end product. Thus, we begin our study with a general overview of the importance of laccase for the environment and industry, starting with the sources of laccases (plant, bacterial and fungal laccases), the structure and mechanism of laccases, microbial biosynthesis, and the immobilization of laccases. Then, we continue with an overview of agro-waste treatment by laccases wherein we observe the importance of laccases for the biodisponibilization of substrates and the biodegradation of agro-industrial byproducts; we then show some aspects regarding the degradation of xenobiotic compounds, dyes, and pharmaceutical products. The objective of this research is to emphasize and fully investigate the effects of laccase action on the decomposition of lignocellulosic materials and on the removal of harmful compounds from soil and water, in order to provide a sustainable solution to reducing environmental pollution.

Biodegradation of cyclophosphamide and etoposide by white rot fungi and their degradation kinetics

The biodegradation of cyclophosphamide and etoposide by Trametes versicolor (AH05), Ganoderma lucidum (MTCC-1039), and Phanerochaete chrysosporium (MTCC-787) were tested for 3, 6, 9, 12, and 15 days, respectively. G. lucidum achieved the highest degradation efficiency of cyclophosphamide (71.5%) and etoposide (98.4%) after 6 days of treatment. The degradation efficiency of T. versicolor and P. chrysosporium for etoposide was 79.8% and 76.8%, respectively. However, no degradation of cyclophosphamide was achieved with P. chrysosporium, although it showed the highest sorption efficiency for cyclophosphamide (23.7%). Trametes versicolor achieved only 1.4% degradation of cyclophosphamide, that includes both biodegradation and biosorption. The pseudo first-order degradation kinetics explained the degradation of etoposide and cyclophosphamide with t_1/2 values of 1.32 and 4.43 days and 'k' constant of 0.16 and 0.54 day^-1, respectively.

Free and immobilized biocatalysts for removing micropollutants from water and wastewater: Recent progress and challenges

Enzymatic conversion of micropollutants into less-toxic derivatives is an important bioremediation strategy. This paper aims to critically review the progress in water and wastewater treatment by both free and immobilized enzymes presenting this approach as highly efficient and performed under environmentally benign and friendly conditions. The review also summarises the effects of inorganic and organic wastewater matrix constituents on enzymatic activity and degradation efficiency of micropollutants. Finally, application of enzymatic reactors facilitate continuous treatment of wastewater and obtaining of pure final effluents. Of a particular note, enzymatic treatment of micropollutants from wastewater has been mostly reported by laboratory scale studies. Thus, this review also highlights key research gaps of the existing techniques and provides future perspectives to facilitate the transfer of the lab-scale solutions to a larger scale and to improve operationability of biodegradation processes.

Enhanced Efficiency of the Removal of Cytostatic Anthracycline Drugs Using Immobilized Mycelium of Bjerkandera adusta CCBAS 930

The aim of this study was to evaluate the bioremoval of anthracycline antibiotics (daunomycin-DNR, doxorubicin-DOX, and mitoxantrone-MTX) by immobilized mycelium of B. adusta CCBAS 930. The activity of oxidoreductases: versatile peroxidases (VP), superoxide dismutase (SOD), catalase (CAT), and glucose oxidase (GOX), and the levels of phenolic compounds (PhC) and free radicals (SOR) were determined during the biotransformation of anthracyclines by B. adusta strain CCBAS 930. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (MARA assay), and genotoxicity of anthracyclines were evaluated after biological treatment. After 120 h, more than 90% of anthracyclines were removed by the immobilized mycelium of B. adusta CCBAS 930. The effective biotransformation of anthracyclines was correlated with detoxification and reduced genotoxicity.

Protein-stabilized Ir nanoparticles with usual charge-selective peroxidase properties

Selective removal of an organic compound in the coexistence of other constituents is a great challenge in separation and purification processes. In this work, bovine serum albumin (BSA)-stabilized iridium nanoparticles (IrNPs) were prepared via a facile one-step precipitation method. The resulting BSA-IrNPs were comprehensively characterized by TEM, XRD, XPS, UV-vis, FT-IR, and fluorescence spectroscopy as well as circular dichroism spectrometry. It was found that the nanoparticles with an average diameter of 3.6 nm were embedded in the aggregated protein matrix and the structure of the coating agent was maintained well on the surface of nanoparticles. The as-prepared nanozymes (BSA-IrNPs) exhibit strong peroxidase-like activity and can selectively catalyse the degradation of cationic compounds by H₂O₂ in the coexistence of other inorganic or organic substances at room temperature. Interestingly, the degradation of amino acids could be precisely controlled by adjusting the pH above or below their isoelectric points. The catalytic selectivity of BSA-IrNPs should be ascribed to the anchoring effect between the amidogen-containing molecules and BSA through electrostatic adsorption. The nanozyme also exhibits excellent reusability as it can be readily recycled from solution by static settlement or centrifugation. Therefore, BSA-IrNPs have great potential for the selective removal of cationic compounds and amino acids in a complex matrix.

Hospital Wastewater-Source of Specific Micropollutants, Antibiotic-Resistant Microorganisms, Viruses, and Their Elimination

Municipal wastewaters can generally provide real-time information on drug consumption, the incidence of specific diseases, or establish exposure to certain agents and determine some lifestyle consequences. From this point of view, wastewater-based epidemiology represents a modern diagnostic tool for describing the health status of a certain part of the population in a specific region. Hospital wastewater is a complex mixture of pharmaceuticals, illegal drugs, and their metabolites as well as different susceptible and antibiotic-resistant microorganisms, including viruses. Many studies pointed out that wastewater from healthcare facilities (including hospital wastewater), significantly contributes to higher loads of micropollutants, including bacteria and viruses, in municipal wastewater. In addition, such a mixture can increase the selective pressure on bacteria, thus contributing to the development and dissemination of antimicrobial resistance. Because many pharmaceuticals, drugs, and microorganisms can pass through wastewater treatment plants without any significant change in their structure and toxicity and enter surface waters, treatment technologies need to be improved. This short review summarizes the recent knowledge from studies on micropollutants, pathogens, antibiotic-resistant bacteria, and viruses (including SARS-CoV-2) in wastewater from healthcare facilities. It also proposes several possibilities for improving the wastewater treatment process in terms of efficiency as well as economy.

Laccase as an efficacious approach to remove anticancer drugs: A study of doxorubicin degradation, kinetic parameters, and toxicity assessment

The degradation of an anticancer drug by laccase was investigated for the first time, bringing a new approach to treat these hazardous substances through the direct enzymatic application. Degradations of doxorubicin by laccase were performed in different enzymatic concentrations, pH values and temperatures through kinetic studies. The highest enzymatic degradation of doxorubicin was achieved at pH 7 and 30 ºC, which resembles effluent characteristics from wastewater treatment plants. Assays were carried out in different doxorubicin concentrations to comprehend the enzymatic kinetics of degradation. Michaelis-Menten kinetic parameters obtained were maximum velocity obtained (V_max) of 702.8 µg_DOX h^-1 L^-1 and Michaelis-Menten constant (K_M) of 4.05 µM, which showed a good affinity for the substrate. The toxicity was evaluated against L-929 cell line, and the degraded doxorubicin solution did not show a reduction in cell viability in the concentration of 250 µg L^-1. In contrast, the doxorubicin shows a reduction of 27% in cell viability. Furthermore, in the highest tested concentration (1000 µg L^-1), enzymatic degradation reduced in up 41.4% the toxicity of doxorubicin, which indicates laccase degrades doxorubicin to non-toxic compounds. In conclusion, this study provides a new application to laccase since the results showed great potential to remove anticancer drugs from effluents.

Antibiotics in wastewater: From its occurrence to the biological removal by environmentally conscious technologies

In this critical review, we explored the most recent advances about the fate of antibiotics on biological wastewater treatment plants (WWTP). Although the occurrence of these pollutants in wastewater and natural streams has been investigated previously, some recent publications still expose the need to improve the detection strategies and the lack of information about their transformation products. The role of the antibiotic properties and the process operating conditions were also analyzed. The pieces of evidence in the literature associate several molecular properties to the antibiotic removal pathway, like hydrophobicity, chemical structure, and electrostatic interactions. Nonetheless, the influence of operating conditions is still unclear, and solid retention time stands out as a key factor. Additionally, the efficiencies and pathways of antibiotic removals on conventional (activated sludge, membrane bioreactor, anaerobic digestion, and nitrogen removal) and emerging bioprocesses (bioelectrochemical systems, fungi, and enzymes) were assessed, and our concern about potential research gaps was raised. The combination of different bioprocess can efficiently mitigate the impacts generated by these pollutants. Thus, to plan and design a process to remove and mineralize antibiotics from wastewater, all aspects must be addressed, the pollutant and process characteristics and how it is the best way to operate it to reduce the impact of antibiotics in the environment.

White-rot fungi-mediated biodegradation of cytostatic drugs - bleomycin and vincristine

The contamination of the environment with anticancer drugs, which show recalcitrance to conventional wastewater treatment, has become a significant ecological threat. Fungi represent a promising non-conventional biological alternative for water conditioning. The aim of this work was to evaluate the efficacy of five white-rot fungi (Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH) and Trametes versicolor (CB8)) in the removal of bleomycin and vincristine. The removal capacity was measured at 0, 4, 9, and 14 days of incubation using SPE-UPLC-MS. The enzymatic profiles of laccase, manganese, and lignin peroxidases and wide range of eco- and cytotoxicity, assays of the post-process samples were also conducted. We observed >94% vincristine elimination by F. fomentarius, H. fasciculare and T. versicolor after only 4 days. Bleomycin removal occurred after a minimum of 9 days and only when the drug was incubated with T. versicolor (36%) and H. fasciculare (25%). The removal of both cytostatics was associated with laccase production, and the loss of eco- and cytotoxicity, especially in regard to viability of Lemna minor and Daphnia magna, as well as fibroblasts morphology.

Threat and sustainable technological solution for antineoplastic drugs pollution: Review on a persisting global issue

In the past 20 years, the discharge of pharmaceuticals and their presence in the aquatic environment have been continuously increasing and this has caused serious public health and environmental concerns. Antineoplastic drugs are used in chemotherapy, in large quantities worldwide, for the treatment of continuously increasing cancer cases. Antineoplastic drugs also contaminate water sources and possess mutagenic, cytostatic and eco-toxicological effects on microorganisms present in the aquatic environment as well as on human health. Due to the recalcitrant nature of antineoplastic drugs, the commonly used wastewater treatment processes are not able to eliminate these drugs. Globally, various anticancer drugs are being consumed during chemotherapy in hospitals and households by out-patients. These anti-cancer agents enter the water bodies in their original form or as metabolites via urine and faeces of the out-patients or the patients admitted in hospitals. Due to its high lipid solubility, the antineoplastic drugs accumulate in the fatty tissues of the organisms. These drugs enter through the food chain and cause adverse health effects on humans due to their cytotoxic and genotoxic properties. The United States Environmental Protection Agency (US-EPA) and the Organization for Economic Cooperation and Development (OECD) elucidated new regulations for the management of hazardous pharmaceuticals in the water environment. In this paper, the role of antineoplastic agents as emerging water contaminants, its transfer through the food chain, its eco-toxicological properties and effects, technological solutions and management aspects were reviewed.