Degradation of acetaminophen by Delftia tsuruhatensis and Pseudomonas aeruginosa in a membrane bioreactor

The relationship between atmospheric particulate matter, leaf surface microstructure, and the phyllosphere microbial diversity of Ulmus L

BACKGROUND

Plants can retain atmospheric particulate matter (PM) through their unique foliar microstructures, which has a profound impact on the phyllosphere microbial communities. Yet, the underlying mechanisms linking atmospheric particulate matter (PM) retention by foliar microstructures to variations in the phyllosphere microbial communities remain a mystery. In this study, we conducted a field experiment with ten Ulmus lines. A series of analytical techniques, including scanning electron microscopy, atomic force microscopy, and high-throughput amplicon sequencing, were applied to examine the relationship between foliar surface microstructures, PM retention, and phyllosphere microbial diversity of Ulmus L.

RESULTS

We characterized the leaf microstructures across the ten Ulmus lines. Chun exhibited a highly undulated abaxial surface and dense stomatal distribution. Langya and Xingshan possessed dense abaxial trichomes, while Lieye, Zuiweng, and Daguo had sparsely distributed, short abaxial trichomes. Duomai, Qingyun, and Lang were characterized by sparse stomata and flat abaxial surfaces, whereas Jinye had sparsely distributed but extensive stomata. The mean leaf retention values for total suspended particulate (TSP), PM2.5, PM2.5-10, PM10-100, and PM> 100 were 135.76, 6.60, 20.10, 90.98, and 13.08 µg·cm- 2, respectively. Trichomes substantially contributed to PM2.5 retention, while larger undulations enhanced PM2.5-10 retention, as evidenced by positive correlations between PM2.5 and abaxial trichome density and between PM2.5-10 and the adaxial raw microroughness values. Phyllosphere microbial diversity patterns varied among lines, with bacteria dominated by Sediminibacterium and fungi by Mycosphaerella, Alternaria, and Cladosporium. Redundancy analysis confirmed that dense leaf trichomes facilitated the capture of PM2.5-associated fungi, while bacteria were less impacted by PM and struggled to adhere to leaf microstructures. Long and dense trichomes provided ideal microhabitats for retaining PM-borne microbes, as evidenced by positive feedback loops between PM2.5, trichome characteristics, and the relative abundances of microorganisms like Trichoderma and Aspergillus.

CONCLUSIONS

Based on our findings, a three-factor network profile was constructed, which provides a foundation for further exploration into how different plants retain PM through foliar microstructures, thereby impacting phyllosphere microbial communities.

Constructing Heptazine-COF@TiO2 Heterojunction Photocatalysts for Efficient Photodegradation of Acetaminophen under Visible Light

Constructing heterojunction photocatalysts are widely applied to boost the photocatalytic activity of materials. Here, a novel covalent organic framework (COF) material with heptazine units was developed and hybridized with TiO2 nano particles (NPs) to fabricate the Heptazine-COF@TiO2 photocatalysts for acetaminophen (AAP) photodegradation. The successfully assembled heptazine unit endows the Heptazine-COF with outstanding semiconductor property (optical bandgap is 2.53 eV). The synthesized Heptazine-COF@TiO2 hybrids is proved to have the heterojunction structure with high visible light activity and fast charge-carrier mobility, and exhibits better performance in photodegradation of AAP under visible light. The excellent photodegradation efficiency (rate constant: 0.758 min-1) and high reusability (rate constant: 0.452 min-1 in the 6th cycles) of the optimized sample outperform the traditional inorganic photocatalysts and other heterojunction photocatalysts. In addition, these photocatalysts present universal degradation activity for other dyes and antibiotics.

Next-generation hybrid technologies for the treatment of pharmaceutical industry effluents

Water and industries are intangible units of the globe that are always set to meet the population's demand. The global population depends on one-third of freshwater increasing the demand. The increase in population along with urbanization has polluted the fresh water resources. The pharmaceutical industry is marked as an emerging contaminant of water pollution. The most common type of pharmaceutical drugs that are detected in the environment includes antibiotics, analgesics, NSAIDs, and pain-relieving drugs. These drugs alter the food chain of the organisms causing chaos mainly in the marine ecosystem. Pharmaceutical drugs are found only in shallow amounts (ng/mg) they have a huge impact on the living system. The consumption of water contaminated with pharmaceutical ingredients can disrupt reproduction, hormonal imbalance, cancer, and respiratory problems. Various methods are used to remove these chemicals from the environment. In this review, we mainly focused on the emerging hybrid technologies and their significance in the effective treatment of pharmaceutical wastewater. This review paper primarily elaborates on the merits and demerits of existing conventional technologies helpful in developing integrated technologies for the modern era of pharmaceutical effluent treatment. This review paper further in detail discusses the various strategies of eco-friendly bioremediation techniques namely biostimulation, bioaugmentation, bacterial degradation, mycoremediation, phytoremediation, and others for the ultimate removal of pharmaceutical contaminants in wastewater. The review makes clear that targeted and hybrid solutions are what the world will require in the future to get rid of these pharmacological prints.

Distribution and toxicity of dihydroxybenzenes in drinking water sources in Nigeria

This study provides, for the first time, data on the distribution and toxicity of catechol (CAT) and hydroquinone (HQ) in drinking water sources from Africa. Groundwater (boreholes and hand-dug wells) and surface water in three Southwestern States in Nigeria served as sampling sites. The concentrations of CAT and HQ in groundwater and surface water were determined throughout a period of 12 months, evaluating the effects of seasonal variation (rainy and dry seasons). Mean concentrations of CAT in water samples were higher than those of HQ. In this study, CAT was more frequently detected, with its mean concentration in groundwater samples higher in the rainy season (430 μg L-1) than in the dry season (175 μg L-1). Multivariate analysis using the Principal Component Analysis Software suggests that in most sample sites, CAT and HQ in water samples were from entirely different anthropogenic sources. The most impacted population groups were the toddlers and infants. Similarly, maximum and median concentrations of CAT in water samples pose serious risks to Daphnia at both acute and chronic levels. The results from this study suggest the need for further control of these dihydroxybenzenes through regular monitoring and removal from drinking water during treatment.

Simulated-sunlight enhances membrane aerated biofilm reactor performance in sulfamethoxazole removal and antibiotic resistance genes reduction

Membrane aerated biofilm reactors (MABRs) can be used to treat domestic wastewater containing sulfamethoxazole (SMX) because of their favorable performance in the treatment of refractory pollutants. However, biologics are generally subjected to antibiotics stress, which induces the production of antibiotic resistance genes (ARGs). In this study, a simulated-sunlight assisted MABR (L-MABR) was used to promote SMX removal and reduce ARGs production. The SMX removal efficiency of the l-MABR system was 9.62 % superior to that of the MABR system (83.13 %). In contrast from MABR, in the l-MABR, only 28.75 % of SMX was removed through microbial activity because functional bacteria were inactivated through radiation by simulated sunlight. In addition, photolysis (64.61 %) dominated SMX removal, and the best performing indirect photolysis process was the excited state of effluent organic matters (3EfOMs*). Through photolysis, ultraviolet (UV) and reactive oxygen species (ROS) enriched the SMX removal route, resulting in the SMX removal pathway in the l-MABR no longer being limited by enzyme catalysis. More importantly, because of the inactivation of functional bacteria, whether in the effluent or biofilm, the copy number of ARGs in the l-MABR was 1-3 orders of magnitude lower than that in the MABR. Our study demonstrates the feasibility of utilizing simulated-sunlight to enhance the antibiotic removal efficiency while reducing ARG production, thus providing a novel idea for the removal of antibiotics from wastewater.

Thermal Therapy Modulation of the Psoriasis-Associated Skin and Gut Microbiome

INTRODUCTION

Psoriasis is a systemic immune-mediated disease primarily manifesting as skin redness and inflammation. Balneotherapy proved to be a successful non-pharmacological option to reduce the skin areas affected by the disease, but the specific mechanisms underlying this effect have not been elucidated yet. Here we test the hypothesis that the effect of thermal treatments on psoriatic lesions could be partially mediated by changes in the resident microbial population, i.e., the microbiome.

METHODS

In this study, we enrolled patients with psoriasis and monitored changes in their skin and gut microbiome after a 12-bath balneotherapy course with a combination of 16S rRNA amplicon sequencing and metagenomics. Changes in the resident microbiome were then correlated with thermal therapy outcomes evaluated as changes in Psoriasis Area and Severity Index (PASI) and Body Surface Area index (BSA).

RESULTS

The amplicon sequencing analysis of the skin microbiome showed that after thermal treatment the microbiome composition of affected areas improved to approach that typical of unaffected skin. We moreover identified some low-abundance bacterial biomarkers indicative of disease status and treatment efficacy, and we showed via metagenomic sequencing that thermal treatments and thermal water drinking affect the fecal microbiome to host more species associated with favorable metabolic health.

CONCLUSIONS

Changes in lower-abundance microbial taxa presence and abundance could be the basis for the positive effect of thermal water treatment and drinking on the cutaneous and systemic symptomatology of psoriasis.

Isolation and Characterization of the Wastewater Micropollutant Phenacetin-Degrading Bacterium Rhodococcus sp. Strain PNT-23

Phenacetin, an antipyretic and analgesic drug, poses a serious health risk to both humans and aquatic organisms, which is of concern since this micropollutant is frequently detected in various aquatic environments. However, rare pure bacterial cultures have been reported to degrade phenacetin. Therefore, in this study, the novel phenacetin-degrading strain PNT-23 was isolated from municipal wastewater and identified as a Rhodococcus sp. based on its morphology and 16S rRNA gene sequencing. The isolated strain could completely degrade 100 mg/L phenacetin at an inoculum concentration of OD600 1.5 within 80 h, utilizing the micropollutant as its sole carbon source for growth. Strain PNT-23 exhibited optimal growth in LB medium at 37 °C and a pH of 7.0 with 1% NaCl, while the optimal degradation conditions in minimal medium were 30 °C and a pH of 7.0 with 1% NaCl. Two key intermediates were identified during phenacetin biodegradation by the strain PNT-23: N-acetyl-4-aminophenol and 4-aminophenol. This study provides novel insights into the biodegradation of phenacetin using a pure bacterium culture, expands the known substrate spectra of Rhodococcus strains and presents a potential new candidate for the microbial removal of phenacetin in a diverse range of environments.

Photocatalytic Degradation of Acetaminophen in Aqueous Environments: A Mini Review

Over the past few decades, acetaminophen (ACT), a typical nonsteroidal anti-inflammatory drug (NSAID), has gained global usage, positioning itself as one of the most extensively consumed medications. However, the incomplete metabolism of ACT leads to a substantial discharge into the environment, classifying it as an environmental contaminant with detrimental effects on non-target organisms. Various wastewater treatment technologies have been developed for ACT removal to mitigate its potential environmental risk. Particularly, photocatalytic technology has garnered significant attention as it exhibits high efficiency in oxidizing and degrading a wide range of organic pollutants. This comprehensive review aims to systematically examine and discuss the application of photocatalytic technology for the removal of ACT from aqueous environments. Additionally, the study provides a detailed overview of the limitations associated with the photocatalytic degradation of ACT in practical applications, along with effective strategies to address these challenges.

Unravelling ciprofloxacin removal in a nitrifying moving bed biofilm reactor: Biodegradation mechanisms and pathways

Although moving bed biofilm reactors (MBBRs) have shown excellent antibiotic removal potentials, the information on underlying mechanisms is yet limited. This work assessed the removal of ciprofloxacin in an enriched nitrifying MBBR by clarifying the contribution of adsorption and microbial-induced biodegradation. Results demonstrated the considerable biomass adsorption (55%) in first 30 min. Limiting nitrite oxidizing bacteria growth or inhibiting nitrification would lead to lower adsorption capacities. The highest ciprofloxacin biodegradation rate constant was 0.082 L g SS^-1 h^-1 in the presence of ammonium, owing to ammonia oxidizing bacteria (AOB)-induced cometabolism, while heterotrophs played an insignificant role (∼9%) in ciprofloxacin biodegradation. The developed model also suggested the importance of AOB-induced cometabolism and metabolism over heterotrophs-induced biodegradation by analyzing the respective biodegradation coefficients. Cometabolic biodegradation pathways of ciprofloxacin mainly involved the piperazine ring cleavage, probably alleviating antimicrobial activities. It implies the feasibility of nitrifying biofilm systems towards efficient antibiotic removal from wastewater.

Advances of non-thermal plasma discharge technology in degrading recalcitrant wastewater pollutants. A comprehensive review

With development and urbanization, the amount of wastewater generated due to human activities drastically increases yearly, causing water pollution and intensifying the already worsened water crisis. Although convenient, conventional wastewater treatment methods such as activated sludge, stabilization ponds, and adsorption techniques cannot fully eradicate the complex and recalcitrant contaminants leading to toxic byproducts generation. Recent advancements in wastewater treatment techniques, specifically non-thermal plasma technology, have been extensively investigated for the degradation of complex pollutants in wastewater. Non-thermal plasma is an effective alternative for degrading and augmenting the biodegradability of recalcitrant pollutants due to its ability to generate reactive species in situ. This article critically reviews the non-thermal plasma technology, considering the plasma discharge configuration and reactor types. Furthermore, the influence of operational parameters on the efficiency of the plasma systems and the reactive species generated by the system during discharge has gained significant interest and hence been discussed. Also, the application of non-thermal plasma technology for the degradation of pharmaceuticals, pesticides, and dyes and the inactivation of microbial activities are outlined in this review article. Additionally, optimistic applications involving the combination of non-thermal plasma and catalysts and pilot and industrial-scale projects utilizing non-thermal plasma technology have been addressed. Concluding perceptions on the challenges and future perspectives of the non-thermal technology on wastewater treatment are accentuated. Overall, this review outlines a comprehensive understanding of the non-thermal plasma technology for recalcitrant pollutant degradation from a scientific perspective providing detailed instances for reference.

Transcriptomic Analysis of Acetaminophen Biodegradation by Penicillium chrysogenum var. halophenolicum and Insights into Energy and Stress Response Pathways

(1) Background: Acetaminophen (APAP), an active component of many analgesic and antipyretic drugs, is one of the most concerning trace contaminants in the environment and is considered as an emergent pollutant of marine and aquatic ecosystems. Despite its biodegradability, APAP has become a recalcitrant compound due to the growth of the global population, the ease of availability, and the inefficient wastewater treatment applied. (2) Methods: In this study, we used a transcriptomic approach to obtain functional and metabolic insights about the metabolization of APAP by a phenol-degrading fungal strain, Penicillium chrysogenum var. halophenolicum. (3) Results: We determined that the transcriptomic profile exhibited by the fungal strain during APAP degradation was very dynamic, being characterized by an abundance of dysregulated transcripts which were proportional to the drug metabolization. Using a systems biology approach, we also inferred the protein functional interaction networks that could be related to APAP degradation. We proposed the involvement of intracellular and extracellular enzymes, such as amidases, cytochrome P450, laccases, and extradiol-dioxygenases, among others. (4) Conclusions: Our data suggested that the fungus could metabolize APAP via a complex metabolic pathway, generating nontoxic metabolites, which demonstrated its potential in the bioremediation of this drug.

Characterization and biodegradation of paracetamol by biomass of Bacillus licheniformis strain PPY-2 isolated from wastewater

Industrialization leads to the entry of diverse xenobiotic compounds into the environment. One such compound is paracetamol (APAP), which is emerging as a pharmaceutical and personal care pollutant (PPCP). In this study, the APAP degrading bacterium was isolated by enrichment culture method from the sewage sample. The microscopy, biochemical, and 16S rRNA gene sequence analyzed the isolate PPY-2, which belongs to Bacillus licheniformis, and GenBank assigned accession number MN744328. Physiological and batch culture degradation studies have indicated that the strain involved in the degradation of APAP. The optimum pH for degradation of the PPY-2 was 7.7, whereas the temperature was 25 °C, agitation speed was 142 rpm, and concentration of APAP was 621 mg/L reported, and the optimum temperatures were 42 °C and 32 °C, respectively. Biomass kinetic was studied at optimal physical conditions, which suggested that the specific growth rate (μ) was 721 mg/L. The GC-MS chromatogram peaks have detected metabolites, viz., oxalic acid, 2-isopropyl-5-methyl cyclohexanone, and phenothiazine. The study confirmed that Bacillus licheniformis strain PPY-2 exhibits metabolic potential to biodegradation APAP and can be further deployed in bioremediation.

Isolation of Novel Bacterial Strains Pseudomonas extremaustralis CSW01 and Stutzerimonas stutzeri CSW02 from Sewage Sludge for Paracetamol Biodegradation

Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground waters, sediments, soils or even plants, where it is introduced mainly from the discharge of wastewater and the use of sewage sludge as fertilizer in agriculture. Its accumulation in certain organisms can induce reproductive, neurotoxic or endocrine disorders, being therefore considered an emerging pollutant. This study reports on the isolation, from sewage sludge produced in wastewater treatment plants (WWTPs), of bacterial strains capable of degrading paracetamol. Up to 17 bacterial strains were isolated, but only two of them, identified as Pseudomonas stutzeri CSW02 and Pseudomonas extremaustralis CSW01, were able to degrade very high concentrations of paracetamol in solution as a sole carbon and energy source, and none of them had been previously described as paracetamol degraders. These bacteria showed the ability to degrade up to 500 mg L^-1 of paracetamol in only 6 and 4 h, respectively, much quicker than any other paracetamol-degrader strain described in the literature. The two main paracetamol metabolites, 4-aminophenol and hydroquinone, which present high toxicity, were detected during the degradation process, although they disappeared very quickly for paracetamol concentrations up to 500 mg L^-1. The IC₅₀ of paracetamol for the growth of these two isolates was also calculated, indicating that P. extremaustralis CSW01 was more tolerant than S. stutzeri CSW02 to high concentrations of paracetamol and/or its metabolites in solution, and this is the reason for the much lower paracetamol degradation by S. stutzeri CSW02 at 2000-3000 mg L^-1. These findings indicate that both bacteria are very promising candidates for their use in paracetamol bioremediation in water and sewage sludge.

Microbial paracetamol degradation involves a high diversity of novel amidase enzyme candidates

Pharmaceuticals are relatively new to nature and often not completely removed in wastewater treatment plants (WWTPs). Consequently, these micropollutants end up in water bodies all around the world posing a great environmental risk. One exception to this recalcitrant conversion is paracetamol, whose full degradation has been linked to several microorganisms. However, the genes and corresponding proteins involved in microbial paracetamol degradation are still elusive. In order to improve our knowledge of the microbial paracetamol degradation pathway, we inoculated a bioreactor with sludge of a hospital WWTP (Pharmafilter, Delft, NL) and fed it with paracetamol as the sole carbon source. Paracetamol was fully degraded without any lag phase and the enriched microbial community was investigated by metagenomic and metatranscriptomic analyses, which demonstrated that the microbial community was very diverse. Dilution and plating on paracetamol-amended agar plates yielded two Pseudomonas sp. isolates: a fast-growing Pseudomonas sp. that degraded 200 mg/L of paracetamol in approximately 10 h while excreting 4-aminophenol, and a slow-growing Pseudomonas sp. that degraded paracetamol without obvious intermediates in more than 90 days. Each Pseudomonas sp. contained a different highly-expressed amidase (31% identity to each other). These amidase genes were not detected in the bioreactor metagenome suggesting that other as-yet uncharacterized amidases may be responsible for the first biodegradation step of paracetamol. Uncharacterized deaminase genes and genes encoding dioxygenase enzymes involved in the catabolism of aromatic compounds and amino acids were the most likely candidates responsible for the degradation of paracetamol intermediates based on their high expression levels in the bioreactor metagenome and the Pseudomonas spp. genomes. Furthermore, cross-feeding between different community members might have occurred to efficiently degrade paracetamol and its intermediates in the bioreactor. This study increases our knowledge about the ongoing microbial evolution towards biodegradation of pharmaceuticals and points to a large diversity of (amidase) enzymes that are likely involved in paracetamol metabolism in WWTPs.

A review on synergistic coexisting pollutants for efficient photocatalytic reaction in wastewater remediation

With the tremendous development of the economy and industry, the pollution of water is becoming more serious due to the excessive chemical wastes that need to remove thru reduction or oxidation reactions. Simultaneous removal of dual pollutants via photocatalytic redox reaction has been tremendously explored in the last five years due to effective decontamination of pollutants compared to a single pollutants system. In a photocatalysis mechanism, the holes in the valence band can remarkably promote the oxidation of a pollutant. At the same time, photoexcited electrons are also consumed for the reduction reaction. The synergistic between the reduction and oxidation inhibits the recombination of electron-hole pairs extending their lifetime. In this review, the binary pollutants that selectively removed via photocatalysis reduction or oxidation are classified according to heavy metal-organic pollutant (HM/OP), heavy metal-heavy metal (HM/HM) and organic-organic pollutants (OP/OP). The intrinsic between the pollutants was explained in three different mechanisms including inhibition of electron-hole recombination, ligand to metal charge transfer and electrostatic attraction. Several strategies for the enhancement of this treatment method which are designation of catalysts, pH of mixed pollutants and addition of additive were discussed. This review offers a recent perspective on the development of photocatalysis system for industrial applications.

Potential for Natural Attenuation of Domestic and Agricultural Pollution in Karst Groundwater Environments

In karst areas, anthropogenic contaminants reach the subsurface with detrimental effects on the groundwater ecosystem and downstream springs, which often serve as drinking water sources for the local human communities. We analyzed the water chemistry and microbial community composition in upstream and downstream locations of five hydrokarst systems (HKS) during four seasons. Conductivity and nitrates were higher in the downstream springs than in the pre-karst waters, whereas the concentration of organic matter, considered here as a pollution indicator, was lower. The microbial community composition varied largely between upstream and downstream locations, with multiple species of potentially pathogenic bacteria decreasing in the HKS. Bacteria indicative of pollution decreased as well when passing through the HKS, but potential biodegraders increased. This suggests that the HKS can filter out part of the polluting organic matter and, with it, part of the associated microorganisms. Nevertheless, the water quality, including the presence of pathogens in downstream springs, must be further monitored to control whether the water is appropriate for consumption. In parallel, the human populations located upstream must be advised of the risks resulting from their daily activities, improper stocking of their various wastes and dumping of their refuse in surface streams.

Pharmaceutical Pollution in Aquatic Environments: A Concise Review of Environmental Impacts and Bioremediation Systems

The presence of emerging contaminants in the environment, such as pharmaceuticals, is a growing global concern. The excessive use of medication globally, together with the recalcitrance of pharmaceuticals in traditional wastewater treatment systems, has caused these compounds to present a severe environmental problem. In recent years, the increase in their availability, access and use of drugs has caused concentrations in water bodies to rise substantially. Considered as emerging contaminants, pharmaceuticals represent a challenge in the field of environmental remediation; therefore, alternative add-on systems for traditional wastewater treatment plants are continuously being developed to mitigate their impact and reduce their effects on the environment and human health. In this review, we describe the current status and impact of pharmaceutical compounds as emerging contaminants, focusing on their presence in water bodies, and analyzing the development of bioremediation systems, especially mycoremediation, for the removal of these pharmaceutical compounds with a special focus on fungal technologies.

Isolation and identification of acetaminophen degrading strain Shinella sp. HZA2

Acetaminophen (APP), frequently used as analgesic and antipyretic drug in our life, is potentially toxic to both animals and humans. A novel acetaminophen degrading strain HZA2, was isolated from the activated sludge, and identified as Shinella sp. based on its 16S rRNA gene sequence analysis, morphological, physiological, and biochemical characterizations. This strain could degrade 100 mg L^-1 acetaminophen completely within 12 h, and it was also a very effective strain for the degradation of high concentration of acetaminophen below 3000 mg L^-1 under the optimal condition. The optimal degrading conditions of acetaminophen by HZA2 were pH 7.5 and 32.7 °C by the analysis of response surface methodology. Exogenous carbon source could enhance the biodegradation of acetaminophen. During the process, the intermediate metabolites were identified as 4-aminophenol and hydroquinone via gas chromatography-mass spectrometry analysis. The results indicated that strain HZA2 may be a promising bacterium for the bioremediation of acetaminophen pollutions.

In-situ fabrication of polypyrrole composite with MoO3: An effective interfacial charge transfers and electrode materials for degradation and determination of acetaminophen

Pharmaceutical wastes, acetaminophen (AP) widely used in medical fields, is often discharged into water, causing harm to human health. Hence, there is an urgent need to effectively remove AP from wastewater systems. In this paper, polypyrrole (PPy) composite with MoO₃ has been synthesized via an in-situ polymerization method. The as-prepared materials were thoroughly characterized by XRD, FT-IR, UV-DRS, SEM, TEM and mapping techniques. The as-prepared MoO₃@PPy composite was utilized to removal of AP via photocatalytic degradation and electrochemical determination. Under optimized composite, MoO₃@PPy (2) showed an excellent photocatalytic degradation and electrochemical determination of AP compared to pure MoO₃ and all other composites. The higher catalytic activity was ascribed to the effective interfacial charges transfer, reduce the recombination and enhance the active surface area of electrode via a synergistic effect. The photocatalytic degradation mechanism, rate and kinetic of the reaction were investigated and discussed. The major active degradation species and an effective charge transfer properties were confirmed by trapping experiments and photocurrent spectra. In addition, the MoO₃@PPy (2) modified GCE exhibit the AP determination activity by DPV with a linear range of 0.05-546 μM. The limit of detection and sensitivity of electrode were 0.0007 μM and 0.242 μM^-1 cm^-2 respectively. Moreover, the proposed electrode showed good selectivity, stability and reproducibility. This method was useful for the determination of AP in real samples.

Constructed and Floating Wetlands for Sustainable Water Reclamation

Modern urbanized societies are facing serious challenges in the maintenance of their water resources [...]

Medicines as an emergent contaminant: the review of microbial biodegration potential

Emerging environmental contaminants, such as medicine waste, are of great concern to the scientific community and to the local environmental and health departments because of their potential long-term effects and ecotoxicological risk. Besides the prolonged use of medicines for the development of modern society, the elucidation of their effect on the ecosystem is relatively recent. Medicine waste and its metabolites can, for instance, cause alterations in microbial dynamics and disturb fish behavior. Bioremediation is an efficient and eco-friendly technology that appears as a suitable alternative to conventional methods of water waste and sludge treatment and has the capacity to remove or reduce the presence of emerging contaminants. Thus, this review has the objective of compiling information on environmental contamination by common medicines and their microbial biodegradation, focusing on five therapeutic classes: analgesics, antibiotics, antidepressants, non-steroidal anti-inflammatory drugs (NSAIDs), and contraceptives. Their effects in the environment will also be analyzed, as well as the possible routes of degradation by microorganisms.

Do initial concentration and activated sludge seasonality affect pharmaceutical biotransformation rate constants?

Pharmaceuticals find their way to the aquatic environment via wastewater treatment plants (WWTPs). Biotransformation plays an important role in mitigating environmental risks; however, a mechanistic understanding of involved processes is limited. The aim of this study was to evaluate potential relationships between first-order biotransformation rate constants (k_b) of nine pharmaceuticals and initial concentration of the selected compounds, and sampling season of the used activated sludge inocula. Four-day bottle experiments were performed with activated sludge from WWTP Groesbeek (The Netherlands) of two different seasons, summer and winter, spiked with two environmentally relevant concentrations (3 and 30 nM) of pharmaceuticals. Concentrations of the compounds were measured by LC-MS/MS, microbial community composition was assessed by 16S rRNA gene amplicon sequencing, and k_b values were calculated. The biodegradable pharmaceuticals were acetaminophen, metformin, metoprolol, terbutaline, and phenazone (ranked from high to low biotransformation rates). Carbamazepine, diatrizoic acid, diclofenac, and fluoxetine were not converted. Summer and winter inocula did not show significant differences in microbial community composition, but resulted in a slightly different k_b for some pharmaceuticals. Likely microbial activity was responsible instead of community composition. In the same inoculum, different k_b values were measured, depending on initial concentration. In general, biodegradable compounds had a higher k_b when the initial concentration was higher. This demonstrates that Michealis-Menten kinetic theory has shortcomings for some pharmaceuticals at low, environmentally relevant concentrations and that the pharmaceutical concentration should be taken into account when measuring the k_b in order to reliably predict the fate of pharmaceuticals in the WWTP. KEY POINTS: • Biotransformation and sorption of pharmaceuticals were assessed in activated sludge. • Higher initial concentrations resulted in higher biotransformation rate constants for biodegradable pharmaceuticals. • Summer and winter inocula produced slightly different biotransformation rate constants although microbial community composition did not significantly change.

Biodegradation of Paracetamol by Some Gram-Positive Bacterial Isolates

Bacterial isolates with the capacity to remove paracetamol were selected from an activated sludge sample collected in an oxidation ditch of a wastewater treatment plant. Among these, twelve bacterial isolates were selected according to their capacity to grow in the presence of paracetamol. They were identified using the colony morphotype procedure and by 16S rRNA gene sequencing analysis, but only four of them showed the ability to utilise paracetamol as the sole carbon source in the presence of a nitrogen supply. Those four bacterial isolates were assigned to species of the genera Bacillus, [Brevibacterium], Corynebacterium and Enterococcus. Bacterial isolates were cultured in liquid mineral salt medium (MSM) spiked with 200 mg/L of paracetamol at 28 °C in the dark. In cultures inoculated with [Brevibacterium] frigoritolerans, Corynebacterium nuruki and Enterococcus faecium, removal of 97 ± 4%, 97 ± 6% and 86.9 ± 0.8% of paracetamol at 200 mg/L were obtained, respectively, while in the presence of a species belonging to Bacillus cereus group removal of the drug below the limits of detection was attained with evidence of mineralisation, after 144 h of incubation. During the degradation process, the metabolites 4-aminophenol, hydroquinone and 2-hexenoic acid were detected. As far as we know, these species are herein first-time described as paracetamol degraders.

Photocatalytic and biodegradation treatments of paracetamol: investigation of the in vivo toxicity

Medicines and drugs consumption by all populations of the world can be expected to result in the contamination of the environment since 30-90% of residual drugs will be found into wastewaters. In this study, we investigate the degradation of acetaminophen, selected as a xenobiotic model molecule, via two separate procedures, the TiO₂ impregnated on cellulosic paper photocatalysis, and specific bacterial biodegradation process. Results showed that for initial drug content of 400 mg/L and after 5 hours of processing, around 85% of paracetamol was photocatalytically degraded. The use of Pseudomonas putida E1.21 isolate allowed an abatement of around 92% after 32 h of processing. The acetaminophen toxicity conducted in vivo on laboratory mice showed a net decrease of the creatinine release and enzymes activities like ALP, ALT, AST, and LDH decreased significantly (p < 0.05) when mice were treated distinctly by acetaminophen treated with UV/TiO₂ and the Pseudomonas putida E1.21 strain compared with the control experiments. CAT, MDA, and AchE serum level disruption measurement indicated a serious affection of the mice antioxidant system. These results were found to be in correlation with the ones of the histological analysis of the liver and kidney.

Removal of pharmaceutical and personal care products (PPCPs) from wastewater using microalgae: A review

Pharmaceuticals and personal care products (PPCPs) are a group of emerging micro-pollutants causing detrimental effects on living organisms even at low doses. Previous investigations have confirmed the presence of PPCPs in the environment at hazardous levels, mainly due to the inefficiency of conventional wastewater treatment plants (CWWTPs). Their stable structure induces longer persistence in the environment. Microalgae are currently used to bioremediate numerous pollutants of different characteristics and properties released from the domestic, industrial, agricultural, and farm sectors. CO₂ mitigation during culture and the use of biomass as feedstock for biodiesel or biofuel production are, briefly, other benefits of microalgae-mediated treatment over CWWTPs. This review provides a comprehensive summary of recent literature, an overview of approaches and treatment systems, and breakthrough in the field of algal-mediated removal of PPCPs in wastewater treatment processes. The mechanisms involved in phycoremediation, along with their experimental approaches, have been discussed in detail. Factors influencing the removal of PPCPs from aqueous media are comprehensively described and assessed. A comparative study on microalgal strains is analyzed for a more efficient implementation of future processes. The role of microalgae to mitigate the most severe environmental impacts of PPCPs and the generation of antibiotic-resistant bacteria is discussed. Also, a detailed assessment of recent research on potential toxic effects of PPCPs on microalgae was conducted. The current review highlights microalgae as a promising and sustainable approach to efficiently bio-transform or bio-adsorb PPCPs.

Effect of Pseudomonas moorei KB4 Cells' Immobilisation on Their Degradation Potential and Tolerance towards Paracetamol

Pseudomonas moorei KB4 is capable of degrading paracetamol, but high concentrations of this drug may cause an accumulation of toxic metabolites. It is known that immobilisation can have a protective effect on bacterial cells; therefore, the toxicity and degradation rate of paracetamol by the immobilised strain KB4 were assessed. Strain KB4 was immobilised on a plant sponge. A toxicity assessment was performed by measuring the concentration of ATP using the colony-forming unit (CFU) method. The kinetic parameters of paracetamol degradation were estimated using the Hill equation. Toxicity analysis showed a protective effect of the carrier at low concentrations of paracetamol. Moreover, a pronounced phenomenon of hormesis was observed in the immobilised systems. The obtained kinetic parameters and the course of the kinetic curves clearly indicate a decrease in the degradation activity of cells after their immobilisation. There was a delay in degradation in the systems with free cells without glucose and immobilised cells with glucose. However, it was demonstrated that the immobilised systems can degrade at least ten succeeding cycles of 20 mg/L paracetamol degradation. The obtained results indicate that the immobilised strain may become a useful tool in the process of paracetamol degradation.

A review of the biotransformations of priority pharmaceuticals in biological wastewater treatment processes

Wastewater effluent discharges have been considered as one of the main sources of synthetic chemicals entering into the aquatic environment. Even though they occur at low concentrations, pharmaceutically active compounds (PhACs) can have an impact on ecological toxicity that affects aquatic organisms. Moreover, new regulations in development toward preserving water quality reinforces the increasing need to monitor and abate some PhACs in wastewater treatment plants (WWTPs), where they are typically only partially eliminated. Unlike most previous reviews, we have focussed on how the main biological and chemical molecular factors impact the biotransformations of key PhACs in biological WWTP processes. Biotransformations have been found to be an important contributor towards the removal of PhACs from WWTP effluents. This review paper critically assesses these aspects and the recent advances that have been achieved in wastewater treatment processes for biodegradation of 7 PhACs; namely the non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF); the macrolide antibiotics azithromycin (AZM), erythromycin (ERY) and clarithromycin (CLR); the two natural estrogens estrone (E1) and 17β-estradiol (E2), and the synthetic estrogen 17α-ethinylesradiol (EE2). These represent the micropollutants of the EU Watch list in Decision 2015/495/EU that are most relevant to WWTPs due to their frequent detection. The metabolic pathways, transformation products and impact of relevant factors to biological WWTP processes is addressed in this review. The biokinetics of PhAC biodegradation in different engineered bioprocesses is also discussed. Promising technologies and operational strategies that are likely to have a high impact on controlling PhAC releases are highlighted and future research needs are also proposed.

Enhanced removal of cephalexin and sulfadiazine in nitrifying membrane-aerated biofilm reactors

Nitrification process has been reported to be capable of degrading various pharmaceuticals due to the cometabolism of ammonia-oxidizing bacteria (AOB). The membrane aerated biofilm reactor (MABR) is an emerging configuration in wastewater treatment with advantages of high nitrification rate and low energy consumption. However, there are very few studies investigating the degradation of antibiotics at environmentally relevant levels in nitrifying MABR systems. In this study, the removal of two widely used antibiotics, cephalexin (CFX) and sulfadiazine (SDZ), was evaluated in two independent MABRs with nitrifying biofilms. The impacts of CFX and SDZ exposure on the nitrification performance and microbial community structure within biofilms were also investigated. The results showed that nitrifying biofilms were very efficient in removing CFX (94.6%) and SDZ (75.4%) with an initial concentration of 100 μg/L when hydraulic retention time (HRT) was 4 h in the reactors. When HRT decreased from 4 h to 3 h, the removal rates of CFX and SDZ increased significantly from 23.4 ± 1.0 μg/(L·h) and 18.7 ± 1.1 μg/(L·h), respectively, to 27.7 ± 1.3 μg/(L·h) (p＜0.01) and 20.8 ± 2.4 μg/(L·h) (p＜0.05), while the removal efficiencies decreased to 86.0% and 61.5%, respectively. Despite the exposure to CFX and SDZ, the nitrification performance was not affected, and microbial community structure within biofilms also remained relatively stable. This study shows that nitrifying MABR process is a promising option for the efficient removal of antibiotics from domestic wastewater.

Detoxification and bioaugmentation potential for acetaminophen and its derivatives using Ensifer sp. isolated from activated sludge

Acetaminophen (APAP), a widely used analgesic-antipyretic drug, is frequently detected in the environment and may pose ecological risks to aquatic communities. In this work, an APAP-degrading organism, designated as Ensifer sp. POKHU, was isolated from activated sludge (AS) enriched with APAP. POKHU degraded up to 630 mg/L of APAP without substrate inhibition. The bacterium metabolized APAP to hydroquinone (HQ) via 4-aminophenol (4-AP). APAP derivatives, 4AP, HQ, and 1,4-benzoquinone (BQ), frequently detected in the environment, were found to inhibit nitrogen metabolism (ammonium oxidation) to a greater extent than APAP. POKHU had the ability to degrade varying levels (0.4-40 mg/L) of 4-AP, HQ, and BQ, which indicated a great potential for detoxification in environments contaminated with both APAP and its derivatives. The addition of POKHU to fresh AS samples taken from a wastewater treatment plant greatly increased the biotransformation rates of APAP from 5.6 d^-1 (no POKHU augmentation) to >20.0 d^-1 (5% POKHU). Bioaugmentation with POKHU reduced 400 μg/L of APAP to levels below its ecotoxicity threshold within 4 h, which is shorter than the typical hydraulic retention times for full-scale AS processing. Overall, this study identified a new auxiliary biological agent for APAP detoxification, which could degrade both APAP and its metabolic derivatives (those that can be more toxic than the parent contaminant, APAP). The results have practical implications for developing a biological means (detoxification and bioaugmentation) of treating high-strength pharmaceutical waste streams, such as wastewater from hospitals and drug manufactures, and of landfill leachates.

Activated sludge-degrading analgesic drug acetaminophen: Acclimation, microbial community dynamics, degradation characteristics, and bioaugmentation potential

This study identified specific bacterial populations that play a key role in detoxifying acetaminophen (N-acetyl-p-aminophenol, APAP) in activated sludge (AS) microbial communities. An AS bioreactor was established by feeding 100 mg/L of APAP as a sole carbon, nitrogen, and energy source. While the bioreactor increased APAP biotransformation rates significantly (0.7 d^-1 to 6.1 d^-1) over a month of acclimation, it selected for Pseudomonas by significantly reducing community diversity by 40% and richness by 47%. A Pseudomonas population (designated PCO) isolated from the APAP-degrading community was phylogenetically distinct from other Pseudomonas spp. previously reported as APAP-degrading isolates. PCO could remove APAP at levels up to 590 mg/L without inhibition and could also metabolize APAP-derived metabolites, 4-aminophenol, hydroquinone, and 1,4-benzoquinone at varying levels. PCO was introduced to AS at various volumes (5, 25, and 50% of the total), showing significantly enhanced APAP transformation rates (1.5, 1.9, and 2.3 d^-1) compared to the control (1.2 d^-1) without PCO inoculation. Overall, our study provides new insights into the phylogenetic and metabolic features of a key species population predominantly accelerating APAP breakdown in the context of AS microbial communities, which will help in the design of a biological means (bioaugmentation) of treating APAP-bearing waste streams.

Biodegradation and Kinetic Analysis of Acetaminophen with Co-culture of Bacterial Strains Isolated from Sewage Wastewater

Acetaminophen (paracetamol, APAP) is one of the fastest growing pharmaceutical pollutants in the environment and has been classified under among the emerging organic pollutants (EOPs). The increasing concentration of it in our environment is not only harmful to the ecosystem, but also to the humans as well. In this study, the microscopy, biochemical test and 16S rRNA sequencing the characterization of APAP as the sole degrading stains viz. Staphylococcus sciuri strain DPP1 (MN744326), Bacillus subtilis strain DPP3 (MN744327), Bacillus paralicheniformis strain DKP1 (MN744324), Enterococcus faecium strain DKP2 (MN744325) and DDP2 (MT705211) were performed. Haldane's growth kinetic model was used to identify specific growth rate and observed for DPP1 (485 mg/L), DPP3 (593 mg/L), DKP1 (477 mg/L), DKP2 (702 mg/L) and DDP2 (685 mg/L). The maximum specific growth rate was reported for the stains viz. DPP1, DPP3, DKP1, DKP2, and DDP2, was in order of 0.076, 0.223, 0.259, 0.179, and 0.141, respectively. The Box-Behnken Design (BBD) was used to identify the effect of physical parameters on degradation using mathematical modeling. The analysis of variance (ANOVA) showed that the strains DPP1, DPP3, DKP1, DKP2, and DDP2 had significant F-value and regression coefficient (R²) value of 0.01%, 0.06%, 0.37%, and 0.18%, respectively. The co-culture of the five strains has utilized 1200 mg/L of APAP within 70 h while individual strains took 10 days. The intermediate metabolites like 4-aminophenol, benzamide, (R)-2-methylpentanoic acid, methylene-3-vinyl cyclohexane, and 1,5-hexadiene were identified by GC-MS. The degradation metabolic pathway was predicted by the intermediates by GC-MS, and PathPred based analysis.

Microbial Communities Associated with Acetaminophen Biodegradation from Mangrove Sediment

Acetaminophen (ACE) is a widely used medicine. Currently, concerns regarding its potential adverse effects on the environments are raised. The aim of this study was to evaluate ACE biodegradation in mangrove sediments under aerobic and anaerobic conditions. Three ACE biodegradation strategies in mangrove sediments were tested. The degradation half-lives (t1/2) of ACE in the sediments with spent mushroom compost under aerobic conditions ranged from 3.24 ± 0.16 to 6.25 ± 0.31 d. The degradation half-lives (t1/2) of ACE in sediments with isolated bacterial strains ranged from 2.54 ± 0.13 to 3.30 ± 0.17 d and from 2.62 ± 0.13 to 3.52 ± 0.17 d under aerobic and anaerobic conditions, respectively. The degradation half-lives (t1/2) of ACE in sediments amended with NaNO3, Na2SO4 and NaHCO3 under anaerobic conditions ranged from 1.16 ± 0.06 to 3.05 ± 0.15 d, 2.39 ± 0.12 to 3.84 ± 0.19 d and 2.79 ± 0.14 to 10.75 ± 0.53 d, respectively. The addition of the three electron acceptors enhanced ACE degradation in mangrove sediments, where NaNO3 yielded the best effects. Sixteen microbial genera were identified as the major members of microbial communities associated in anaerobic ACE degradation in mangrove sediments with addition of NaNO3 and Na2SO4. Three (Arthrobacter, Enterobacter and Bacillus) of the sixteen microbial genera were identified in the isolated ACE-degrading bacterial strains.

Effects of Low Concentration of Selected Analgesics and Successive Bioaugmentation of the Activated Sludge on Its Activity and Metabolic Diversity

In this study, we evaluated the impact of the successive bioaugmentation of the activated sludge (AS) with the defined bacterial consortium on the activity and functional capacity of the AS microorganisms. In parallel, the removal of low concentrations of the selected non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac) and analgesic paracetamol was studied. We found that the addition of the bacterial consortium consisting of three pharmaceuticals-degrading strains Bacillus thuringiensis B1 (2015b), Stenotrophomonas maltophilia KB2, and Pseudomonas moorei KB4 into the AS did not cause any significant changes in the biomass abundance and metabolic activity of the AS microorganisms. Although, the successive bioaugmentation of the AS caused a slight increase in the metabolic diversity, the intensity of carbohydrates usage, and metabolic richness. Microorganisms in the bioaugmented and non-bioaugmented AS were able to degrade the mixture of the analyzed drugs with similar efficiency, however, diclofenac was removed more effectively in the bioaugmented AS. Several metabolites were identified and efficiently utilized, with the exception of 4-OH diclofenac. Two new diclofenac-degrading strains assigned as Serratia proteamaculans AS4 and Rahnella bruchi AS7 were isolated from the diclofenac-treated AS.

Characterization, optimization and kinetics study of acetaminophen degradation by Bacillus drentensis strain S1 and waste water degradation analysis

Background

In this study, the biodegradation of N-acetyl-para-aminophenol also known as acetaminophen (APAP, paracetamol) was studied by bacterial strain Bacillus drentensis strain S1 (accession no. KY623719) isolated from sewage sample.

Results

The Bacillus drentensis strain S1 was isolated from the sewage sample using the enrichment culture method. As per our knowledge this is the first Bacillus drentensis strain reported for the degradation of APAP. In this study a 20-L batch reactor was employed for degradation of APAP. The maximum specific growth rate (μmax) was observed at 400 mg/L concentration of APAP. The pilot-scale anaerobic batch reactor of was stable and self-buffered. The degradation in pilot-scale reactor was slow as compared to batch experiments due to fluctuation in pH and exhaustion of nutrients. Design-Expert® software was used for optimization of conditions for APAP degradation; such as temperature (40 °C), pH (7.0), concentration of APAP (300 g/L) and agitation speed (165 rpm). The FTIR and GC–MS were used to identify the degradation metabolites. The intermediates of degradation like 2-isopropyl-5-methylcyclohexanone and phenothiazine were observed, based on these results the metabolic pathway has been predicted.

Conclusions

The optimization, kinetic, batch study and pilot study indicates the potential of Bacillus drentensis strain S1 for degradation of acetaminophen. The experimental design, optimization and statistical analysis were performed by Design Expert® software. The optimal growth condition for Bacillus drentensis strain S1 was found to be at temperature 40 °C, pH 7, acetaminophen at concentration of 300 (mg/L) and agitation speed 165 rpm. The GC–MS and FTIR was used for identification of metabolites produced during acetaminophen degradation and the partial metabolic pathway for degradation of acetaminophen was also proposed .

Degradation of acetaminophen in photo-enzyme coupling system with natural organic matters from different sources

Acetaminophen (AAP) is one of the most commonly prescribed over-the-counter drugs with wide distribution in surface water, which has attracted great attention around the world. Photodegradation and enzymatic transformation are important processes for the removal of AAP in water. The influence of natural organic matter (NOM) from different sources on the transformation of AAP by horseradish peroxidase (HRP) in sunlit water was systematically studied. NOM can effectively promote the combined degradation rate of AAP in photo-enzyme coupling system (PECS), and the promotion extents of different NOMs were dependent on their aromaticity and average molecular weights. NOM with low aromaticity and low average molecular weight is more effective. In order to disclose the underlying effects of NOM clearly, the reaction mechanism was clarified through the determination of the photodegradation constant and enzymatic reaction constant. The effect of NOM structure on the photo-enzymatic transformation of AAP was quantified, which showed significant positive correlation with the SUVA₂₅₄ and E₂/E₃ of NOM. Further investigation revealed that the amount of H₂O₂ generated by NOM from different sources was also closely related to SUVA₂₅₄ and E₂/E₃ of NOM. The findings will facilitate understanding the environmental fate of AAP and other pharmaceutical products in natural water.

Biotransformation of Acetaminophen by intact cells and crude enzymes of bacteria: A comparative study and modelling

Acetaminophen (APAP), which is an active ingredient of many analgesic drugs, is one of the contaminants of emerging concern in the environment. Although APAP is biodegradable, it is frequently detected in treatment plant effluents, surface water and soil suggesting that there are factors affecting the fate of APAP in the environment. In this study, four strains of bacteria that can degrade APAP were isolated from soil. Those strains belonged to Rhodococcus, Pseudomonas, Flavobacterium, and Sphingobium genera of Bacteria. A series of kinetic experiments were performed on the isolates in shake-flasks to determine biodegradation rate constant as well as the effect of temperature, APAP concentration and cell density on the biodegradation rates. APAP biodegradation follows the first order reaction kinetics which is coupled with cell growth. The specific APAP biodegradation rate constant (k) for all strains was similar and equal to 0.19 ± 0.01 h^-1. The temperature, at which APAP biodegradation rate was maximum, was 35 °C. APAP biodegradation rate was linearly correlated with both the initial APAP concentration and the cell density. Initial step of the APAP biodegradation was hydrolysis of the amide bond which resulted in formation and accumulation of p-aminophenol suggesting that aryl acylamidase enzyme is responsible for the biotransformation. In addition, free and immobilized crude enzymes of the isolates transformed APAP at similar rates, comparable to the intact cells. This study showed that APAP biodegradation is achieved by a diverse group of bacteria having a similar enzyme operating at a constant kinetics which is very slow at environmentally relevant APAP concentrations. Natural removal of APAP in the environment is limited by kinetics, therefore APAP-bearing waste streams should be treated in adsorption enhanced biological systems before discharged into the environment.

Photocatalytic degradation of paracetamol on Pd-BiVO4 under visible light irradiation

In this study, Pd-BiVO₄ bearing highly dispersed Pd nanoparticles was prepared from pure BiVO₄ using an impregnation method. The pure BiVO₄ and Pd-BiVO₄ catalysts were characterized by X-ray diffraction, scanning electron microscopy, UV-visible diffuse reflection, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results showed that the prepared catalysts had a monoclinic scheelite structure and exhibited a flake-like morphology. Pd-BiVO₄ showed a distinct response in the visible light region, with an extended absorption edge at 550 nm. According to the Scherrer formula, the nanocrystal particle sizes of the BiVO₄ and Pd-BiVO₄ catalysts were 35 and 28 nm, respectively. Highly dispersed Pd nanoparticles with sizes of 2.5 ± 0.5 nm were observed on the BiVO₄ surface. Two Pd valence states, Pd(II) and Pd(0), were identified in a 2:1 ratio. Pd-BiVO₄ exhibited excellent activity for paracetamol (PCT) degradation, with 100% removal achieved in 1 h under visible light irradiation. During degradation, the mineralization ratio reached up to 40% total organic carbon removal. Two highly active species, namely, hydroxyl and superoxide radicals, were determined by electron spin resonance (ESR). Furthermore, the potential degradation of PCT in this system was proposed based on intermediate information obtained using HPLC-MS and Gauss analysis. The high dispersion and small size of Pd nanoparticles might favor the removal of emerging contaminants using the Pd-BiVO₄ photocatalytic system.

Insight into the nitrification kinetics and microbial response of an enriched nitrifying sludge in the biodegradation of sulfadiazine

The intensive use of antibiotics results in the continuous release of antibiotics into wastewater treatment systems, leading to the spread of antibiotic resistance. Nitrifying system is reported to be capable of degrading antibiotics, yet few studies have systematically investigated the inherent correlation among ammonium oxidation rate, antibiotic degradation and genetic expression of nitrifying bacteria along the process. This study selected a widely used sulfonamide antibiotic, sulfadiazine (SDZ), to investigate its biodegradation potential by an enriched nitrifying culture and the response of nitrifying bacteria against antibiotic exposure. Our results demonstrated that SDZ degradation was mainly contributed by cometabolism of ammonia-oxidizing bacteria (AOB), rather than biomass adsorption. The quantitative reverse transcription PCR (RT-qPCR) analysis revealed that the expression level of amoA gene was down-regulated due to the SDZ exposure. In addition, the degradation products of SDZ did not exhibit inhibitory effect on Escherichia coli K12, indicating the biotoxicity of SDZ could be mitigated after biodegradation. The findings offer insights regarding the biodegradation process of sulfonamide antibiotics via cometabolism by AOB.

Acetaminophen micropollutant: Historical and current occurrences, toxicity, removal strategies and transformation pathways in different environments

Acetaminophen (ACT) is commonly used as a counter painkiller and nowadays, it is increasingly present in the natural water environment. Although its concentrations are usually at the ppt to ppm levels, ACT can transform into various intermediates depending on the environmental conditions. Due to the complexity of the ACT degradation products and the intermediates, it poses a major challenge for monitoring, detection and to propose adequate treatment technologies. The main objectives of this review study were to assess (i) the occurrences and toxicities, (2) the removal technologies and (3) the transformation pathways and intermediates of ACT in four environmental compartments namely wastewater, surface water, ground water, and soil/sediments. Based on the review, it was observed that the ACT concentrations in wastewater can reach up to several hundreds of ppb. Amongst the different countries, China and the USA showed the highest ACT concentration in wastewater (≤300 μg/L), with a very high detection frequency (81-100%). Concerning surface water, the ACT concentrations were found to be at the ppt level. Some regions in France, Spain, Germany, Korea, USA, and UK comply with the recommended ACT concentration for drinking water (71 ng/L). Notably, ACT can transform and degrade into various metabolites such as aromatic derivatives or organic acids. Some of them (e.g., hydroquinone and benzoquinone) are toxic to human and other life forms. Thus, in water and wastewater treatment plants, tertiary treatment systems such as advanced oxidation, membrane separation, and hybrid processes should be used to remove the toxic metabolites of ACT.

Influences of nitrite on paracetamol degradation in dielectric barrier discharge reactor

The frequent detection of paracetamol in natural water increased environmental concerns. The dielectric barrier discharge (DBD) technology is an effective paracetamol removing method, however, this research showed that the removal of paracetamol using DBD technology at 30 min dropped from 100% to 53.3% as the initial paracetamol concentration increased from 10 mg/L to 100 mg/L, due to the formation of more competitive intermediate products at higher paracetamol concentration. The removal of TOC was found to be much slower than that of paracetamol, as paracetamol was removed completely after 5 min treatment, the removal rate of TOC was 46.3% after 20 min treatment under 500 W discharge power and 50 mL/min air flow rate. The orthogonal experiment showed that the removal of TOC was significantly influenced by the treatment time, discharge power and recirculating flow rate, while less influenced by the discharge frequency. In the removal process of paracetamol, nitrite ion that generated during DBD treatment reacted with paracetamol to form an intermediate product of 3-nitro-4-acetamidophenol. The presence of nitrite ion retarded the removal of 3-nitro-4-acetamidophenol and thus the TOC, however, the nitrate ion did not. The degradation of paracetamol followed a sequence of 3-nitro-4-acetamidophenol, nitrosophenol/acetamide, N-methylacetamide, acetamide and small molecule organic acids in the DBD reactor, and these intermediates were finally oxidized to CO₂, H₂O and NO₃^-.

A Review on Biological Processes for Pharmaceuticals Wastes Abatement-A Growing Threat to Modern Society

Over the last decades, the production and consumption of pharmaceuticals and health care products grew manifold, allowing an increase in life expectancy and a better life quality for humans and animals, in general. However, the growth in pharmaceuticals production and consumption comes with an increase in waste production, which creates a number of challenges as well as opportunities for the waste management industries. The conventional current technologies used to treat effluents have shown to be inefficient to remove or just to reduce the concentrations of these types of pollutants to the legal limits. The present review provides a thorough state-of-the-art overview on the use of biological processes in the rehabilitation of ecosystems contaminated with the pharmaceutical compounds most commonly detected in the environment and eventually more studied by the scientific community. Among the different biological processes, special attention is given to biosorption and biodegradation.

Cometabolic biodegradation of cephalexin by enriched nitrifying sludge: Process characteristics, gene expression and product biotoxicity

The nitrifying systems have been reported to be able to biodegrade micropollutants, yet it is still unclear about the cometabolism of ammonia-oxidizing bacteria (AOB) towards micropollutants, in particular their enzyme and transcriptional responses under exposure of micropollutants. This study investigated cometabolic biodegradation of a selected antibiotic, cephalexin (CFX), by an enriched nitrifying culture through a series of batch experiments, together with the assessments of enzymatic activity, key gene expression, and biotoxicity of the degradation products. More than 99% CFX with an initial concentration of 50 μg/L could be removed with the presence of ammonium, while <44% of CFX removal was observed in the absence of ammonium, suggesting the cometabolic degradation of CFX by ammonia-oxidizing bacteria (AOB). After the addition of 50 μg/L CFX, the ammonia oxidizing rate (AOR) decreased from 36.6 to 11.0 mg N/(L·h·g VSS), followed by a slight recovery when CFX concentration decreased to below 8 μg/L. Ammonia monooxygenase (AMO) activity showed a similar trend with that of AOR. The quantitative reverse transcription PCR assay indicated that the expression level of amoA gene was significantly upregulated (up to 3-fold, p < 0.05) due to the addition of CFX, while decreased to the normal level once CFX was degraded, suggesting a mechanism of AOB to neutralize the toxicity of CFX by metabolizing ammonia more effectively. Meanwhile, the biotoxicity test showed the degradation products of CFX did not exhibit any antibacterial impacts in terms of cell viability, compared to the parent compounds. Our finding shed a light on AMO-mediated cometabolic biodegradation of antibiotics in nitrifying cultures.

KOH-super activated carbon from biomass waste: Insights into the paracetamol adsorption mechanism and thermal regeneration cycles

A super activated carbon (SAC) was produced by KOH-activation of a biomass waste for paracetamol (PCT) adsorption from aqueous solution and for adsorption-thermal regeneration cycles. The SAC and the regenerated SAC after five adsorption-regeneration cycles (RSAC-5th) were fully characterized by several techniques. The N₂ physisorption showed that the S_BET values of the SAC and RSAC-5th are remarkably different, being 2794 m² g^-1 and 889 m² g^-1, respectively. The XPS analysis demonstrated that the SAC surface is composed by oxygen containing-groups, whilst the RSAC-5th also presents nitrogen ones, provenient from the PCT molecules. The adsorption studies revealed that the maximum adsorption capacity (Q_m) for the SAC (356.22 mg g^-1) is higher than that for RSAC-5th (113.69 mg g^-1). Also, the results demonstrated that the PCT adsorption is governed by both physisorption and chemisorption and the ab initio calculations showed the chemisorption mainly occurs in carboxylic groups.

Roles of ammonia-oxidizing bacteria in improving metabolism and cometabolism of trace organic chemicals in biological wastewater treatment processes: A review

While there has been a significant recent improvement in the removal of pollutants in natural and engineered systems, trace organic chemicals (TrOCs) are posing a major threat to aquatic environments and human health. There is a critical need for developing potential strategies that aim at enhancing metabolism and/or cometabolism of these compounds. Recently, knowledge regarding biodegradation of TrOCs by ammonia-oxidizing bacteria (AOB) has been widely developed. This review aims to delineate an up-to-date version of the ecophysiology of AOB and outline current knowledge related to biodegradation efficiencies of the frequently reported TrOCs by AOB. The paper also provides an insight into biodegradation pathways by AOB and transformation products of these compounds and makes recommendations for future research of AOB. In brief, nitrifying WWTFs (wastewater treatment facilities) were superior in degrading most TrOCs than non-nitrifying WWTFs due to cometabolic biodegradation by the AOB. To fully understand and/or enhance the cometabolic biodegradation of TrOCs by AOB, recent molecular research has focused on numerous crucial factors including availability of the compounds to AOB, presence of growth substrate (NH₄-N), redox potentials, microorganism diversity (AOB and heterotrophs), physicochemical properties and operational parameters of the WWTFs, molecular structure of target TrOCs and membrane-based technologies, may all significantly impact the cometabolic biodegradation of TrOCs. Still, further exploration is required to elucidate the mechanisms involved in biodegradation of TrOCs by AOB and the toxicity levels of formed products.

Removal of Paracetamol Using Effective Advanced Oxidation Processes

Fenton, photo-Fenton, and photo-induced oxidation, were investigated and compared for the treatment of 0.26 mmol L^-1 of paracetamol (PCT) in a deionised water matrix, during a reaction span of 120.0 min. Low and high Fenton reagent loads were studied. Particularly, the initial concentration of Fe²⁺ was varied between 0.09 and 0.18 mmol L^-1 while the initial concentration of H₂O₂ was varied between 2.78 and 11.12 mmol L^-1. The quantitative performance of these treatments was evaluated by: (i) measuring PCT concentration; (ii) measuring and modelling TOC conversion, as a means characterizing sample mineralization; and (iii) measuring cytotoxicity to assess the safe application of each treatment. In all cases, organic matter mineralization was always partial, but PCT concentration fell below the detection limit within 2.5 and 20.0 min. The adopted semi-empirical model revealed that photo induced oxidation is the only treatment attaining total organic matter mineralization ( ξ MAX = 100% in 200.0 min) at the expense of the lowest kinetic constant (k = 0.007 min^-1). Conversely, photo-Fenton treatment using high Fenton reagent loads gave a compromise solution ( ξ MAX = 73% and k = 0.032 min^-1). Finally, cytotoxicity assays proved the safe application of photo-induced oxidation and of photo-Fenton treatments using high concentrations of Fenton reagents.

A kinetic study for the Fenton and photo-Fenton paracetamol degradation in an annular photoreactor

A kinetic model describing Fenton and photo-Fenton degradation of paracetamol (PCT) and consumption of hydrogen peroxide (H₂O₂) was proposed. A set of Fenton and photo-Fenton experiments (18 runs in total) was performed by fixing the initial concentration of PCT to 40 mg L^-1 and varying the initial concentrations of H₂O₂ and ferrous ion, Fe²⁺. The experimental set-up was a well-stirred annular photoreactor equipped with an actinic BL TL-DK 36 W/10 1SL lamp. Experimental results highlighted that PCT is no more detected by HPLC analysis within a minimum reaction time of 2.5 and a maximum reaction time of 15.0 min. Besides, a maximum conversion of total organic carbon (TOC) of 68.5% was observed after 75 min of reaction in case of using UV radiation and the highest concentrations of the Fenton reagents. The experimental data were used to fit the kinetic model. The radiation field inside the reactor was taken into account through the local volumetric rate of photon absorption, evaluated by assuming a line source model with spherical and isotropic emission. The kinetic parameters were estimated by using a non-linear least-squares regression procedure and root mean square errors (RMSE) were calculated in order to validate the feasibility of the proposed model. A good agreement between experimental and predicted data was observed and the lowest values of RMSE resulted in 5.84 and 9.59% for PCT and H₂O₂ normalized concentrations, respectively.