Paracetamol degradation pathways in soil after biochar addition

Construction of biocatalysts based on P450BM3 for the degradation of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are widespread pollutants in aquatic environments, posing significant risks to both ecosystems and human health due to their persistence and bioaccumulation. Effective and sustainable degradation methods are urgently required to address this environmental challenge. This study aims to design and optimize a cytochrome P450BM3-based biocatalyst for the rapid and efficient degradation of NSAIDs by direct chemical intervention and protein engineering. The novel biocatalyst achieved efficient biodegradation of four common NSAIDs. Notably, the F87I/T268D mutant achieved 99.22 % degradation of diclofenac (DCF) within 10 min, and degraded meloxicam (MEL) and phenylbutazone (PBZ) at rates of 98.86 % and 90.51 % within 5 min, respectively. Furthermore, the F87G mutant accomplished 99.08 % degradation of acetaminophen (APAP) within just 2 min. The catalytic properties of P450BM3 and its mutants were evaluated through kinetic studies, and potential degradation pathways of the four NSAIDs were proposed in conjunction with UPLC-MS. This study provides a novel biocatalytic approach for the rapid degradation of NSAIDs in aquatic systems, offering considerable environmental benefits for pollution mitigation.

Biotransformation pathways of pharmaceuticals and personal care products (PPCPs) during acidogenesis and methanogenesis of anaerobic digestion

Pharmaceuticals and personal care products (PPCPs) exhibit varying biodegradability during the acidogenic and methanogenic phases of anaerobic digestion. However, there is limited information regarding the end products generated during these processes. This work investigates the biotransformation products (BTPs) generated in a two-phase (TP) acidogenic-methanogenic (Ac-Mt) bioreactor using advanced suspect and nontarget strategies. Fourteen BTPs were confidently identified from ten parent PPCPs including carbamazepine (CBZ), naproxen (NPX), diclofenac (DCF), ibuprofen (IBU), acetaminophen (ACT), metoprolol (MTP), sulfamethoxazole (SMX), ciprofloxacin (CIP), methylparaben (MPB) and propylparaben (PPB). These BTPs were linked with oxidation reactions such as hydroxylation, demethylation and epoxidation. Their generation was related to organic acid production, since all metabolites were detected during acidogenesis, with some being subsequently consumed during methanogenesis, e.g., aminothiophenol and kynurenic acid. Another group of BTPs showed increased concentrations under methanogenic conditions, e.g., hydroxy-diclofenac and epoxy-carbamazepine. The most PPCPs showed high removal efficiencies (> 90 %) - SMX, CIP, NPX, MTP, ACT, MPB, PPB, while DCF, CBZ and IBU demonstrated higher persistence - DCF (42 %); CBZ (40 %), IBU (47 %). The phase separation of anaerobic digestion provided a deeper understanding of the biotransformation pathways of PPCPs, in addition to enhancing the biodegradability of the most persistent compounds, i.e., DCF, CBZ and IBU.

The Influence of Activated Sludge Augmentation on Its Ability to Degrade Paracetamol

Paracetamol is one of the most commonly used painkillers. Its significant production and consumption result in its presence in the environment. For that reason, paracetamol has a negative impact on the organisms living in ecosystems. Therefore, it is necessary to develop effective methods to remove paracetamol from sewage. One of the methods is the bioaugmentation of activated sludge with organisms with increased degradation potential in relation to paracetamol. This study determined the effectiveness of paracetamol degradation by activated sludge augmented with a free or immobilised Pseudomonas moorei KB4. To immobilise the strain, innovative capsules made of cellulose acetate were used, the structure of which provides an optimal environment for the development of bacteria. Augmentation with both a free and immobilised strain significantly improves the efficiency of paracetamol biodegradation by activated sludge. Over a period of 30 days, examined systems allowed ten doses of paracetamol decomposition, while the unaugmented system degraded only four. At the same time, using the immobilised strain does not significantly affect the functioning of the activated sludge, which was reflected in the stability of processes such as nitrification. Due to the high stability of the preparation, it can become a valuable tool in wastewater treatment processes.

Influence of entropy on catalytic performance of high-entropy oxides (NiMgZnCuCoOx) in peroxymonosulfate-mediated acetaminophen degradation

Developing a high-performance activator is crucial for the practical application of peroxymonosulfate-based advanced oxidation processes (PMS-AOPs). High-entropy oxides (HEOs) have attracted increasing attention due to their stable crystal structure, flexible composition and unique functionality. However, research into the mechanisms by which HEOs function as PMS activators for degrading organic pollutants remains insufficient, and the relationship between entropy and the catalytic performance of HEOs has yet to be clarified. In this study, we synthesized NiMgZnCuCoOx with different levels of entropy as PMS activators for acetaminophen (APAP) degradation, and observed a significant effect for entropy on the catalytic performance. Sulfate radicals (SO4•‒) were identified as the primary reactive oxygen species (ROS), while hydroxyl radicals (•OH) and singlet oxygen (1O2) act as secondary ROS during APAP degradation. Both the Co2+ contents and the oxygen vacancy concentration in NiMgZnCuCoOx are found to increase with the entropy. An increase in the Co2+ sites leads to more activation sites for PMS activation, while excessive oxygen vacancies consume PMS, producing weak oxidation species, and affect the electron-donating ability of Co2+. Consequently, the NiMgZnCuCoOx with middle level of entropy exhibits the optimal performance with APAP degradation rate and mineralization rate reaching 100% and 74.22%, respectively. Furthermore, the degradation intermediates and their toxicities were assessed through liquid chromatography-mass spectrometry and quantitative structure-activity relationship analysis. This work is expected to provide critical insight into the impact of the HEOs entropy on the PMS activation and guide the rational design of highly efficient peroxymonosulfate activators for environmental applications.

Prenatal acetaminophen exposure and the developing ovary: Time, dose, and course consequences for fetal mice

Acetaminophen is an emerging endocrine disrupting chemical and has been detected in various natural matrices. Numerous studies have documented developmental toxicity associated with prenatal acetaminophen exposure (PAcE). In this study, we established a PAcE Kunming mouse model at different time (middle pregnancy and third trimester), doses (low, middle, high) and courses (single or multi-) to systematically investigate their effects on fetal ovarian development. The findings indicated PAcE affected ovarian development, reduced fetal ovarian oocyte number and inhibited cell proliferation. A reduction in mRNA expression was observed for genes associated with oocyte markers (NOBOX and Figlα), follicular development markers (BMP15 and GDF9), and pre-granulosa cell steroid synthase (SF1 and StAR). Notably, exposure in middle pregnancy, high dose, multi-course resulted in the most pronounced inhibition of oocyte development; exposure in third trimester, high dose and multi-course led to the most pronounced inhibition of follicular development; and in third trimester, low dose and single course, the inhibition of pre-granulosa cell function was most pronounced. Mechanistic investigations revealed that PAcE had the most pronounced suppression of the ovarian Notch signaling pathway. Overall, PAcE caused fetal ovarian multicellular toxicity and inhibited follicular development with time, dose and course differences.

Biodegradation of acetaminophen: Microcosm centric genomic-proteomic-metabolomics evidences

Acetaminophen (APAP) is a frequently used, over-the-counter analgesic and antipyretic medication. Considering increase in global consumption, its ubiquity in environment with potential toxic impacts has become a cause of great concern. Hence, bioremediation of this emerging contaminant is of paramount significance. The present study incorporates a microcosm centric omics approach to gain in-depth insights into APAP degradation by Paracoccus sp. APAP_BH8. It can metabolize APAP (300 mg kg-1) within 16 days in soil microcosms. Genome analysis revealed potential genes capable of mediating degradation includes M20 aminoacylase family protein, guanidine deaminase, 4-hydroxybenzoate 3-monooxygenase, and 4-hydroxyphenylpyruvate dioxygenase. Whole proteome analysis showed differential expression of enzymes and bioinformatics provided evidence for stable binding of intermediates at the active site of considered enzymes. Metabolites identified were 4-aminophenol, hydroquinone, and 3-hydroxy-cis, cis-muconate. Therefore, Paracoccus sp. APAP_BH8 with versatile enzymatic and genetic attributes can be a promising candidate for formulating improved in situ APAP bioremediation strategies.

Integrating bioavailability measurements in persistence testing of partially biodegradable organic chemicals in soil

Overestimation of risk is one of the main problems in environmental risk assessments if only total concentration of organic pollutants is considered. In this study, we integrated bioavailability measurements into persistence testing of pollutants in soil to show that it is the key to have a more realistic environmental risk assessment (ERA). To this integration, two standardized methods were used: OECD 307, as persistence test, and ISO 16751: 2020, to bioavailability measurements based on 20 h extractions with a strong adsorbent (Tenax), using pyrene and carbamazepine as model test substances. Because the ISO method was initially designed for nonpolar compounds with log Kow > 3, a slight adaptation was necessary for carbamazepine (log Kow = 2.7), assuming this also as an extension of the applicability domain of the method. During the biodegradation of these compounds, the mineralization extents did not exceed 4 %, giving rise to transformation products. Therefore, the bioavailability measurements covered both the parent compound and the metabolites produced. In the case of pyrene, the partial transformation carried out by a specialized microbial inoculum accounted for, respectively, 32 % or 40 % of the initial concentration (4 mg kg-1) in unamended or compost-amended soil. Only 1 % was present as hydrophilic transformation products that were not trapped by Tenax, but partitioned into the water. The nonbioavailable residue increased in both soils after biodegradation. The distribution of chemicals in the different phases of the system was the key to assess more realistically the shifts in bioavailability during persistence testing. The same procedure was carried out for carbamazepine where an additional desorption study showed a slower desorption rate of the parent compound after incubation. In this case, 25 % of transformation products was mobilized to the aqueous phase. Our results show that bioavailability measurements provide valuable information when integrated in persistence testing, therefore contributing to realism in prospective ERA scenarios.

Applications, impacts, and management of biochar persistent free radicals: A review

Biochar is a promising environmental contaminant remediation agent because of its adsorptive and catalytic properties. However, the environmental effects of persistent free radicals (PFRs) produced by biomass pyrolysis (biochar production) are still poorly understood, though they have received increasing research attention in recent years. Although PFRs both directly and indirectly mediate biochar's removal of environmental pollutants, they also have the potential to cause ecological damage. In order to support and sustain biochar applications, effective strategies are needed to control the negative effects of biochar PFRs. Yet, there has been no systematic evaluation of the environmental behavior, risks, or management techniques of biochar PFRs. Thus, this review: 1) outlines the formation mechanisms and types of biochar PFRs, 2) evaluates their environmental applications and potential risks, 3) summarizes their environmental migration and transformation, and 4) explores effective management strategies for biochar PFRs during both production and application phases. Finally, future research directions are recommended.

Olive mill wastewater from a liquid biological waste to a carbon/oxocalcium composite for selective and efficient removal of methylene blue and paracetamol from aqueous solution

In this study, a Carbon/Oxocalcium was prepared from olive mill wastewater and successfully applied to the removal of paracetamol and methylene blue (MB) from an aqueous medium. The optimized composite (0.3 % CaO) is rich in anionic sites, porous and has a specific surface area of about 1383 m².g^-1. Adsorption tests showed significant adsorption capacities up to 1141 mg.g^-1. The adsorption of MB and paracetamol is well described by the Redlich-Peterson and Dubinin-Radushkevich isotherm, respectively. Moreover, the adsorption kinetics fitted to pseudo-second order. The π -π interactions, hydrogen bonds and electrostatic interactions were responsible for the adsorption of paracetamol and MB substrates. This work develops by a single, easy and simple action a new effective and selective material for the removal of emerging pollutants, a new method for the development of more stable carbon composites and a cost-effective method for the valorization of olive mill wastewater.