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[This corrects the article DOI: 10.1371/journal.pone.0275484.].

Combining carboxylation reactions using carbon dioxide (CO[sub.2]) as a reactant with phenol results in creation of new C-C bonds, and represents one of the most promising routes in sustainable utilization of ubiquitous and readily available resources for production of highly valuable products. This study provides a detailed and well-structured investigation of the effect of various reaction conditions (reactant loading, reaction duration, temperature, CO[sub.2] pressure) on the carboxylation of phenol. Sodium phenoxide carboxylation showed well-resolved trends with variation of temperature and time, and resulted in production of salicylic acid (SA) in the range of 11.4 to 47.8%, 4-hydoxybenzoic acid (4HBA) in the range of 2.0 to 8.2%, while the dicarboxylated 4-hydroxyisophthalic acid (4HiPh) was only detected in trace amounts. The effect of the variation of reactant content was shown to be significantly influenced by the reactor size, solid/vessel and gas/solid contact area, as well as the efficiency of the stirring. CO[sub.2] pressure was shown to be a crucial element, where reactions carried out below 2 MPa CO[sub.2] did not show any activity. While investigating the reaction mechanism, it was shown that the salt analogues of potential products could be acidified in situ by the moisture present, and immediately degraded back to phenol, thus lowering yields of potentially obtained products. The experimental results were successfully used to compose a kinetic model, which very well describes the experimentally obtained results. As such, this study provides a valuable dataset for valorization of lignocellulosic aromatic compounds as well as highly abundant and environmentally detrimental carbon dioxide into industrially valuable mono- and dicarboxylic acids.

[This corrects the article DOI: 10.1371/journal.pgen.1008873.].

A novel ternary heterojunction material In.sub.2O.sub.3/In.sub.2S.sub.3/ZnIn.sub.2S.sub.4 was synthesized, and a photoelectrochemical sensor was fabricated for the non-invasive test of dopamine (DA) in sweat. In.sub.2O.sub.3 multihollow microtubules were synthesized and then In.sub.2S.sub.3 was formed on their surface to construct a type-I heterojunction between In.sub.2S.sub.3 and In.sub.2O.sub.3. ZnIn.sub.2S.sub.4 was further introduced to form a Z-scheme heterojunction between In.sub.2S.sub.3/ZnIn.sub.2S.sub.4. Under photoexcitation, the photogenerated holes of In.sub.2O.sub.3 transferred to the valence band of In.sub.2S.sub.3, superimposed with the holes produced by In.sub.2S.sub.3, leads to a significantly higher photocatalytic oxidation capacity of In.sub.2O.sub.3/In.sub.2S.sub.3/ZnIn.sub.2S.sub.4 ternary composites than that of In.sub.2O.sub.3/In.sub.2S.sub.3. The Z-scheme heterojunction accelerates the transfer of photogenerated electrons accumulated on the type-I heterojunction. In the presence of DA, it is rapidly oxidized into polydopamine (PDA) by In.sub.2O.sub.3/In.sub.2S.sub.3, and the benzoquinone groups of PDA compete for the photogenerated electrons to reduce the current in the external circuit, whereby DA determination is achieved. Owing to the combination of type-I and Z-scheme heterojunction, the sensor showed extremely high sensitivity, with a detection limit of 3.94 x 10.sup.-12 mol/L. It is one of the most sensitive methods for DA detection reported and has been applied to the determination of DA in human sweat. Graphical

MoS[sub.2]/TiO[sub.2]-based nanostructures have attracted extensive attention due to their high performance in many fields, including photocatalysis. In this contribution, MoS[sub.2] nanostructures were prepared via an in situ bottom-up approach at the surface of shape-controlled TiO[sub.2] nanoparticles (TiO[sub.2] nanosheets and bipyramids). Furthermore, a multi-technique approach by combining electron microscopy and spectroscopic methods was employed. More in detail, the morphology/structure and vibrational/optical properties of MoS[sub.2] slabs on TiO[sub.2] anatase bipyramidal nanoparticles, mainly exposing 101 facets, and on TiO[sub.2] anatase nanosheets exposing both 001 and 101 facets, still covered by MoS[sub.2], were compared. It was shown that unlike other widely used methods, the bottom-up approach enabled the atomic-level growth of well-defined MoS[sub.2] slabs on TiO[sub.2] nanostructures, thus aiming to achieve the most effective chemical interactions. In this regard, two kinds of synergistic heterojunctions, namely, crystal face heterojunctions between anatase TiO[sub.2] coexposed 101 and 001 facets and semiconductor heterojunctions between MoS[sub.2] and anatase TiO[sub.2] nanostructures, were considered to play a role in enhancing the photocatalytic activity, together with a proper ratio of (101), (001) coexposed surfaces.

The beneficial health effects of cranberries have been attributed to their (poly)phenol content. Recent studies have investigated the absorption, metabolism and excretion of cranberry (poly)phenols; however, little is known about whether they follow a dose response in vivo at different levels of intake. An acute double-blind randomized controlled trial in 10 healthy men with cranberry juices containing 409, 787, 1238, 1534 and 1910 mg total (poly)phenols was performed. Blood and urine were analyzed by UPLC-Q-TOF-MS. Sixty metabolites were identified in plasma and urine including cinnamic acids, dihydrocinnamic, flavonols, benzoic acids, phenylacetic acids, benzaldehydes, valerolactones, hippuric acids, catechols, and pyrogallols. Total plasma, but not excreted urinary (poly)phenol metabolites, exhibited a linear dose response (r2 = 0.74, p < 0.05), driven by caffeic acid 4-O-ß-d-glucuronide, quercetin-3-O-ß-d-glucuronide, ferulic acid 4-O-ß-d-glucuronide, 2,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, ferulic acid, caffeic acid 3-O-ß-d-glucuronide, sinapic acid, ferulic acid 4-O-sulfate, 3-hydroxybenzoic acid, syringic acid, vanillic acid-4-O-sulfate, (4R)-5-(3′-hydroxyphenyl)-γ-valerolactone-4′-O-sulfate, 4-methylgallic acid-3-O-sulfate, and isoferulic acid 3-O-sulfate (all r2 ≥ 0.89, p < 0.05). Inter-individual variability of the plasma metabolite concentration was broad and dependent on the metabolite. Herein, we show that specific plasma (poly)phenol metabolites are linearly related to the amount of (poly)phenols consumed in cranberry juice. The large inter-individual variation in metabolite profile may be due to variations in the gut microbiome.

Clinacanthus nutans (Sabah snake grass) is widely recognized for its pharmacological properties, particularly its high phenolic content and antioxidant activity. However, the optimization of its ultrasonic-assisted extraction (UAE) remains underexplored. This study aims to enhance the extraction efficiency of phenolic compounds from Clinacanthus nutans leaves using ionic liquid (IL) binary solvents, with optimization based on Peleg's model and Response Surface Methodology (RSM). Peleg's model was used to determine the optimal extraction time, while RSM with a Central Composite Rotatable Design (CCRD) was applied to evaluate the effects of ultrasonic frequency (40-60 kHz) and the ratio of ILs to water (2:8, 5:5 and 8:2) on total phenolic content (TPC), DPPH radical scavenging activity, and Ferric Reducing Antioxidant Power (FRAP). The experimental results were statistically analyzed using ANOVA, model fitting, and desirability functions. Peleg's model indicated that the predicted maximum total phenolic content (TPC) of 42.556 ± 0.0003 mg GAE/g was achieved at an ultrasonic frequency of 50 kHz within 3 hours, making this duration as the predictive model benchmark for further optimization. The optimal extraction conditions were identified as an ultrasonic frequency of 60 kHz and an IL-to-water ratio of 2:8, yielding a maximum TPC of 0.01 ± 7.97 x 10.sup.-5 mg GAE/g, DPPH antioxidant activity of 95.08 ± 0.57%, and FRAP antioxidant capacity of 6.31 ± 0.10 mg AEAC/g. Peleg's model inadequately predicted the best exhaustive extraction time prior to RSM leading to a low TPC value throughout the optimization process while maintaining high in antioxidant efficacy. However, the use of IL binary solvents significantly enhanced the release of phenolic compounds compared to conventional solvents, demonstrating their potential as a green extraction alternative. This study highlights the effectiveness of ultrasonic-assisted extraction combined with IL binary solvents for maximizing the recovery of bioactive compounds from Clinacanthus nutans leaves. The optimized extraction method can be beneficial for pharmaceutical, nutraceutical, and functional food industries. Future research should focus on identifying specific phenolic compounds using High-Performance Liquid Chromatography (HPLC), combined kinetic and diffusion equilibrium model and further refining process optimization parameters (e.g., longer concoction duration) to enhance yield efficiency.

Anaerobic biodegradation of toxic compounds found in industrial wastewater is an attractive solution allowing the recovery of energy and resources but it is still challenging due to the low kinetics making the anaerobic process not competitive against the aerobic one. In this review, we summarise the present state of knowledge on the anaerobic biodegradation process for phenol, a typical target compound employed in toxicity studies on industrial wastewater treatment. The objective of this article is to provide an overview on the microbiological and technological aspects of anaerobic phenol degradation and on the research needs to fill the gaps still hindering the diffusion of the anaerobic process. The first part is focused on the microbiology and extensively presents and characterises phenol-degrading bacteria and biodegradation pathways. In the second part, dedicated to process feasibility, anaerobic and aerobic biodegradation kinetics are analysed and compared, and strategies to enhance process performance, i.e. advanced technologies, bioaugmentation, and biostimulation, are critically analysed and discussed. The final section provides a summary of the research needs. Literature data analysis shows the feasibility of anaerobic phenol biodegradation at laboratory and pilot scale, but there is still a consistent gap between achieved aerobic and anaerobic performance. This is why current research demand is mainly related to the development and optimisation of powerful technologies and effective operation strategies able to enhance the competitiveness of the anaerobic process. Research efforts are strongly justified because the anaerobic process is a step forward to a more sustainable approach in wastewater treatment.Key points• Review of phenol-degraders bacteria and biodegradation pathways.• Anaerobic phenol biodegradation kinetics for metabolic and co-metabolic processes.• Microbial and technological strategies to enhance process performance.

To identify intestinal bacteria that produce phenols (phenol and p-cresol), we screened 153 strains within 152 species in 44 genera by culture-based assay using broth media supplemented with 200 µM each of tyrosine and its predicted microbial metabolic intermediates (4-hydroxyphenylpyruvate, DL-4-hydroxyphenyllactate, 3-(p-hydroxyphenyl)propionate, 4-hydroxyphenylacetate and 4-hydroxybenzoate). Phenol-producing activity was found in 36 strains and p-cresol-producing activity in 55 strains. Fourteen strains had both types of activity. Phylogenetic analysis based on the 16S rRNA gene sequences of strains that produced 100 µM or more of phenols revealed that 16 phenol producers belonged to the Coriobacteriaceae, Enterobacteriaceae, Fusobacteriaceae and Clostridium clusters I and XIVa; four p-cresol-producing bacteria belonged to the Coriobacteriaceae and Clostridium clusters XI and XIVa; and one strain producing both belonged to the Coriobacteriaceae. A genomic search for protein homologs of enzymes involved in the metabolism of tyrosine to phenols in 10 phenol producers and four p-cresol producers, the draft genomes of which were available in public databases, predicted that phenol producers harbored tyrosine phenol-lyase or hydroxyarylic acid decarboxylase, or both, and p-cresol producers harbored p-hydroxyphenylacetate decarboxylase or tyrosine lyase, or both. These results provide important information about the bacterial strains that contribute to production of phenols in the intestine.