Presence Of Catechol Research Articles

Preparation of surface molecular imprinting fluorescent sensor based on magnetic porous silica for sensitive and selective determination of catechol.

A magnetic fluorescent molecularly imprinted sensor was successfully prepared and implemented to determine catechol (CT). Fe3O4 nanoparticles were synthesized by the solvothermal technique and mesoporous Fe3O4@SiO2@mSiO2 imprinted carriers were prepared by coating nonporous and mesoporous SiO2 shells on the surface of the Fe3O4 subsequently. The magnetic surface molecularly imprinted fluorescent sensor was created after the magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane to introduce double bonds on thesurface of the carries and the polymerization was carried out in the presence of CT and fluorescent monomers. The magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane and double bonds were introduced on the surface of the carriers. After CT binding with the molecularly imprinted polymers (MIPs), the fluorescent intensity of the molecularly imprinted polymers (Ex = 400nm, Em = 523nm) increased significantly. The fluorescent intensity ratio (F/F0) of the sensor demonstrated a favorable linear correlation with the concentration of CT between 5 and 50μM with a detection limit of 0.025μM. Furthermore, the sensor was successfully applied to determine CT in actual samples with recoveries of 96.4-105% and relative standard deviations were lower than 3.5%. The results indicated that the research of our present work provided an efficient approach for swiftly and accurately determining organic pollutant in water.

Polyphenol‐Based Assembly Nanosystems as Multifunctional Biopharmaceutical Platform

Polyphenolic compounds are a diverse collection of secondary metabolites. They are present in nature and have potential therapeutic and medical value due to their anti‐inflammatory, antibacterial, and antitumor activities, as well as antioxidant capacity. Moreover, polyphenolic compounds can bind to biological macromolecules (e.g., peptides, proteins, nucleic acids, etc.) through various interactions, including hydrogen bonds, hydrophobic interactions, electrostatic interactions, π interactions, metal–ligand bonds, and covalent bonds, in the presence of catechol and gallol moieties. This endows polyphenols with strong adhesion and provides diverse approaches for designing and constructing biopharmaceutical platforms using multifunctional polyphenol components. Herein, a review of the synthesis and characteristics of polyphenol‐based bioactive assembly nanosystems by concentrating on the multi‐interactions between polyphenols and biomacromolecules is demonstrated. The polyphenol‐based bioactive assembly nanosystems exhibit remarkable versatility in a wide range of biological applications, including protein/antigen delivery, hemostasis, antimicrobial, gene therapy, and cell therapy. This may shed light on future developments in the field of bio‐based medicine.

Synthesis and Characterization of CuO@PANI composite: A new prospective material for electrochemical sensing

Herein, one-step oxidation-chemical polymerization in situ to prepare a composite of copper oxide nanoparticles doped with polyaniline(CuO@PANI) was investigated in order to check the electrochemical properties.The influence of the synthetic approach, the doping effectiveness of copper oxide nanoparticles, as well as the structure of the as-synthesized composite, were all studied. The synthesized compositewas characterized by field emission SEM and XFR. The results showed favorable interaction between PANI and CuO NPs. The electron microscopy analysis of the composite indicates that CuO is well dispersed and agglomerated in the PANI matrix as can be seen clearly in X-ray fluorescence analysis. Moreover, X-ray assessment indicated that the amount of CuO NPs strengthens the crystallinity of PANI. Moreover, to investigate the electrochemical performance of CuO@PANI, the composite was drop-casted on a glassy carbon electrode surface and its electrocatalytic activity was examined via a potentiostate in presence of catechol. As a result, the electrical conductivity of the synthesized hybrid was found to be drastically increased (around 60 %) as compared to that of pure PANI at room temperaturedue to the formation of conducting path between CuO and PANI surface. Hence, through this work we highly recommend to use this hybrid for future electrochemical sensing applications.

Electrochemical detection of bisphenol A in presence of catechol and hydroquinone at copper oxide modified carbon paste electrode

Utilizing co-precipitation method copper oxide (CuO) nanomaterials are prepared and analyzed using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Energy-dispersive X-ray Analysis (EDAX) technique. Copper oxide modified carbon paste electrode (CuOMCPE) were used as electrochemical sensor for the study of catechol, bisphenol A and hydroquinone using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The analyte species shows high reproducibility in voltammetric response because of his enhancement. The CuOMCPE exhibits the better electrocatalytic property for the oxidation of BPA, CC and HQ. Parameters like scan rate and concentration of Bisphenol A (BPA), catechol (CC) and hydroquinone (HQ) were studied by CuOMCPE. The effect of scan rate on CuOMCPE was studied individually for BPA, CC, and HQ and shows that the electrode process was adsorption-controlled. The modifier exhibits good limit of detection (LOD) and limit of quantification (LOQ) values are found at 2.48 μM and 8.26 μM for BPA, 3.22 μM and 10.73 μM for CC, 4.94 and 16.48 μM for HQ respectively. The CuOMCPE shows high stability and reproducibility compared to BCPE. DPV were studied using CuOMCPE gives three well defined peaks located at 0.4406(BPA), 0.1043 V (CC) and 0.0075 V (HQ) respectively. The simultaneous and interference study of analytes were studied using CuOMCPE. Hence, the modifier exhibits good selectivity and sensitivity for the study of BPA, HQ and CC.

A pilot study for enhanced transformation of a metabolite 3,5-dichloroaniline derived from dicarboximide fungicides through immobilized laccase mediator system.

This pilot investigation aimed to evaluate the removal efficiency and the underlying biocatalytic pathways of immobilized fungal laccase during the oxidative biotransformation of a non-phenolic metabolite, 3,5-dichloroaniline (3,5-DCA) derived from dicarboximide fungicides. The maximum loading of laccase on the microporous support surfaces could reach 36.4mg/g. The immobilized laccase on the microporous support surfaces exhibited excellent thermal stability, pH adaptability, storage stability, and reusability compared to free laccase. The ILMS assay indicated that the immobilized laccase efficiently removed studied 3,5-DCA (99-100%) in the aqueous medium, within 72h in the presence of catechol. In this study, we identified three coupling reaction products during the removal of 3,5-DCA through an ILMS assay. Based on the identified coupling reaction products, we proposed the reaction pathway for the biotransformation of 3,5-DCA by immobilized laccase, which was shown to be potentially useful in the sustainable environmental remediation of aniline metabolite (i.e., 3,5-DCA) derived from dicarboximide fungicides.

Unravelling the genetic and functional diversity of dominant bacterial communities involved in manure co-composting bioremediation of complex crude oil waste sludge

The present study aimed to characterize the bacterial community and functional diversity in co-composting microcosms of crude oil waste sludge amended with different animal manures, and to evaluate the scope for biostimulation based in situ bioremediation. Gas chromatography–mass spectrometry (GC–MS) analyses revealed enhanced attenuation (>90%) of the total polyaromatic hydrocarbons (PAHs); the manure amendments significantly enhancing (up to 30%) the degradation of high molecular weight (HMW) PAHs. Microbial community analysis showed the dominance (>99% of total sequences) of sequences affiliated to phyla Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. The core genera enriched were related to hydrocarbon metabolism (Pseudomonas, Delftia, Methylobacterium, Dietzia, Bacillus, Propionibacterium, Bradyrhizobium, Streptomyces, Achromobacter, Microbacterium and Sphingomonas). However, manure-treated samples exhibited high number and heterogeneity of unique operational taxonomic units (OTUs) with enrichment of additional hydrocarbon-degrading bacterial taxa (Proteiniphilum, unclassified Micrococcales, unclassified Lachnospiraceae, Sphingobium and Stenotrophomonas). Thirty-three culturable hydrocarbon-degrading microbes were isolated from the co-composting microcosms and mainly classified into Burkholderia, Sanguibacter, Pseudomonas, Bacillus, Rhodococcus, Lysinibacillus, Microbacterium, Brevibacterium, Geobacillus, Micrococcus, Arthrobacter, Cellulimicrobacterium, Streptomyces Dietzia,etc,. that was additionally affirmed with the presence of catechol 2,3-dioxygenase gene. Finally, enhanced in situ degradation of total (49%), LMW (>75%) and HMW PAHs (>35%) was achieved with an enriched bacterial consortium of these microbes. Overall, these findings suggests that co-composting treatment of crude oil sludge with animal manures selects for intrinsically diverse bacterial community, that could be a driving force behind accelerated bioremediation, and can be exploited for engineered remediation processes.

Fundamental Insights into Free-Radical Polymerization in the Presence of Catechols and Catechol-Functionalized Monomers

Fundamental Insights into Free-Radical Polymerization in the Presence of Catechols and Catechol-Functionalized Monomers

SiO2-coated molecularly imprinted sensor based on Si quantum dots for selective detection of catechol in river water

Selectivity is an important goal to the final analysis of targets. But for silicon quantum dots (Si QDs), a kind of QDs with low-toxic from a wide range of sources, the selective detection is mainly through the special force between Si QDs and targets. Yet it is necessary to find a way to realize the selective detection for more common target analysis. Herein, the molecularly imprinted polymers based on Si QDs (Si QDs@SiO2 @MIPs) was successfully prepared for selective detection of catechol (CT). Si QDs were firstly modified with 3-Aminopropyltriethoxysilane (APTES), the template molecule CT was effectively contacted with Si QDs after modifications, under the action of cross-linking agent tetraethyl orthosilicate (TEOS), Si QDs@SiO2 @MIPs were synthesized through the sol-gel method. Si QDs@SiO2 @MIPs displayed a strong fluorescent emission at 447 nm and were quenched in the presence of CT via dynamic quenching. Under optimum conditions, the relative fluorescent intensity of Si QDs@SiO2 @MIPs was gradually weakened in response to the increased CT concentrations in the range of 0.018–100 µM. A low detection limit of 0.018 µM for CT determination was obtained. This developed strategy was evaluated by detecting CT in the real river water samples. Satisfactory recoveries were obtained in the range of 97.77−101.70%. Moreover, the high-performance liquid chromatography (HPLC) method was conducted as a reference of CT detection, the results powerfully demonstrated the accuracy and feasibility of the method proposed in this work. Thus, the strategy is possibly a promising method for Si QDs to expand more target detection.

A Comprehensive Potentiometric Study of the Tartrate Complexes of Trivalent Arsenic, Antimony, and Bismuth in Aqueous Solution.

The tartrate complexes of trivalent arsenic, antimony, and bismuth were studied potentiometrically. The existing, fragmentary data on the antimony/l-(+)-tartrate system were confirmed. Nine complexes of arsenic and bismuth with optically active, racemic, and meso-tartrate, as well as complexes of antimony with meso-tartrate, were newly identified, and their formation constants computed. Difficulties arising from the poor stability of the arsenic complexes and precipitation in the Sb(III)/meso-tartrate system were overcome by titrating at very high concentrations [As(III) systems] and using an auxiliary ligand [Sb(III) in the presence of catechol]. All data were obtained at 25.0 °C and at constant ionic strength [0.1 mol L-1 for Sb(III) and Bi(III) complexes and 1 mol L-1 for As(III) complexes]. Speciation diagrams of all systems at millimolar concentrations were computed on the basis of the newly obtained constants and the results discussed.

Evaluation of Amyloid Polypeptide Aggregation Inhibition and Disaggregation Activity of A-Type Procyanidins

The number of people worldwide suffering from Alzheimer’s disease (AD) and type 2 diabetes (T2D) is on the rise. Amyloid polypeptides are thought to be associated with the onset of both diseases. Amyloid-β (Aβ) that aggregates in the brain and human islet amyloid polypeptide (hIAPP) that aggregates in the pancreas are considered cytotoxic and the cause of the development of AD and T2D, respectively. Thus, inhibiting amyloid polypeptide aggregation and disaggregation existing amyloid aggregates are promising approaches in the therapy and prevention against both diseases. Therefore, in this research, we evaluated the Aβ/hIAPP anti-aggregation and disaggregation activities of A-type procyanidins 1–7 and their substructures 8 and 9, by conducting structure–activity relationship studies and identified the active site. The thioflavin-T (Th-T) assay, which quantifies the degree of aggregation of amyloid polypeptides based on fluorescence intensity, and transmission electron microscopy (TEM), employed to directly observe amyloid polypeptides, were used to evaluate the activity. The results showed that catechol-containing compounds 1–6 exhibited Aβ/hIAPP anti-aggregation and disaggregation activities, while compound 7, without catechol, showed no activity. This suggests that the presence of catechol is important for both activities. Daily intake of foods containing A-type procyanidins may be effective in the prevention and treatment of both diseases.

Catechol‐ and Phenol‐Containing Thio‐Schiff Bases: Synthesis, Electrochemical Properties and Biological Evaluation

AbstractA number of novel catechol‐ and phenol‐containing Schiff bases with thiophenol or mercaptobenzimidazole groups have been synthesized. Electrochemical studies of the target compounds were carried out in order to establish the primary centres involved in redox reactions, and the mechanism of oxidative transformations. The antioxidant activities of the compounds were determined using different assays. Compounds combining the catechol group with the mercaptobenzimidazole or benzothiazoline cycles exhibit more pronounced antioxidant activity in the concerning tests. However, a significant promoting effect on the process of lipid peroxidation of rat brain homogenates was found in the presence of catechols. Antibacterial and cytotoxic effects of Schiff bases can be caused by the possibility of ROS and o‐benzoquinones generation. It was established that some compounds have a moderate bacteriostatic effect against Staphylococcus aureus strains. Schiff bases with catechol and heterocyclic groups exhibit a good antiproliferative activity (IC50<10 μM) towards MCF‐7, HTC‐116 and A549 cell lines.

Functionalization of polylactic acid thin films via polydopamine-assisted chelation of copper (II) ions for antibacterial applications

Polylactic acid (PLA) is a biodegradable polymer, which has been widely investigated for use in biomedical and packaging applications due to its excellent biodegradability, biocompatibility, non-toxicity, low cost, good stability, and thermal processability. In this work, PLA was functionalized to improve the membrane’s hydrophilicity and impart antimicrobial activity by simultaneously depositing polydopamine (PDA) and chelating Cu2+ metal ions on the membrane surface. Pristine PLA films were modified via one-pot dip coating method using dopamine-copper (II) solution at different coating times (6, 12, 24 h). FTIR analysis confirmed the deposition of PDA on the modified membranes (PLA/PDA/Cu) as indicated by the presence of catechol and amine moieties on the samples. TGA results revealed the degradation of the same functional groups on PLA/PDA/Cu. The hydropilicity of PLA was significantly reduced upon coating with PDA as indicated by the decrease in the membrane’s contact angle from 96.5 ± 5.3° to 56.2 ± 4.7°. SEM images and EDS results clearly showed that copper particles were deposited on the PLA/PDA/Cu membranes (atomic % ~ up to 0.88) and coating with PDA did not alter the porous structure of the pristine PLA film. Results also demonstrated that the concentration of copper immobilized on the modified membranes increased with longer coating; thus, offering a way of tailoring the metal concentration on the membrane for its specific use. PLA/PDA/Cu membranes showed antibacterial property against the B. subtilis, which could be attributed to the chelation of Cu2+ ions with the catechol moiety of the PDA coating.

Unraveling the Bioactive Profile, Antioxidant and DNA Damage Protection Potential of Rye (Secale cereale) Flour.

Six different solvents were used as extraction medium (water, methanol, ethanol, acidified methanol, benzene and acetone) to check their phenolics extraction efficacy from flour of two rye cultivars. Rye extracts with different solvents were further analyzed for the estimation of phytochemicals and antioxidant properties. Different tests (TPC, TAC, DPPH, FRAP, ABTS, RPA and CTC) were performed to check the antioxidant properties and tannin contents in extracts. A bioactive profile of a rye cultivar indicated the presence of total phenolic compounds (0.08–2.62 mg GAE/g), total antioxidant capacity (0.9–6.8 mg AAE/g) and condensed tannin content (4.24–9.28 mg CE/100 g). HPLC was done to check phenolics in rye extract with the best solvent (water), which indicated the presence of Catechol (91.1–120.4 mg/100 g), resorcinol (52–70.3 mg/100 g), vanillin (1.3–5.5 mg/100 g), ferulic acid (1.4–1.5 mg/100 g), quercetin (4.6–4.67 mg/100 g) and benzoic acid (5.3 mg/100 g) in rye extracts. The presence of DNA damage protection potential in rye extracts indicates its medicinal importance. Rye flour could be utilized in the preparation of antioxidant-rich health-benefiting food products.

ZIF-L Derived Bimetallic N-Doped Porous Carbon-Prussian Blue Composite as Efficient Catechol Electrochemical Sensor

The development of effective and accurate catechol (CC) electrochemical sensors is critical for environment and life health perspectives. A facile pyrolysis of 2D bimetallic (Zn/Co) zeolitic imidazolate framework (Zn/Co-ZIF-L) was employed to prepare Zn and Co nanoparticles encapsulated in N-doped porous carbon (Zn/Co@NPC). Prussian blue (PB) was synthesized in situ via the co-precipitation of ferricyanide ([Fe(CN)6]3−) and iron (II) ion originated from the reduction of Fe3+ by Zn/Co@NPC and then served as the main active substance of CC detection. The morphology and composition of the final composite Zn/Co@NPC-PB were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). The Zn/Co@NPC-PB modified glass carbon electrode (GCE) exhibits two concentration linear ranges of 4.13 μM − 1.08 mM (R2 = 0.999) and 1.08 mM−11.82 mM (R2 = 0.999) for CC electrochemical detection with a limit of detection 1.05 μM (S/N = 3). At the same time, the Zn/Co@NPC-PB/GCE shows great selectivity to electrochemical oxidation behavior of CC in presence of 20 folds dihydroxybenzene interferents such as hydroquinone and resorcinol. Furthermore, it showed a long-term stability and near 100% recovery for the detection of a real sample in Yellow River water.

Enhancement of Iron-Based Photo-Driven Processes by the Presence of Catechol Moieties

Photo-induced Advanced Oxidation Processes (AOPs) using H2O2 or S2O82− as radical precursors were assessed for the abatement of six different contaminants of emerging concern (CECs). In order to increase the efficiency of these AOPs at a wider pH range, the catechol organic functional compound was studied as a potential assistant in photo-driven iron-based processes. Different salinity regimes were also studied (in terms of Cl− concentration), namely low salt water (1 g·L−1) or a salt–water (30 g·L−1) matrix. Results obtained revealed that the presence of catechol could efficiently assist the photo-Fenton system and partly promote the photo-induced S2O82− system, which was highly dependent on salinity. Regarding the behavior of individual CECs, the photo-Fenton reaction was able to enhance the degradation of all six CECs, meanwhile the S2O82−-based process showed a moderate enhancement for acetaminophen, amoxicillin or clofibric acid. Finally, a response-surface methodology was employed to determine the effect of pH and catechol concentration on the different photo-driven processes. Catechol was removed during the degradation process. According to the results obtained, the presence of catechol in organic macromolecules can bring some advantages in water treatment for either freshwater (wastewater) or seawater (maritime or aquaculture industry).

A tough polysaccharide-based cell-laden double-network hydrogel promotes articular cartilage tissue regeneration in rabbits

Hydrogels used for cartilage tissue engineering purposes must be designed to mimic the biological and physical features of the native extracellular matrix (ECM). Here, we developed three different types of physical and chemical chondro-inductive hydrogels with the controlled drug release ability based on sulfated alginate (SAlg) and chitosan (CS). Bioconjugation of catechol to SAlg (SAlg-Cat) resulted in formation of SAlg-Cat/CS hydrogels with higher mechanical stability than physical SAlg/CS hydrogel. In the chemical double-network hydrogel (DN/SAlg-Cat), the presence of catechol and amine groups within the network resulted in dynamic and reversible bonding with energy dissipation. Our DN/SAlg-Cat hydrogel with initial compressive modulus of 34.86 kPa exhibited adequate compressive strength (421.45 kPa), toughness (89.69 kJ/m3), ability to self-heal and recoverability, which could be exceptional for utilizing in a load-bearing tissue like cartilage. Among hydrogels, the DN/SAlg-Cat hydrogel displayed less degradation rate (6.81%) and higher mechanical stability (81% retention of stiffness) in the presence of lysozyme (15 μg/mL) during 21 days. Incorporation of the sulfate and catechol groups within these hydrogels mediated the sustained release of TGF-β1 and kartogenin (KGN) chondrogenic agents, and resulted in proper chondrogenesis of the encapsulated mesenchymal stem cell (MSC) and chondrocyte (CH) co-culture. The catechol-enriched hydrogels (SAlg-Cat/CS and DN/SAlg-Cat) showed better regeneration of full-thickness articular defects in rabbits after 12 weeks due to the high affinity of the catechol group for cell adhesion, tissue integration, and immobilization of the biological factors. Our results demonstrated a role for a biomimetic microenvironment in efficient chondrogenesis.

Persistent Free Radicals from Low-Molecular-Weight Organic Compounds Enhance Cross-Coupling Reactions and Toxicity of Anthracene on Amorphous Silica Surfaces under Light.

Polycyclic aromatic hydrocarbon (PAH) contamination has raised great environmental concerns, while the effects of low-molecular-weight organic compounds (LMWOCs) on PAH photodegradation at amorphous silica (AS)/air interfaces have been largely ignored. In this study, the phototransformation of anthracene (ANT) at amorphous silica (AS)/air interfaces was investigated with the addition of LMWOCs. ANT removal was attributed to •OH attacking and the energy transfer process via 3ANT*. Light irradiation induced the fractured ≡SiO• or ≡Si• generation on AS surfaces, which could react with absorbed H2O and O2 to generate •OH and further yield a series of hydroxylated products of ANT. The presence of citric acid and oxalic acid improved •OH generation and enhanced ANT removal by 1.0- and 2.2-fold, respectively. For comparison, the presence of catechol and hydroquinone significantly decreased ANT removal and produced coupling products. The results of density functional theory calculations suggest that persistent free radicals (PFRs) on AS surfaces from catechol or hydroquinone after •OH attacking prefer to cross-couple with ANT via C-C bonding rather than self-couple. Dianthrone and cross-coupling products might possess higher ecotoxicity, while hydroxylated products were less ecotoxic than their parent compounds based on Ecological Structure Activity Relationships (ECOSAR) estimation. The results of this study revealed the potential ecotoxicity of PAH-adsorbed particulates coexisting with LMWOCs and also provided a new insight into PAH transformation through PFR pathways.

Transformation and detoxification of sulfamethoxazole by permanganate (Mn(VII)) in the presence of phenolic humic constituents

In this study, the transformation and detoxification of sulfamethoxazole (SMX, a frequently detected antibiotic in the environments) by permanganate (Mn(VII)) in the presence of model humic constituents (HCs) was evaluated. SMX that hardly react to Mn(VII) was rapidly degraded by Mn(VII) in the presence of catechol (CAT) at pH 5–7, while resorcinol (RES) and hydroquinone (HQ) showed negligible accelerating effect. This enhancing effect was attributed to the 1,4-nucleophilic addition between SMX and o-benzoquinone (o-BQ), an important intermediate generated from oxidation of CAT by Mn(VII). Both Mn(VII) and in-situ formed manganese dioxide (Mn(IV)) accounted for the generation of o-BQ. The experimental results indicated that alkaline condition and excess Mn(VII) were unfavorable for the degradation of SMX by inhibiting the formation of o-BQ. Bioluminescence inhibition assay with vibrio fischeri and data simulated by EPI software showed that the transformation products of SMX retained much less acute toxicity than the parent SMX. Furthermore, the effect of several other HCs structurally related to CAT on the abatement of SMX was explored. The result suggested that the accelerating effect of CAT analogues largely depended on the type of substituent group in para position. Meanwhile, the concentration of manganese in the supernatant was lower than WHO criteria (0.1 mg/L). This work provided a novel and efficiency strategy to detoxify SMX in water treatment.

Evaluating metabolic potential of Thauera sp. M9 for the transformation of 4-chloroaniline (4-CA)

Abstract Thauera sp. M9, was isolated after enrichment of microbial diversity in nitrogen free mineral salt medium (NFMSM) supplemented with 300 mg/l of 4-chloroaniline (4-CA). The isolate M9 was able to achieve complete degradation of 300 mg/l 4-CA supplement to NFMSM, after 30 h incubation. In addition to 4-CA, isolate M9 was able to achieve complete degradation of 300 mg/l 3-chloroaniline (3-CA), 21% degradation of 300 mg/l 2-chloroaniline (2-CA), and complete transformation of 50 mg/l of 3, 4-dichloroaniline (3, 4-DCA), was observed only in the presence of 0.02% (w/v) yeast extract (YE) supplement to NFMSM. The presence of catechol 2, 3-dioxygenase (C23O) activity in cell free extract and detection of 4-chlorocatechol (4-CC); 2-hydroxy muconic semialdehyde (2-HMS) in biologically transformed samples by mass spectroscopy (MS) analysis indicated to meta-cleavage of the aromatic ring. A plug flow reactor (PFR) was developed using polyurethane foam (PUF) and refractory brick pieces (RBP) as immobilization matrix. The treatment of simulated effluent supplemented with 300 mg/l 4-CA through PFR, resulted in 88% transformation of 4-CA and 70% lowering of chemical oxygen demand (COD). These observations suggest that Thauera sp. M9 could be a potential inoculum for developing bioremediation protocols for waste rich in chloroanilines (CAs).

The two facets of the synergic effect of amine cation and catechol on the adhesion of catechol in underwater conditions

Many factors govern the underwater adhesion of mussels, among which the synergic effect of charged amino group and catechol moiety in mussel foot-byssus proteins has been discovered recently. Here we show that although very important, spatial proximity might not be the prerequisite for the synergic effect between amino and catechol groups in underwater adhesion. By designing probes grafted with monomer integrated with both groups and with monomers carrying the two groups separately, we revisted the synergic effect at nanoscale level. It is found that the synergic effect has two facets: first, the presence of both groups enable stronger adhesion in electrolyte solutions than the presence of catechols alone, and this effect does not require catechols and amine cations to be next to each other in space. Second, only when the catechol and cation are paired and next to each other, the adhesion force could be further enhanced in low pH solutions, which means the dependence of synergic effect on the spatial proximity of catechols and amine cations is conditional to the acidity of the electrolyte solution. We reason that besides the already discovered effect in protecting catechol from oxidation, acid condition contributes to underwater adhension by interfering with the formation of the hydration layer, which helps the eviction of absorbed cations and the coordination of catechol sequentially when the catechol and amino cation are spatially next to each other.