μM Fe2 Research Articles

Identification and determination of usnic acid and fatty acid from various lichen species in arequipa, Peru, as well as antibacterial and antioxidant capacity

Seven species of lichens such us Umbilicaria aff. calvescens, Hypotrachyna enderythraea, Punctelia graminicola, Cladonia chlorophaea, Xanthoparmelia farinose, Psiloparmelia distincta (rock and tree substrates; rs and ts), and Usnea durietzii were collected from the province of Arequipa - Peru. Their usnic acid (UA) and fatty acid (FA) amounts in methanol-acetone were determined by High-performance liquid chromatography with diode-array detection (HPLC-DAD) and Gas chromatography-flame ionization detector (GC-FID). The antimicrobial activities of these extracts were evaluated against Staphylococcus aureus ATCC strains (43300, 29213, 25923 and 700699), Escherichia coli strains (O157:H7 and ATCC 10536), Salmonella enterica sv typhimurium ATCC 14028, Candida albicans ATCC 90028 and Candida. tropicalis ATCC 750T. In addition, antioxidant capacity was also studied by Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, 2,2-Azino-bis-3-ethylbenzothiazoline-6-sulfonic Acid (ABTS) radical cation and Ferric Reducing Antioxidant Power (FRAP) assays. The UA contents in all the studied lichen species varied between 0.017 and 0.304 %. Among all the tested extracts, Usnea durietzii had the highest total FA concentration (5.81 mg/g). P. distincta (rs) was active against S. aureus strains (MIC = 0.02–0.2 mg/mL) as well as C. albicans (MIC = 4 mg/mL) and C. tropicalis (MIC = 3 mg/mL). P. distincta (ts) displayed moderate total phenol content (TPC = 29.1 ± 1.6 mg GAE/g) and antioxidant capacity evidenced by scavenging DPPH (IC50 = 1.45 ± 0.03 mg/mL) and ABTS (18.2 ± 0.2 mg TE/g) radicals, but it showed high values of FRAP (1953 ± 87 μM Fe2+/g). Our findings indicate that P. distincta (rs) could be considered as a potential antimicrobial metabolites source whereas P. distincta (ts) and Puntelia graminicole for polyphenols with antioxidant compound.

Characterization of a novel antioxidant exopolysaccharide from an intestinal-originated bacteria Bifidobacterium pseudocatenulatum Bi-OTA128

Microbial exopolysaccharides (EPSs) have attracted extensive attention for their biological functions in antioxidant activities. In this study, we characterized a novel EPS produced by Bifidobacterium pseudocatenulatum Bi-OTA128 which exhibited the highest antioxidant capacity compared to nine other ropy bacterial strains, achieving 76.50 % and 93.84 % in DPPH· and ABTS·+ scavenging activity, and ferric reducing power of 134.34 μM Fe2+. Complete genomic analysis identified an eps gene cluster involved in the EPS biosynthesis of Bi-OTA128 strain, which might be responsible for its ropy phenotype. The EPS was then isolated and purified by a DEAE-Sepharose Fast Flow column. A single elution part EPS128 was obtained with a recovery rate of 43.5 ± 1.78 % and a total carbohydrate content of 93.6 ± 0.76 %. Structural characterization showed that EPS128 comprised glucose, galactose, and rhamnose (molar ratio 4.0:1.2:1.1), featuring a putative complex backbone structure with four branched chains and an unusual acetyl group at O-2 of terminal rhamnose. Antioxidant assay in vitro indicated that EPS128 exhibited antioxidant potential with 50.52 % DPPH· and 65.40 % ABTS·+ scavenging activities, reaching 54.3 % and 70.44 % of the efficacy of standard Vitamin C at 2.0 mg/L. Furthermore, EPS128 showed protective effects against H2O2-induced oxidative stress in HepG2 cells by reducing cellular reactive oxygen species (ROS) and increasing cell viability. These findings present the first comprehensive report of an antioxidant EPS from B. pseudocatenulatum, highlighting its potential as a natural antioxidant for applications in the food industry and clinical settings.

Efficient degradation of emerging pollutant-malachite green in water by pulsed discharge plasma on water surface in cooperation with Fe2+/PMS

The effective and rapid treatment of emerging pollutants in water is an essential solution to the pollution of water environment. The emerging pollutant-malachite green (MG) wastewater was treated using pulsed discharge plasma on water surface system (WSP) combining Fe2+/PMS. Compared with WSP alone, the addition of 125 μM Fe2+ and 0.5 mM peroxymonosulfate (PMS) in WSP could enhance the degradation efficiency and energy efficiency of MG by 32.8% and 9.7% respectively, with the synergistic factor of up to 2.056. UV–Vis absorption spectra and mineralization further demonstrated the synergistic effect. When the peak voltage and air flow rate were 22 kV and 0.7 L/min, the degradation efficiency and kinetic constant of MG could reach 97.9% and 0.259 min−1, respectively. MG degradation with high conductivity (1000 μS/cm) by WSP + Fe2+/PMS not only exhibited the better purification effect, but also could maintain the faster reaction rate. The active species involved in the degradation of MG in WSP + Fe2+/PMS system were mainly ·OH, SO4·−, O2·− and e*−. Furthermore, H2O2 and O3 also have a certain oxidizing effect on MG. Cl−, SO42−, HCO3− and humic acid (HA) could inhibit MG degradation to some extent, but still removed more than 80% of MG in water. The WSP + Fe2+/PMS reaction system was suitable for the treatment of other emerging pollutants in water. The results of LC-MS analysis revealed that the N-demethylation reaction and decomposition of conjugated structure were the important pathways for MG degradation. The H2O2 and acidic liquid environment provided by WSP laid the foundation for the formation of Fenton, and the introduced Fe2+ could fully undergo the Fenton and activation reaction with H2O2 and a small amount of PMS in the liquid phase, which enhanced the generation of active species, especially ·OH.

Heterologous expression and characterization of a dye-decolorizing peroxidase from Ganoderma lucidum, and its application in decolorization and detoxifization of different types of dyes.

Dye-decolorizing peroxidases (DyPs) belong to a novel superfamily of heme peroxidases that can oxidize recalcitrant compounds. In the current study, the GlDyP2 gene from Ganoderma lucidum was heterologously expressed in Escherichia coli, and the enzymatic properties of the recombinant GlDyP2 protein were investigated. The GlDyP2 protein could oxidize not only the typical peroxidase substrate ABTS but also two lignin substrates, namely guaiacol and 2,6-dimethoxy phenol (DMP). For the ABTS substrate, the optimum pH and temperature of GlDyP2 were 4.0 and 35°C, respectively. The pH stability and thermal stability of GlDyP2 were also measured; the results showed that GlDyP2 could function normally in the acidic environment, with a T50 value of 51°C. Moreover, compared to untreated controls, the activity of GlDyP2 was inhibited by 1.60 mM of Mg2+, Ni2+, Mn2+, and ethanol; 0.16 mM of Cu2+, Zn2+, methanol, isopropyl alcohol, and Na2EDTA·2H2O; and 0.016 mM of Fe2+ and SDS. The kinetic constants of recombinant GlDyP2 for oxidizing ABTS, Reactive Blue 19, guaiacol, and DMP were determined; the results showed that the recombination GlDyP2 exhibited the strongest affinity and the most remarkable catalytic efficiency towards guaiacol in the selected substrates. GlDyP2 also exhibited decolorization and detoxification capabilities towards several dyes, including Reactive Blue 19, Reactive Brilliant Blue X-BR, Reactive Black 5, Methyl Orange, Trypan Blue, and Malachite Green. In conclusion, GlDyP2 has good application potential for treating dye wastewater.

Heterogeneous activation of self-generated H2O2 by Pd@UiO-66(Zr) for trimethoprim degradation: Efficiency and mechanism

The Fenton reaction is recognized as an effective technique for degrading persistent organic pollutants, such as the emerging pollutant trimethoprim (TMP). Recently, due to the excellent reducibility of active hydrogen ([H]), Pd–H2 has been preferred for Fenton-like reactions and the specific H2 activation of Pd-based catalysts. Herein, a heterogeneous Fenton catalyst named the hydrogen-accelerated oxygen reduction Fenton (MHORF@UiO-66(Zr)) system was prepared through the strategy of building ships in the bottle. The [H] has been used for the acceleration of the reduction of Fe(III) and self-generate H2O2. The systematic characterization demonstrated that the nano Pd0 particle was highly dispersed into the UiO-66(Zr). The results found that 20 mg L−1 of TMP was thoroughly degraded within 90 min in the MHORF@UiO-66(Zr) system under conditions of initial pH 3, 30 mL min−1 H2, 2 g L−1 Pd@UiO-66(Zr) and 25 μM Fe2+. The hydroxyl radical as well as the singlet oxygen were evidenced to be the main reactive oxygen species by scavenging experiments and electron spin resonance. In addition, both reducing Fe(III) and self-generating H2O2 could be achieved due to the strong metal-support interaction (SMSI) between the nano Pd0 particles and UiO-66(Zr) confirmed by the correlation results of XPS and calculation of density functional theory. Finally, the working mechanism of the MHORF@UiO-66(Zr) system and the possible degradation pathway of the TMP have been proposed. The novel system exhibited excellent reusability and stability after six cyclic reaction processes.

Mango Leaves (Mangifera indica)-Derived Highly Florescent Green Graphene Quantum Dot Nanoprobes for Enhanced On-Off Dual Detection of Cholesterol and Fe2+ Ions Based on Molecular Logic Operation.

In the present study, we have engineered a molecular logic gate system employing both Fe2+ ions and cholesterol as bioanalytes for innovative detection strategies. We utilized a green-synthesis method employing the mango leaves extract to create fluorescent graphene quantum dots termed "mGQDs". Through techniques like HR-TEM, i.e., high-resolution transmission electron microscopy, Raman spectroscopy, and XPS, i.e., X-ray photoelectron spectroscopy, the successful formation of mGQDs was confirmed. The photoluminescence (PL) characteristics of mGQDs were investigated for potential applications in metal ion detection, specifically Fe2+ traces in water, by using fluorescence techniques. Under 425 nm excitation, mGQDs exhibited emission bands at 495 and 677 nm in their PL spectrum. Fe2+-induced notable quenching of mGQDs' PL intensity decreased by 97% with 2.5 μM Fe2+ ions; however, adding 20 mM cholesterol resulted in a 92% recovery. Detection limits were established through a linear Stern-Volmer (S-V) plot at room temperature, yielding values of 4.07 μM for Fe2+ ions and 1.8 mM for cholesterol. Moreover, mGQDs demonstrated biocompatibility, aqueous solubility, and nontoxicity, facilitating the creation of a rapid nonenzymatic cholesterol detection method. Selectivity and detection studies underscored mGQDs' reliability in cholesterol level monitoring. Additionally, a molecular logic gate system employing Fe2+ metal ions and cholesterol as a bioanalyte was established for detection purposes. Overall, this research introduces an ecofriendly approach to craft mGQDs and highlights their effectiveness in detecting metal ions and cholesterol, suggesting their potential as versatile nanomaterials for diverse analytical and biomedical applications.

Sulfite activation by non-thermal plasma coupled with Fe2+ for ibuprofen degradation: In-depth insight into activation energy barrier and mechanism

This paper underscores the pivotal role of Fe2+ in influencing the degradation of ibuprofen (IBP) within non-thermal plasma (NTP) activated sulfite (S) system. At 200 μM Fe2+ dosage, the rate of IBP degradation can attain 94.8 %. In contrast to the absence of Fe2+, there was a 43.1 % increase in the rate of IBP degradation. The quenching experiment indicates that SO4·− and ·OH constitute the principal species in the system. This phenomenon predominantly stems from the Fenton-like reaction, expediting the conversion of H2O2 to ·OH. Additionally, the activation of sulfite by the Fe2+ and NTP promotes a concurrent increase in SO4·−. The introduction of Fe2+ results in the detection of a substantial quantity of ·OH and SO4·− in the system, validated through direct detection and electron spin resonance (ESR) signals. According to the density functional theory (DFT), the energy barrier of NTP/Fe2+ activation sulfite is lower than that of NTP system activation. By comparing the specific degradation pathways of NTP/S/Fe2+ and NTP/S systems, it can be concluded that the degradation of pollutants in NTP/S/Fe2+ system mainly depends on the action of active free radicals (·OH and SO4·−), while that in NTP/S system is mainly due to non-free radicals.

Ultra-sensitive Tb3+/G-quadruplex fluorescence detection of oxidative DNA damage coupled with DNA glycosylase

Development of simple, sensitive and rapid sensing strategy for DNA damage induced by chemical reagents is urgent demand. In this assay, a Tb3+/G-quadruplex fluorescence system was proposed for the sensitive detection of DNA damage induced by Fenton reaction. The specific guanine-rich oligonucleotides can form G-quadruplex induced by Tb3+, leading to an enhancement of Tb3+ emission due to energy transfer from guanine to Tb3+. After a DNA damage reaction with Fenton reagents, an obvious fluorescence decrease was observed due to the structure change of Tb3+/G-quadruplex. which was also confirmed by polyacrylamide gel electrophoresis and circular dichroism. The Fe2+-mediated Fenton reaction with as low as 0.01 μM Fe2+ and 0.04 μM H2O2 induced oxidative DNA damage can be detected. Additionally, the human 8-oxoguanine DNA glycosylase (hOGG 1) was introduced to amplify DNA oxidation damage, by converting DNA oxidative nucleobases to strand break. Over 30-fold lower detection limit of 0.3 nM Fe2+ and 1.2 nM H2O2 was achieved. Alternative specific DNA damage or other DNA repair enzymes produced much less fluorescence decrease, demonstrating its good selectivity. It shows the potential to become a universal screening tool for the rapid and sensitive assessment of the genotoxicity of the overwhelming number of chemicals in environment.

Mechanism of ferrous ions reversibly inhibiting of oxidase-Like activity of Co3O4 nanowires and its application in horticultural fertilizer analysis

Nanozymes are becoming substitutes of some natural enzymes due to their excellent properties, however, little attention has been paid to the catalytic mechanisms and especially inhibition mechanism of nanozymes, which impeded advancement in nanozymes and their wide application including bioanalysis. Herein, non-toxic filamentous virus, M13 phage templated Co3O4 nanowires (NWs) was facilely prepared, which exhibits excellent oxidase (OXD)-like activity and catalytic efficiency. The catalytic mechanism of OXD-like is oxygen vacancies, confirmed by high resolution X-ray photoelectron spectrum of O 1 s, electron paramagnetic resonance spectra and reactive oxygen species scavenging experiments. The substrate of 3,3′,5,5′-tetramethylbenzidine (TMB) for OXD-like is oxidized into blue ox-TMB, and then turned to yellow diimine, depending on TMB concentration and incubation time. Then the mechanism of ferrous ions (Fe2+) inhibition of the oxidase-like activity of Co3O4 NWs was uncovered that Fe2+ competes with TMB for oxygen vacancies. The inhibition is reversible with the type of hybrid of competitive inhibition and non-competitive inhibition with the inhibition constants (KI and KI') of 0.134 mM and 1.012 mM, respectively. Finally, on the basis of the inhibitory effect, a fast, selective and sensitive Fe2+ colorimetric analysis was proposed with two linear parts and a limit of detection of 0.21 μM Fe2+ (S/N = 3), which is applicable to detect Fe2+ in horticultural fertilizers. This study may offer a new strategy for the in-depth study of inhibition mechanism of other nanozymes, which would extend the scope of nanozyme-based biosensing.

Phytochemical Screening and Antioxidant Potential of Methanol Extract of Triumfetta cordifolia A. Rich. (Malvaceae) Leaves

Triumfetta cordifolia is a medicinal plant that has been widely utilized in Africa for its therapeutic properties in treating various ailments. The purpose of this research was to investigate phytochemicals and in vitro antioxidant activity of the leaf extract of T. cordifolia. Standard methods were employed to conduct qualitative phytochemical screening of the plant extract. This study used the DPPH (1, 1diphenyl-2-picryl hydrazyl) radical scavenging and ferric reducing antioxidant power method to assess antioxidant activity. Phytochemical analysis of T. cordifolia leaves indicated the existence of saponins, tannins, terpenoids, cardiac glycosides, alkaloids, flavonoids but no anthraquinones. In the DPPH scavenging test, the IC50 value of the methanolic extract was discovered to be 1.29 µg/mL, and the standard reference value for ascorbic acid was 2.14 µg/mL. The leaf extract of T. cordifolia displayed stronger inhibition of DPPH activity, showing a higher potency than ascorbic acid. The DPPH scavenging activity was also shown to increase with concentration. In FRAP assay, the T. cordifolia leaf extract and the ascorbic acid revealed reducing power of 71.01±0.15 and 548.39±1.62 μM Fe2+ per mg of extract, respectively. The FRAP assay demonstrated that ascorbic acid exhibited greater antioxidant activity than the leaf extract of T. cordifolia. The presence of flavonoids and phenols in T. cordifolia leaves may account for the observed antioxidant activity. In conclusion, the study's findings suggest that that T. cordifolia leaf extract could be a source of lead compounds with promising antioxidant activity.

Hydrothermal synthesis of B, S, and N-doped carbon quantum dots for colorimetric sensing of heavy metal ions.

In this study, glucose was used as the carbon source to synthesize carbon quantum dots (CQDs) and also aimed to synthesize CQDs doped with heteroatoms such as sulphur, nitrogen, and boron to enhance their functionality. The obtained material has been characterized by several techniques. According to FL analysis, the highest peaks for CQD, N-CQD, B-CQD, and S-CQD were determined as 432 nm (ex 350), 425 (ex 350), 430 nm (ex 340 nm), and 436 nm (ex 340 nm), respectively. FTIR spectra showed different characteristic peaks for CQD, and the FTIR results show that CQDs have a unique structure. According to TEM analysis, the morphology of all CQDs was found to be spherical and monodisperse with average sizes in the range of 5-7 nm. The characterization results of CQDs show that the addition of heteroatoms changes the properties of CQDs. The synthesized CQDs were also tested as colorimetric sensors for the detection of heavy metals. It was observed that CQDs detected Fe3+ metal ions, B-CQD and S-CQD detected Fe3+ and Ag+ metal ions, and N-CQDs detected Ca2+ metal ions. Sensor studies were performed for all CQDs and linear plots were obtained against metal concentrations in the range of 0.06-1.23 μM. LOD values for CQD, N-CQD, S-CQD, and B-CQD were calculated as 0.187 μM (Fe3+), 0.391 μM (Ca2+), 0.224 μM (Fe3+)-0.442 μM (Ag+), and 0.182 μM (Fe3+)-0.174 μM (Ag+), respectively. The results show that the addition of B, N, and S atoms to CQDs plays a role in the improvement and modification of colorimetric sensor properties and has the potential to be used in sensor applications for the detection of heavy metals in areas such as the environment and health.

Phytochemical Screening and Antioxidant Activities of Geniotrigona thoracica Propolis Extracts Derived from Different Locations in Malaysia

Propolis, a natural resinous substance secreted by bees, has garnered considerable interest due to its diverse bioactive compounds and potential health benefits. Nevertheless, the phytochemical composition of propolis exhibits significant variation, influenced by multiple factors including geographical region, and botanical origin. These determinants exert profound effects on the distinctive properties and biological diversities of propolis. This study aimed to investigate the phytochemical composition and antioxidant activities of Geniotrigona thoracica propolis extracts collected from three apiary sites, designated as apiary A, apiary B, and apiary C, located in different regions within Selangor. The ethanolic extracts of propolis were prepared using 70% of ethanol and subjected to phytochemical screening to identify the presence of flavonoids, terpenoids, alkaloids, saponins, tannins, steroids, and cardiac glycosides, whilst the total phenolic content (TPC) and total flavonoid content (TFC) were measured using the Folin-Ciocalteu colorimetric and aluminium chloride methods, respectively. Additionally, the antioxidant activities of the propolis extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric-reducing antioxidant power (FRAP) assays. The phytochemical screening revealed the presence of flavonoids, terpenoids, alkaloids, saponins, tannins, steroids, and cardiac glycosides in all propolis extracts. The propolis from apiary A exhibited significantly higher TPC (302.21 ± 0.11 mg/mL GAE) and TFC values (99.08 ± 0.03 mg/mL QE) compared to apiary B and C. The results also indicated that propolis from apiary A possessed significantly higher antioxidant activities, with IC₅₀ value of DPPH at 25.27 μg/mL and FRAP value of 727.53 ± 0.09 μM Fe²+, in comparison to apiary B and C. A strong correlation was observed between TPC, TFC, and IC₅₀ of DPPH. This study highlights significant variations in the phytochemical compositions and antioxidant activities of propolis samples collected from different geographical and botanical sources. Further investigation is in progress to identify the specific phytochemical constituents responsible for these variations.

Influence of iron fertilizer form and concentration on bioelectricity and methane emission from hydroponic plant microbial fuel cells

This study aimed to evaluate the effect of iron form (Fe2+ and Fe3+) and concentration (0 μM, 7.5 μM, and 15 μM) on the biomass production, bioelectricity generation, and methane (CH4) emissions of hydroponic plant microbial fuel cells (H-PMFCs). Rice plants (Oryza sativa L.) were grown in H-PMFCs. During the 90 days of operation, the highest power density (PDmax) was observed in Group 7.5–15 of 949.17 mW/m3. When adding single-form iron (Fe2+ or Fe3+), the PDmax of H-PMFCs was positively correlated with iron concentration. Further, the H-PMFC feed with Fe3+ showed higher power output than the feed with Fe2+. Adding 7.5 μM Fe2+ and 15 μM Fe3+ (Group 7.5–15) showed the highest overall biomass production, including plant lengthavg/plant (89.67 ± 1.17 cm) and plant weightavg/plant (14.91 ± 0.02 g dry mass) and lowest CH4 emission (43.15 ± 2.00 g/m2). The CH4 emission test indicated that the addition of iron in rice H-PMFCs can decrease the emission of CH4 in two ways: (i) iron electron acceptors directly inhibit methanogens; (ii) iron electron acceptor enhances the electricity production ability of MFC to inhibit CH4 production. Therefore, adding 7.5 μM Fe2+ and 15 μM Fe3+ showed great potential to enhance the performance of H-PMFCs on biomass production, bioelectricity generation, and CH4 emission inhibition.

Thermo- and photosensitivity of Euterpe oleracea Mart. (Arecaceae) fruit pulp: Consequences for its antioxidant activity under basic storage conditions in the Amazon

Anthocyanins are chemically unstable, casting doubt on the antioxidant activity (AA) of Euterpe oleracea Mart. (Arecaceae) fruit pulp during storage. In this study, AA, total monomeric anthocyanin (TMAC), total flavonoid (TFC), and total phenolic contents (TPC) of this preparation after 24 h and 5 days at ambient temperature/ambient light-dark (AT/AL), ambient temperature/continuously dark (AT/CD), and under refrigeration/continuously dark (UR/CD) were compared to those of the fresh preparation. A FRAP and a DPPH assay, and a pH differential, an AlCl3 colorimetric, and Folin-Ciocalteu’s method were used. Associations between pairs of variables were determined by Pearson correlation coefficient (r). Student’s t test and one-way ANOVA with Tukey HSD were used to evaluate the data for statistically significant differences (p < 0.05). FRAP and DPPH IC50 values of the fresh preparation were 116 ± 3 μM Fe2+ equivalents/100 μg, and 57 ± 12 μg/mL, respectively. They were hardly affected after 24 h, but had decreased 4-fold and increased 2-fold, respectively, after 5 days, the least at UR/CD. TMAC, TFC, and TPC of the fresh preparation were 21 ± 4 mg Cy3GE/mg, 25 ± 4 μM RE/100 μg, and 67 ± 2 μM GAE/100 μg. The loss of AA after 5 days was accompanied by a 3- to 5-fold TMAC and TFC degradation, and a 1.5-fold TPC decrease. AA correlated better with TMAC and TFC (r ±0.7 - ±1.0) than with TPC (r ±0.4 - ±0.9). These observations are important for communities with only basic facilities for preparing and storing E. oleracea fruit pulp.

Antioxidant properties of Carallia brachiata stem bark and leaf

Carallia brachiata (Lour.) Merr. (Rhizophoraceae) had been used to treat various human disoders. This study reported antioxidant activity of C. brachiata of stem bark and leaf in various solvents. Each sample was macerated in various solvent separately. By using DPPH, ABTS, and FRAP assays, antioxidant activity was determined. The TLC method was created using dichloromethane and ethyl acetate mobile phase. The methanol extract of stem bark contained the highest TPC value (262.73 ± 1.58 mg GAE/ g extract), while the methanol extract of leaf contained the highest TFC value (45.46 ± 0.32 mg QE/ g extract). The total phenolic content of stem bark extract was higher than that of leaf extract, but the flavonoid content of the leaf extract was marginally higher. The methanol extract exhibited the highest antioxidant activity for DPPH (13.06±0.08 μg/mL), ABTS (7.19±0.08 μg/mL), and FRAP assay (155.19±0.34 μM Fe2+/g). In this research, stem bark has greater antioxidant activity than the leaf. In addition, the results of TLC profile were detailed. The TLC chromatogram indicates that C. brachiata stem bark contains more components than leaf. This study indicates that C. brachiata has a rich source of prospective antioxidants.

Novel use of ferrous iron/peroxymonosulfate for high-performance seawater desalination pretreatment under harmful algal blooms

Marine harmful algae bloom (HAB) is a growing threat to desalination plants worldwide. This work proposes ferrous iron/peroxymonosulfate (Fe2+/PMS) as a novel pretreatment technology for seawater reverse osmosis (SWRO) under HAB. Herein, Fe2+/PMS achieved a significantly higher reduction of negative charge of algae-laden seawater as compared to conventional coagulation (i.e., coagulant is Fe3+), which thereby facilitated improved flocculation to remove algal cells, turbidity and algal organics matters (AOMs), and marine Ca2+ (∼430 mg/L) could partially contribute to the enhanced coagulation performance. A new understanding of the improved coagulation efficiency achieved with Fe2+/PMS in seawater has been proposed as compared to freshwater: seawater matrix (e.g., 504 mM Cl−) was demonstrated to significantly enhance the generation of high-valent iron (FeO2+) as the main reactive intermediate instead of the long-recognized Fe3+ and free radicals, as revealed by methyl phenyl sulfoxide (PMSO) probe, radicals scavenging analysis and electron spin resonance (ESR) spectra. This new mechanism is expected to provide valuable insights for the development of more novel oxidative seawater treatment technologies. Of note, while trade-off between particles and AOMs played an important role in membrane fouling reduction by different dosages of Fe2+/PMS, Fe2+/PMS with an optimal dosage of 0.1 mM/0.05 mM achieved an unprecedentedly higher reduction (95.26%) of modified fouling index (MFI) as compared to conventional coagulation (13.28%–42.36% with 0.1–0.2 mM of Fe3+). Optical-photothermal infrared spectromicroscopy with sub-micron spatial resolution was employed to analyze membrane foulants for the first time, and Fe2+/PMS was found to mainly cause reduced cake layer resistance, which was attributed to the collectively reduced concentration of algae cells, micro-particles with sizes from 2 to 10 µm, humic substances and biopolymers. Moreover, Fe2+/PMS resulted in lower dissolved Fe3+ (<0.027 mg/L) in ultrafiltration (UF) permeate, which would make it more reliable for SWRO operation as compared to conventional coagulation. When energy-intensive dissolved air flotation (DAF) was employed to withstand HAB, Fe2+/PMS outperformed it and was instrumental in achieving reduced MFI with 56.4% lower operational cost. In this context, Fe2+/PMS would facilitate a high-performance and low-cost pretreatment technology for seawater desalination plants under HAB.

Fortification of fresh kombucha cheese with wild thyme (Thymus serpyllum L.) herbal dust and its influence on antioxidant activity

In addition to its beneficial effects on numerous acute and chronic health problems, kombucha drink (this term was used in the introduction to explain why kombucha was used as a starter culture) is characterized by the presence of a large number of acetic and lactic acid bacteria, which makes it a suitable alternative to starter culture in the production of fresh cheese. The valorization of the herbal dust, produced during the processing of tea, allows for obtaining various types of extracts rich in numerous bioactive compounds with significant antioxidant activity, why is the fortification of fresh cheese with wild thyme (Thymus serpyllum L.) highly desirable. Therefore, the aim of this study was to investigate the influence of wild thyme in the form of ground, supercritical fluid extract, and dry extract on the physicochemical properties, antioxidant activity, and sensory characteristics of functional fresh cheese after production and after ten days of storage. The greatest changes in physicochemical properties are associated with the increase in ash content and titratable acidity, but also with the decrease in pH of all samples during storage. The total phenols content increased in all samples during storage, especially in the one fortified with dry extract of wild thyme (from 1.86 ± 0.01 to 2.14 ± 0.01 mg GAE/g). The sample with wild thyme ground exhibited the highest antioxidant activity, especially ferric ion reducing antioxidant power (FRAP), which increased from 13.8 ± 0.00 to 15.10 ± 0.00 μM Fe2+/g after ten days. After ten days, the sensory characteristics remained as high as at the time of evaluation after preparation, which clarifies that the addition of wild thyme had a very good effect on consumer acceptance.

Physical, reconstitution and phenolic properties of instant drink mix prepared with Moringa oleifera leaf, raw banana and whey protein concentrate

The formulation of instant drink mix with nutritional enhancement and optimum physical properties is a challenging task. The present study was undertaken to formulate instant drink formulation (IDF) mix using the ingredients green unripe mature banana powder (GMBP), Moringa oleifera leaf powder (MLP) and whey protein concentrate powder (WPCP) as main ingredients. Different combinations of these ingredients were mixed to formulate nine different variants (treatments) of composition mixes. The developed treatments were evaluated for physical and reconstitution properties of color characteristics, water activity, bulk density, tapped density, flowability, angle of repose, foaming capacity, swelling index, hygroscopicity, water absorption capacity (WAC), water solubility index (WSI), dispersibility, and wettability. The samples were evaluated for phenolic composition and antioxidant potential. Water activity, bulk and tapped density among the samples was ranging between 0.245–0.254 aw, 0.35–0.43 g/cm3 and 0.67–0.77 g/cm3, respectively. The flowability characteristics of Carr index (CI), Hausner ratio (HR) and angle of repose were ranging between 26.20–55.51, 1.36–2.34 and 27.51–48.33, respectively, with T1 treatment having the highest values for these characteristics. Foaming capacity, swelling index and hygroscopicity was found to be 21.83–51.17 %, 3.55–10.16 % and 24.53–36.67 %, respectively. The WAC and WSI was observed to be highest in the T1 treatment with 2.55 and 76.27, respectively. Whereas, the dispersibility and wettability was found to be between 49.75–87.93 (%) and 14.15–22.46 (s), respectively. Total phenolic content (TPC), total flavonoid content (TFC) and total anthocyanin content (TAC) in the analyzed samples were ranging between 26.86 and 1740.00 mg GAE/100 g, 12.33–1880.50 mg RE/100 g and 0.27–448.83 μg C3G/g, respectively. For the antioxidant assays, the DPPH, ABTS and FRAP assay were recorded with 10.30–8.36 % inhibition, 11.85–88.07 % inhibition and 0.36–22.72 μM Fe2+/100g, respectively. Polyphenol profile and enzyme inhibition activity was analyzed among the formulated compositions.

Carob Pulp Flour Extract Obtained by a Microwave-Assisted Extraction Technique: A Prospective Antioxidant and Antimicrobial Agent

In this study, carob pulp flour (CF) extract was characterized as a high-value antioxidant and antimicrobial agent. CF extracts were obtained using microwave-assisted extraction (MAE) and optimization of the MAE process was accomplished using response surface methodology. The studied processing parameters of MAE were the liquid/solid (L/S) ratio (10–30 mL/g), extraction time (15–35 min), and ethanol concentration (40–80% w/w). The efficiency of the extraction of valuable compounds from CF was evaluated by the determining extraction yield (Y), total phenolic(TP), total flavonoid (TF) content, and antioxidant activity (DPPH, FRAP, and ABTS). The optimized MAE parameters for maximizing the yields of target compounds and antioxidant activity were the L/S ratio 30 mL/g, extraction time 35 min, and ethanol concentration 40%. The experimentally obtained values for TP, TF, DPPH, FRAP, and ABTS were 1609.92 GAE/100 g, 271.92 CE/100 g, 99.02 µMTE/g, 50.45 µM Fe2+/g, and 110.55 µMTE/g, respectively. The optimized CF extract was compared with the CF extracts obtained by conventional solid–liquid extraction (S/L) and ultrasound-assisted extraction (UAE) and was found to be more beneficial due to a 30% higher yield of TP and TF and 30–80% higher antioxidant activity. The phenolic profiles of the three extracts were quite similar. The microdilution method confirmed the antibacterial activity of MAE and S/L extracts while the antifungal effect was not observed.

Dehalococcoides mccartyi strain NIT01 grows more stably in vessels made of pure titanium rather than the stainless alloy SUS304.

Advances in many isolation studies have revealed that pure Dehalococcoides grow stably, although the large-scale pure cultivation of Dehalococcoides has yet to be established. In this study, 7 L-culturing of Dehalococcoides mccartyi strain NIT01 was first performed using vessels made of glass and stainless alloy SUS304. All batches cultured in the glass vessel successfully dechlorinated >95% of 1 mM trichloroethene (TCE) to ethene (ETH), whereas only 5 out of 13 batches cultured in the SUS304 vessel did the same. The difference in dechlorination efficiency suggested the possible inhibition of dechlorination by SUS304. Also, the strain NIT01 showed long delays in dechlorination with pieces of SUS316, steel, and a repeatedly used SUS304, but not with titanium. The repeatedly used SUS304 cracked and increased the Fe2+ concentration to ≥76 μM. Dechlorination by this strain was also inhibited with ≥1000 μM Fe2+ and ≥23 μM Cr3+ but not with ≤100 μM Ni2+ , suggesting that Cr3+ eluted from solid stainless alloys inhibited the dechlorination. Culturing in a titanium vessel instead of a stainless alloy showed the complete dechlorination of 1 mM TCE within 12-28 days with a growth yield of 2.7 × 107 cells/μmol-released Cl- , even after repeating use of the vessels six times.