Enhanced Electrocatalytic Activity of Methanol and Ethanol Oxidation in Alkaline Medium at Bimetallic Nanoparticles Electrochemically Decorated Fullerene-C60 Nanocomposite Electrocatalyst: An Efficient Anode Material for Alcohol Fuel Cell Applications

Direct alcohol fuel cells (DAFCs) have been recently playing a pivotal role in electrochemical energy sources and portable electronics. Research in DAFCs has proceeded to engage major attention due to their high catalytic activity, long-term stability, portability, and low cost. Herein, we present a facile surfactant-free route to anchor bimetallic Pd−W nanoparticles supported fullerene-C₆₀ catalyst (Pd-W@Fullerene-C₆₀) for high-performance electrooxidation of alcohols (methanol & ethanol) for DAFCs applications. Structural, elemental composition, and morphological analysis of the proposed catalyst were carried out using UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy-dispersive x-ray spectroscopy (EDX). Electrochemical properties such as electrochemical activity, electrochemical active surface area (ECSA), and long-term stability of the Pd-W@Fullerene-C₆₀ catalyst for ethanol and methanol oxidation in the alkaline medium were explored by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). Results revealed that the proposed catalyst showed enlarged ECSA, tremendous electrocatalytic activity, high poison tolerance limit, good reproducibility, and enhanced long-term stability as compared to the monometallic catalyst and commercially available catalyst (Pt/C) towards ethanol and methanol oxidation reaction. This enhanced potentiality of the Pd-W@Fullerene-C₆₀ catalyst is due to the synergistic effect of W−Pd nanoparticles and excellent electron kinetic from fullerene support material. These findings strongly suggest the Pd-W@Fullerene-C₆₀ catalyst as potential anode material for the alcohol oxidation reaction.     

Formation of a Single-Crystal Aluminum-Based MOF Nanowire with Graphene Oxide Nanoscrolls as Structure-Directing Agents

An innovative strategy is proposed to synthesize single-crystal nanowires (NWs) of the Al³⁺ dicarboxylate MIL-69(Al) MOF by using graphene oxide nanoscrolls as structure-directing agents. MIL-69(Al) NWs with an average diameter of 70±20 nm and lengths up to 2 μm were found to preferentially grow along the [001] crystallographic direction. Advanced characterization methods (electron diffraction, TEM, STEM-HAADF, SEM, XPS) and molecular modeling revealed the mechanism of formation of MIL-69(Al) NWs involving size-confinement and templating effects. The formation of MIL-69(Al) seeds and the self-scroll of GO sheets followed by the anisotropic growth of MIL-69(Al) crystals are mediated by specific GO sheets/MOF interactions. This study delivers an unprecedented approach to control the design of 1D MOF nanostructures and superstructures.     

HBF4·OEt2 as a versatile reagent for the Hosomi-Sakurai allylation and Prins cyclization: one-pot synthesis of symmetrical 4-fluorotetrahydropyrans

The synthesis of symmetrical 2,6-disubstituted 4-fluorotetrahydropyran derivatives has been achieved using HBF₄·OEt₂ via a tandem allylation and Prins cyclization. This is a highly efficient and diastereoselective approach for the preparation of 4-fluorotetrahydropyrans in a single step. The use of readily available and easy to handle reagent HBF₄·OEt₂ makes this method simple, convenient and practical.     

The stereoselective total synthesis of (+)-garvensintriol

A simple and highly efficient stereoselective total synthesis of (+)-garvensintriol, isolated from the stem bark of Goniothalamus arvensis, is described using Sharpless kinetic resolution, MacMillan α-hydroxylation, and Horner-Wadsworth-Emmons olefination as the key steps.     

Production of Poly (3-Hydroxybutyric Acid) by <Emphasis Type="Italic">Ralstonia eutropha</Emphasis> in a Biocalorimeter and its Thermokinetic Studies

Bioplastic production from microbial sources is an emerging area which provides opportunities even to convert the wastes into bioplastics. Poly (3-hydroxybutyric acid), commonly called as PHB, is a bioplastic, which is stored as intracellular cytoplasmic inclusions in microorganisms. The objectives of this study are to calorimetrically monitor the PHB production and evaluate the thermokinetic data in a bioreaction calorimeter (BioRC1e). Thus, a well-known PHB-producing bacteria Ralstonia eutropha was selected for batch process in a bioreaction calorimeter. The metabolic heat generated was found to be correlated with the biomass, substrate consumption, oxygen uptake rate (OUR), carbon dioxide evolution rate (CER) and PHB production. The OUR pattern explained the oxidative metabolism of the strain R. eutropha. The heat yields due to biomass and glucose consumption during PHB production were found to be 12.56 and 13.56 kJ/g, respectively. The oxycalorific value obtained for the PHB production was 443.80 kJ/mol of O₂. The concentration of PHB obtained in BioRC1e was 4.33 g/L with a production rate of 0.09 g/L/h. The chemical structure of the extracted PHB by R. eutropha was confirmed using fourier transform infrared spectroscopy (FT-IR) and ¹H and ¹³C nuclear magnetic resonance (NMR) analysis.     

Utilization of Cheese Whey Using Synergistic Immobilization of β-Galactosidase and <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> Cells in Dual Matrices

Whey is a byproduct of the dairy industry, which has prospects of using as a source for production of various valuable compounds. The lactose present in whey is considered as an environmental pollutant and its utilization for enzyme and fuel production, may be effective for whey bioremediation. The dairy yeast Kluyveromyces marxianus have the ability to utilize lactose sharply as the major carbon source for the production of the enzyme. Five strains were tested for the production of the β-galactosidase using whey. The maximum β-galactosidase activity of 1.74 IU/mg dry weight was achieved in whey using K. marxianus MTCC 1389. The biocatalyst was further immobilized on chitosan macroparticles and exhibited excellent functional activity at 35 °C. Almost 89 % lactose hydrolysis was attained for concentrated whey (100 g/L) and retained 89 % catalytic activity after 15 cycles of reuse. Finally, β-galactosidase was immobilized on chitosan and Saccharomyces cerevisiae on calcium alginate, and both were used together for the production of ethanol from concentrated whey. Maximal ethanol titer of 28.9 g/L was achieved during fermentation at 35 °C. The conclusions generated by employing two different matrices will be beneficial for the future modeling using engineered S. cerevisiae in scale-up studies.     

Antihyperglucolipidaemic and anticarbonyl stress properties in green,yellow and red sweet bell peppers (Capsicum annuum L.)

Effect of aqueous methanol extract of different colour sweet bell peppers (Capsicum annuum L.) on parameters of diabesity and carbonyl stress was analysed in vitro. Yellow pepper displayed significantly (p < 0.001) higher intestinal α-glucosidase inhibitory activity than green and red pepper. Porcine pancreatic lipase inhibitory activity was significantly (p < 0.01) high in yellow and red pepper than in green pepper. Green and red pepper inhibited vesperlysine-type advanced glycation end products (AGEs) more potently than yellow pepper; however, pentosidine-type AGEs were similarly inhibited by all three peppers. Yellow and red pepper inhibited lipid peroxidation more potently (p < 0.01) than green pepper. Total polyphenol content and free radicals scavenging activities in yellow and red bell peppers were higher than in green pepper. Total flavonoid content was high in green pepper than that present in yellow and red peppers. Green pepper displayed presence of proanthocyanins; however, oligomeric anthocyanins were detected in yellow and red peppers.     

Facile extraction,processing and characterization of biorenewable sisal fibers for multifunctional applications

Synthetic fibers based materials have replaced most of the traditional metallic/ceramic materials for a number of applications owing to their enormous properties such as light weight, specific strength and modulus to name a few. Unfortunately, the traditional synthetic fibers are not desired from the health and environmental point of view. So, in this work, we have carried out the isolation, processing and characterization of cellulosic sisal fibers. These fibers were extracted for the first time by a simple and new unique mechanical extraction technique without affecting the quality of fibers. Subsequently these cellulosic sisal fibers were thoroughly characterized for their physicochemical, microstructure and mechanical properties. These fibers were then converted into fine textured sisal textile yarn made out of 3–6 sisal fibers in continuous operation and used for the preparation of new green materials. Different properties of fine textured sisal textile and the impact of sisal fine textile on the physical, microstructural, thermal and mechanical characteristics of the green materials were studied and discussed in detail.     

AlCl3 induced C-N bond formation followed by Pd/C-Cu mediated coupling-cyclization strategy: synthesis of pyrrolo[2,3-b]quinoxalines as anticancer agents

AlCl₃ facilitated C-N bond forming reaction between 2,3-dichloroquinoxaline and anilines affording a convenient method for the preparation of N-aryl substituted 3-chloroquinoxalin-2-amines. A related N-benzyl derivative, however, was prepared via a conventional method. These N-alkyl/aryl substituted 3-chloroquinoxalin-2-amines on coupling with terminal alkynes in toluene under Pd/C-Cu catalysis afforded a range of 1,2-disubstituted pyrrolo[2,3-b]quinoxalines within 3-5 h in good to excellent yields. Some of the compounds synthesized showed promising anti-proliferative properties when tested in vitro against two cancer cell lines. Docking studies indicated that these molecules interact well with human Akt in silico.     

Production and Purification of Pectinase from Bacillus subtilis 15A-B92 and Its Biotechnological Applications

Enzymes that degrade pectin are called pectinases. Pectinases of microbial origin are used in juice clarification as the process is cost-effective. This study screened a pectinase-producing bacterium isolated from soil and identified as Bacillus subtilis 15A B-92 based on the 16S rRNA molecular technique. The purified pectinase from the isolate showed 99.6 U/mg specific activity and 11.6-fold purity. The molecular weight of the purified bacterial pectinase was 14.41 ± 1 kD. Optimum pectinase activity was found at pH 4.5 and 50 °C, and the enzyme was 100% stable for 3.5 h in these conditions. No enzymatic inhibition or activation effect was seen with Fe²⁺, Ca²⁺, or Mg²⁺. However, a slight inhibition was seen with Cu²⁺, Mn²⁺, and Zn²⁺. Tween 20 and 80 slightly inhibited the pectinase, whereas iodoacetic acid (IAA), ethylenediaminetetraacetate (EDTA), urea, and sodium dodecyl sulfate (SDS) showed potent inhibition. The bacterial pectinase degraded citrus pectin (100%); however, it was inactive in the presence of galactose. With citrus pectin as the substrate, the Km and Vmax were calculated as 1.72 mg/mL and 1609 U/g, respectively. The high affinity of pectinase for its substrate makes the process cost-effective when utilized in food industries. The obtained pectinase was able to clarify orange and apple juices, justifying its application in the food industry.