Heterogeneously catalyzed lignin depolymerization

Biomass offers a unique resource for the sustainable production of bio-derived chemical and fuels as drop-in replacements for the current fossil fuel products. Lignin represents a major component of lignocellulosic biomass, but is particularly recalcitrant for valorization by existing chemical technologies due to its complex cross-linking polymeric network. Here, we highlight a range of catalytic approaches to lignin depolymerisation for the production of aromatic bio-oil and monomeric oxygenates

Clostridium difficile infection.

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota

Preparation, characterization and antibacterial applications of ZnAl-LDH with the diaminododecylphosphonic acid intercalation

International audienceLayered double hydroxides (LDHs) have been widely investigated in a wide range of applications in health, in the pharmaceutical industry and in the material of biotechnology industries. This material can be considered as a group of promising materials in the development of new health applications. The combination of phosphonic acid with LDHs material create a new hybrid material with new properties.In this work the synthesis of Zn/Al double layered hydroxides by chemical co-precipitation method (molar ration 2) and grafted with Diamino Dodecyl Phosphonic Acid (DDPA) via anion-exchange mechanism. The samples were characterized and confirmed by X-ray diffraction (XRD), and the presence of diamino dodecyl phosphonic acid (DDPA) was verified by Elemental analysis, BET analysis, and infrared spectroscopy. Both of the samples were found to be showing antibacterial activity. The zone diameters of Zn-Al-LDH were 40 mm and 25 mm for Escherichia coli(ATCC 25922) and Streptococcus (ATCC 25922)and 20 mm for bacillus (ATCC 25922) whereas the same for hybrid LDH (Zn-Al-DDPA) were43 mm , 32 mm and 25 mm for the same bacteria showing stronger antibacterial activity of the grafted material over the material itself. The experimental results confirm the application of Zn-Al-DDPA in the field of antibacterial activities and may offer a promising antibacterial elucidation to the society.doi: 10.38150/sajeb.11(5).p600-604429

Electrochemical behavior and electrocatalytic properties towards hydrogen peroxide, dioxygen and nitrate of the polyanions [(Ni(II)OH₂)₂(Fe(III))₂(X₂W₁₅O₅₆)₂]¹⁴¯ (X = P(V) or As(V)): A comparative study

In this study, the electrochemical behavior and the electrocatalytic properties towards the reduction of hydrogen peroxide, dioxygen and nitrate are compared for the two mixed sandwich-type complexes Ni₂Fe₂P₄ and Ni₂Fe₂As₄. In media of pH 3, Ni₂Fe₂P₄ displayed two waves corresponding to the reduction of the two Fe(III) centers within the complex followed by four W(VI) based-waves. Compared to Ni₂Fe₂P₄, Ni₂Fe₂As₄ displayed only one Fe-based wave and three W-waves. In other words, the two Fe(III) waves and the first two W(VI) waves observed for Ni₂Fe₂P₄ merge into one Fe-based wave and one W-wave in Ni₂Fe₂As₄. This is probably related to a slight difference in acidity between the two complexes. In other words, Ni₂Fe₂P₄ is slightly more basic than Ni₂Fe₂As₄. This difference in acidity is also reflected in the position of the potentials. Compared to Ni₂Fe₂P₄, the peak potentials of Ni₂Fe₂As₄ are slightly shifted towards positive values, and the shift is more pronounced for the W-based waves than for the Fe-waves. The remarkable stability of the two complexes (roughly from pH 0 to 7) permitted to evaluate their catalytic behavior towards H₂O₂, O₂ and NO₃. For the electrocatalytic reduction of H₂O₂, it is noticed that Ni₂Fe₂As₄ is more efficient than Ni₂Fe₂P₄. However, for O₂ and NO¯₃ it is observed that Ni₂Fe₂P₄ is more efficient than Ni₂Fe₂As₄.status: publishe