On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites in solid acid catalysed esterification pretreatment of bio-oil

A family of faujasite (FAU) zeolites with different Si:Al ratio, and/or hierarchical porosity introduced via post-synthetic alkaline desilication treatment, have been evaluated as solid acid catalysts for esterification pretreatments of pyrolysis bio-oil components. Acetic acid esterification with aliphatic and aromatic alcohols including methanol, anisyl alcohol, benzyl alcohol, p-cresol and n-butanol was first selected as a model reaction to identify the optimum zeolite properties. Materials were fully characterised using N2 porosimetry, ICP, XRD, XPS, FT-IR, pyridine adsorption, NH3 TPD, In-situ ATR and inverse gas chromatography (IGC). IGC demonstrates that the surface polarity and hence hydrophobicity of FAU decreases with increased Si:Al ratio. Despite possessing a higher acid site loading and acetic acid adsorption capacity, high Al-content FAU possess weaker acidity than more siliceous catalysts. Esterification activity increases with acid strength and decreasing surface polarity following the order FAU30>FAU6>FAU2.6. The introduction of mesoporosity through synthesis of a hierarchical HFAU30 material further enhances esterification activity through improved acid site accessibility and hydrophobicity. Methanol was the most reactive alcohol for esterification, and evaluated with HFAU30 for the pretreatment of a real pyrolysis bio-oil, reducing the acid content by 76% under mild conditions

A recombinant conjugated pneumococcal vaccine that protects against murine infections with a similar efficacy to Prevnar-13

Pneumococcal vaccines: evaluation of a multivalent pneumococcal glycoconjugate vaccine The current pneumococcal conjugate vaccine induces protective immunity to infection, but this protection is limited to the dominant disease-causing strains included in the preparation. Emerging strains not included in the vaccine are not covered, which limits the vaccine’s protective effect in areas associated with alternative pneumococcal strains. Here Jeremy Brown, Brendan Wren and colleagues have optimised and applied Protein Glycan Coupling Technology to produce recombinant pneumococcal polysaccharide/protein glycoconjugates and evaluated these in a murine model of infection. Glycoconjugate vaccination resulted in antibody production specific to both capsule and the carrier proteins, which resulted in protection in murine models of meningitis and septicaemia equivalent to that of currently used vaccination strategies. This animal study highlights the potential of glycoconjugate vaccine approaches in the context of pneumococcal mediated disease