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The ability of Methylobacterium extorquensto grow on methanol as the sole carbon and energy source has been the object of intense research activity. Unquestionably, the bacterial cell envelope serves as a defensive barrier against such an environmental stressor, with a decisive role played by the membrane lipidome, which is crucial for stress resistance. However, the chemistry and the function of the main constituent of the M. extorquensouter membrane, the lipopolysaccharide (LPS), is still undefined. Here, we show that M. extorquensproduces a rough-type LPS with an uncommon, non-phosphorylated, and extensively O-methylated core oligosaccharide, densely substituted with negatively charged residues in the inner region, including novel monosaccharide derivatives such as O-methylated Kdo/Ko units. Lipid A is composed of a non-phosphorylated trisaccharide backbone with a distinctive, low acylation pattern; indeed, the sugar skeleton was decorated with three acyl moieties and a secondary very long chain fatty acid, in turn substituted by a 3-O-acetyl-butyrate residue. Spectroscopic, conformational, and biophysical analyses on M. extorquensLPS highlighted how structural and tridimensional features impact the molecular organization of the outer membrane. Furthermore, these chemical features also impacted and improved membrane resistance in the presence of methanol, thus regulating membrane ordering and dynamics.

The evolution of methicillin-resistant Staphylococcus aureus(MRSA) has required the development of new antimicrobial agents and new approaches to prevent and overcome drug resistance. AntiMicrobial Peptides (AMPs) represent promising alternatives due to their rapid bactericidal activity and their broad-spectrum of action against a wide range of microorganisms. The amphibian Temporins constitute a well-known family of AMPs with high antibacterial properties against both Gram-positive and Gram-negative bacteria. In this paper, we evaluated the in vivo effect of Temp-L on S. aureusperforming morphological studies using Transmission Electron Microscopy (TEM) that revealed the occurrence of protrusions from the cell surface. The formation of vesicle-like structure was confirmed by Dynamic Light Scattering (DLS). The global effect of Temp-L on Staphylococcus aureus(S. aureus) was deeply investigated by differential proteomics leading to the identification of up-regulated proteins involved in the synthesis of the cell membrane and fatty acids, and down-regulated virulence factors. GC-MS analysis suggested a possible protective response mechanism implemented by the bacterium after treatment with Temp-L, as the synthesis of fatty acids was increased. Adhesion and invasion assays on eukaryotic cells confirmed a reduced virulence of S. aureusfollowing treatment with Temp-L. These results suggested the targeting of virulence factors as novel strategy to replace traditional antimicrobial agents that can be used to treat infections, especially infections caused by the resistant pathogen S. aureus.

The use of technologies based on soft polymer particles represents an effective way to deliver target molecules with a specific function. To design a well-performing delivery system, it is fundamental to rationalize both the aggregation and the structural properties of such particles. In this study, we present the kinetic and structural characterization over time of poly(vinyl alcohol) (PVA) microgels obtained through a salting-out process in the presence of NaCl. We have analyzed how both the polymer and salt concentrations affect the aggregation process. The aggregation rate as well as the morphology and physico-chemical parameters, such as mass and chain density of the microgels, have been determined through static and dynamic light scattering and discussed in the framework of the diffusion-limited and reaction-limited colloid aggregation. Insights into the polymer chain arrangements and their dynamics have been gained by means of small-angle neutron scattering and neutron spin-echo measurements. As a result, it was found that NaCl induces a liquid phase separation in solution with the formation of spherical PVA microaggregates, which grow under a reaction-limited aggregation mechanism. The particles increase their size and compactness over time. Within the aggregate, the polymer chains are locally organized to form randomly oriented lamellae with a thickness of about 60 Å. The internal dynamics is a complex mixture of diffusion, Zimm dynamics, and possibly effects from crowding with the transition to a Rouse-like behavior. The microparticle preparation based on the salting-out process constitutes a novelty, if compared to the methods already existing and based on the use of chemical cross-linkers, and is a cheap and easy protocol that allows tuning both particle size and density by varying the salt concentration.

The waste-to-wealth strategy is encouraging the design of a plethora of new value-added materials, by exploiting the chemical and biological richness of biowastes. Humic Acids (HA) are mostly intriguing because of their amphiphilic supramolecular associations which are responsible for several assets, such as adsorption ability towards small molecules, metal ion chelation, redox behavior, and antibacterial activity. The molecular combination of HA with semiconductor nanoparticles represents a valuable strategy to obtain nanostructured hybrid materials and interfaces with advanced features. Concurrently, it permits to overcome intrinsic limits of such organic fraction, including poor stability, fast conformational dynamics, or rapid reactivity in aqueous media. Herein, hybrid HA/ZnO nanoparticles are synthetized through a bottom-up strategy, exerting an improved pro-oxidant behavior by generating Reactive Oxygen Species, even without light irradiation, favoring an enhanced photocatalytic and antimicrobial activity against different bacterial pathogens. Several techniques, including SEM/TEM, DLS, ζ-potential, XRD, FTIR, TGA/DSC, EPR and DRUV, allows to define the structure-property-function relationships, thus highlighting the crucial role of a fine conjugation amongst the metal oxide precursor and bioderived fraction to drive the pro-oxidant activity. This study provides strategic guidelines to easily produce low-cost organo-inorganic nanomaterials with redox and biocide properties, aimed at coping environmental and health issues.

β-Glucosidase (BG) catalyzes the hydrolysis of cellobiose to glucose, a substrate for fermentation to produce the carbon-neutral fuel bioethanol. Enzyme thermal stability and reusability can be improved through immobilization onto insoluble supports. Moreover, nanoscaled matrixes allow for preserving high reaction rates. In this work, BG was physically immobilized onto wrinkled SiO2nanoparticles (WSNs). The adsorption procedure was tuned by varying the BG:WSNs weight ratio to achieve the maximum controllability and maximize the yield of immobilization, while different times of immobilization were monitored. Results show that a BG:WSNs ratio equal to 1:6 wt/wt provides for the highest colloidal stability, whereas an immobilization time of 24 h results in the highest enzyme loading (135 mg/g of support) corresponding to 80% yield of immobilization. An enzyme corona is formed in 2 h, which gradually disappears as the protein diffuses within the pores. The adsorption into the silica structure causes little change in the protein secondary structure. Furthermore, supported enzyme exhibits a remarkable gain in thermal stability, retaining complete folding up to 90 °C. Catalytic tests assessed that immobilized BG achieves 100% cellobiose conversion. The improved adsorption protocol provides simultaneously high glucose production, enhanced yield of immobilization, and good reusability, resulting in considerable reduction of enzyme waste in the immobilization stage.

Three different deep eutectic solvent (DES)-based extraction procedures were rationally designed and optimized for the recovery of antioxidants from chestnut wood fiber (CWF), a clean and largely available solid waste of the tannin industry. First, a mild protocol was developed using a choline chloride (ChCl)/tartaric acid DES at 50 °C, for 90 min. Ellagic acid (EA) was identified as the only low molecular weight phenolic component of the extract. In other experiments, harsher conditions were explored involving treatment of CWF with ChCl-based DESs at 120 °C for 8 h, which afforded a solid sample characterized by high phenolic content (up to 1.0 mg of gallic acid equivalents/mg of sample) and antioxidant properties (EC50<0.025 mg/mL in the 2,2-diphenyl-1-picrylhydrazyl assay), and containing guaiacyl-syringyl lignin along with EA. Based on these results, a sequential two-step DES-based treatment of CWF was eventually designed, allowing to selectively obtain both an EA-enriched and an EA-free, lignin-enriched sample, with an overall 50% w/w of the starting CWF dissolved. In particular, a 2.3% w/w yield of EA was achieved, which is significantly higher than those reported in the case of DES-based processing of other agricultural wastes. The proposed tunable, straightforward, and eco-friendly approach may allow to fully exploit CWF as a green, cheap, and easily accessible source of high-value products.

Ibuprofen is one the most used non-steroidal anti-inflammatory drug, which is considered an emerging pollutant that may contaminate surface and underground water. Photodegradation using nanomaterials is one of the most sustainable and cheap technologies that can be used in water purification. In this study, the photodegradation efficiency of in-house prepared ceria (CeO2) nanostructured materials towards ibuprofen was assessed under UV irradiation. CeO2nanoparticles (NPs) were prepared through wet-chemical synthesis and characterized by several techniques. The photodegradation activity of the synthesized CeO2-NPs was compared to the commercial Aeroxide TiO2-P25. Small crystalline CeO2-NPs were obtained with about 15 nm particle size, band-gap of 3.1 eV with irregular morphology. The surface area of CeO2-NPs was estimated to be 76 ± 5 m2/g. Dynamic light scattering analysis revealed that these nanoparticles have a strong tendency to self-aggregate and to form clusters in aqueous suspension. The results showed a slightly better performance of Aeroxide TiO2-P25 compared to CeO2-NPs. On the other hand, five reusability tests confirmed the stability of CeO2-NPs in the reaction conditions, without any significant effect on their photodegradation activity. The goodness of the kinetic modeling of the experimental data was proven through the estimated kinetic parameters, together with the statistical information. The temperature effect confirmed that the higher the temperature, the greater the dissociation rate. Thus, there is a direct relationship between temperature, reaction rate, and the activation energy for each reaction. Furthermore, the thermodynamic parameters, namely: changes in Gibbs free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) have been reported revealing the efficient photodegradation performance of CeO2-NPs.