Cinzia Cristiani

This study aims to demonstrate the feasibility of the use of chestnut waste as a green and circular material for developing iron-based photocatalysts for non-steroidal anti-inflammatory drug (NSAID) photodegradation. Four Fe-based catalysts and two pristine biochars were obtained upon a pyrolysis process at 500 and 700 °C and fully characterised. Due to the applied synthesis, iron is present in the form of isotropic grains of magnetite (Fe₃O₄), quite homogeneously dispersed onto the biochar. The textural properties of all the materials are mainly determined by the pyrolytic temperature, which results in macroporous materials at 500 °C and microporous ones at 700 °C. Fe-based catalysts were tested in Diclofenac (DFC) photodegradation. DFC removal was the result of both adsorption and photocatalytic reactions. Despite the good yield in DFC removal (80–100%), the formation of degradation by-products can partially invalidate the good effectiveness of this approach. However, the encouraging results of this study represent a step forward for the possible development of waste-derived biochar-based catalysts for in-field application.

Background: Biochar has gained increasing attention for its potential benefits in improving animal health. Its physical and chemical properties depend on the starting biomass and production technology. This study investigates its functional properties versus bacteria. Methods: The morphology and physical properties of biochar from vine pruning were evaluated by SEM. The adsorption capacity for pathogenic E. coli F4+ and F18+ and probiotic microorganisms such as Lactobacillus sp. was assessed by plate count after contact with biochar. The growth activity on pathogenic and probiotic bacteria was tested after in vitro digestion. Results: Biochar from grapevine pruning did not maintain the original structure and showed both smooth and rough surfaces. The binding capacity varied across bacterial species. At concentrations of 20 mg/mL, up to 74% of E. coli adhered to the biochar surface, while the maximum adsorption rate of Lactobacillus sp. was around 38%. An inhibitory activity against E. coli (maximum reduction: 35%) and a growth-promoting effect for Lactobacillus sp. were observed (maximum promotion: 6%). Conclusions: These findings highlight the potential of biochar as a functional feed ingredient and that its functional properties are preserved after in vitro digestion.

Adsorption is one of the simplest and most cost-effective techniques for water decontamination. In this field, biochar has recently emerged as a promising alternative to traditional adsorbents, exhibiting a high surface area and affinity to metal ions, as well as often being waste-derived. Similarly, reduced graphene oxide (rGO) shows an excellent adsorption capacity. Having self-assembling properties, it has already been employed to obtain self-standing heavy-metal-adsorbing membranes. In this research, a novel self-standing membrane of biochar and rGO is presented. It was obtained through an eco-friendly method, consisting of the simple mechanical mixing of the two components, followed by vacuum filtration and mild drying. Vine pruning biochar (VBC) was employed in different rGO/biochar mass ratios, ranging from 1/1 to 1/9. The best compromise between membrane integrity and biochar content was achieved with a 4/6 proportion. This sample was also replicated using chestnut-shell-derived biochar. The composite rGO–biochar membranes were characterized through XRD, FTIR-ATR, TG-DTG, SEM-EDX, BET, ZP, particle dimension, and EPR analyses. Then, they were tested for metal ion adsorption with 10 mM Cu²⁺ and 100 mM Zn²⁺ aqueous solutions. The adsorption capacity of copper and zinc was found to be in the range of 1.51–4.03 mmol_Cu g⁻¹ and 18.16–21.99 mmol_Zn g⁻¹, respectively, at an acidic pH, room temperature, and contact time of 10 min. Interestingly, the composite rGO–biochar membranes exhibited a capture behavior between that of pure rGO and VBC.

This work presents a study of the redox properties of CeO₂ particles with (FeCeHS) and without (CeHS) Fe₂O₃ impregnation, as possible innovative catalysts for oxidation and combustion reactions as well as CO₂ activation. The topic, therefore, is part of a broader analysis of environmental catalysis, which aims to reduce the emissions of polluting substances and improve the exploitation of energy resources, with consequent progress in the eco-friendly field. Different laboratory techniques (Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Ultraviolet–Visible (UV-Vis), and Fourier Transform–Infrared (FT-IR) spectroscopies) point out that iron oxide is deposited on the surface of ceria, which maintains its lattice structure, although the particle morphology is slightly changed. Methanol and ethanol adsorption and conversion were evaluated on these catalysts by Temperature Programmed Surface Reaction (TPSR) and by in situ FT-IR spectroscopy of the probe redox properties, evidencing the formation of surface oxidized intermediates and combustion products. The FeCeHS catalyst demonstrates, in our reaction conditions, a good combustion activity in total oxidation of oxygenated molecules, hindering the formation of formaldehyde from methanol and reducing the quantity of CO produced by the partial oxidation reaction. A cooperative effect is suggested by the mixture of these two metals in the oxidation process.

Biochar is potentially a functional ingredient in animal nutrition that offers health benefits such as detoxification, while also promoting environmental sustainability through carbon sequestration, emission reduction, and its circular production. However, the heterogeneity of commercially available biochar products requires a detailed assessment of their functional properties for applications in animal feed. This study evaluates chestnut biochar from morphological, chemical, and metabolomic perspectives and assesses its functional properties. Metabolomic analysis of a water extract using QTOF HPLC-MS/MS confirmed the presence of bioactive compounds, such as hydroxybenzoic and succinic acids, highlighting its potential as a functional feed ingredient. The chestnut biochar inhibited the growth of the pathogenic E. coli strains F18+ and F4+, with maximum inhibition rates of 15.8% and 28.6%, respectively, after three hours of incubation. The downregulation of genes associated with quorum sensing (MotA, FliA, FtsE, and HflX, involved in biofilm formation and cellular division) suggests that biochar interferes with several aspects of the pathogenic process. Importantly, biochar was not found to adversely affect beneficial probiotic bacteria, such as Lactiplantibacillus plantarum and Limosilactobacillus reuteri. These findings support the potential of chestnut biochar as a versatile ingredient for sustainable animal nutrition, thus promoting animal welfare while offering environmental benefits.

Biochar has gained interest as a feed ingredient in livestock nutrition due to its functional properties, circularity, potential to reduce environmental impact, and alignment with sustainable agro-zootechnical practices. The in vivo effects of biochar are closely tied to its physical characteristics, which vary depending on the biomass used as feedstock and the production process. This variability can result in heterogeneity among biochar types used in animal nutrition, leading to inconsistent outcomes. The aim of this study was to characterize the metabolomic and functional properties of an aqueous biochar extract from vine pruning waste, in order to predict its potential in vivo effects as a functional feed ingredient. A metabolomic analysis of the biochar extracts was conducted using quadrupole time-f-light (QQTOF) high-performance liquid chromatography tandem mass spectrometry (HPLC MS/MS). Antimicrobial activity against E. coli F18+ and E. coli F4+ was assessed using standard growth inhibition assays, while quorum sensing in E. coli exposed to biochar extracts was evaluated using real-time PCR. Prebiotic activity was assessed by exposing selected Lactobacillus strains to the biochar extract, monitoring growth patterns to determine species-specific responses. The metabolomic profile revealed several distinct molecular classes, including multiple peaks for phenolic compounds. The extract significantly inhibited the growth of both E. coli pathotypes, reducing growth by 29% and 16% for the F4+ and F18+, respectively (p < 0.001). The relative expression of the genes involved in quorum sensing (MotA, FliA for biofilm formation, and FtsE, HflX for cell division) indicated that the observed inhibitory effects likely resulted from interference with flagellar synthesis, motility, and reduced cell division. The biochar extract also showed species-specific prebiotic potential. In conclusion, biochar derived from vine pruning waste represents a valuable feed ingredient with functional properties that may help to reduce antibiotic use in livestock production.

Heavy metals, such as Pb(II), Cr(III), and Cd(II), are frequently discharged into the environment, resulting in a threat for the health of living organisms. Microalgae represent an ecological method for the removal of these pollutants. The capture capability of active and dried Chlamydomonas reinhardtii towards both mono-ionic and multi-ionic solutions is evaluated to study the bioremediation in low-polluted wastewaters. Several characterization techniques have been performed to study morphology, composition, and the interaction between the metals and the microalgal functional groups of the wall. The effect of the operating conditions, such as contact time and pH, is assessed; an increased contact time of 4 days did not influence the adsorption yields of Pb and Cr, but it had a negative effect on Cd adsorption, while the impact of pH was mainly affecting the chemical speciation, rather than the adsorption capability. The microalga showed a larger affinity for Pb and Cd, respectively, 80 and 76% (w/w) of adsorption, while only the 65% (w/w) of the total Cr was adsorbed, suggesting a preferential biosorption.

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules’ in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo^®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mg_LY/g_AD (LY(32)-AD) was obtained, with fixing pH in the range 7.5–8, initial LY content at 37.5 mg_LY/g_AD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier’s surface, where the LY–carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%.

A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75^®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is a simple and effective way for preparing hybrid materials characterized by LY loadings up to 37 mg_LY/g_carrier. By operating at pH 4.3, initial LY content of 37.5 mg_LY/g_carrier, and reaction time of 90 min, hybrid materials with LY loadings of 37, 35, and 12 mg_LY/g_carrier for LY-SP, LY-BN, and LY-PH, respectively were obtained. The LY initial concentration and pH, as well as the physico-chemical properties of the carries were found to be the parameters that govern the synthesis of the materials. The driving force for an effective LY adsorption and interaction is the combined Zero Point Charge (ZPC) of the carriers, always negative (in the range between −4 and −170 mV) and the positive ZPC of LY, as well as the carrier morphology, characterized by mesoporosity (pore dimensions in the range of 5–12 nm). However, it is the interaction of charges of opposite sign that mainly affects LY loadings and bond strength. Based on SEM-EDX analysis, LY molecules are quite homogeneously spread onto the carriers’ surface. TG-DTG analyses showed that the LY–carrier interaction in the hybrid materials is stronger than that in a simple mechanical mixture of the components. Specifically, in the hybrid materials, the phenomenon at 300 °C, associated to LY decomposition, is broadened and slightly shifted towards higher temperatures (320–350 °C), whereas in a mechanical mixture of the same composition, it occurs at temperatures closer to those of free LY, as if there were no or very weak interactions. At pH 3, a very little LY release, 0.03 and 0.01 mg_LY/g_carrier, was found for LY-BN and LY-PH, respectively. The latter became larger at pH 7, 0.06 mg_LY/g_carrier for both BN and PH carriers, suggesting that BN and PH are better modulators of LY release. The paper provides insights for the study and the development of new optimized feed formulations for the targeted delivery of natural compounds with antimicrobial activity, alternatives to antibiotics, and vaccinal antigens.