Developing smart, environmentally friendly, and effective antibacterial surfaces is fundamental to contrast the diffusion of human infections and diseases for applications in the biomedical and food packaging sectors. To this purpose, here we combine aluminum-doped zinc oxide (AZO) and Ag to grow nanostructured composite coatings on bioplastic polylactide (PLA) substrates. The AZO layers are grown by RF magnetron sputtering, and then functionalized with Ag in atomic form by RF magnetron sputtering and in form of nanoparticles by supersonic cluster beam deposition. We compare the morphology, wettability, and antimicrobial performance of the nanostructured coatings obtained by the two methods. The different growth modes in the two techniques used for Ag functionalization are found to produce some differences in the surface morphology, which, however, do not induce significant differences in the wettability and antimicrobial response of the coatings. The antibacterial activity is investigated against Escherichia coli and Staphylococcus aureus as representatives of Gram-negative and Gram-positive bacteria, respectively. A preferential antimicrobial action of Ag on the first species and of AZO on the second one is evidenced. Through their combination, we obtain a hybrid composite coating taking advantage of the synergistic dual action of the two materials deposited, with a total bacterial suppression within few minutes for the first species and few hours for the second one, thus representing a valuable solution as a wide-spectrum bactericidal device.

This work aims to test the feasibility of a Fontinalis antipyretica devitalized moss clone to uptake and accumulate polycyclic aromatic hydrocarbons (PAHs) from surface waters. To assess the capability of the devitalized clone to accumulate PAHs, in the laboratory, moss was placed in water and spiked with increasing concentrations of 16 PAHs, and under field conditions, the moss was transplanted to 22 sites of Galicia (Spain) rivers. In general, PAH concentrations in water samples were lower than the maximum allowable concentrations from Directive 2013/39/EU, so the sampling sites did not show water PAH contamination. The exponential accumulation kinetic in the laboratory trial highlights a good capability of the devitalized moss clone to accumulate total PAHs. In field experiments, the hydrogeological conditions and the low emission sources caused low concentrations of PAHs in the water system and, consequently, in the transplants, although an enrichment can be observed for several PAHs. Overall, the devitalized clone of F. antipyretica can uptake and accumulate PAHs in water and may be useful in bioremediation strategies.

Soil microbial community plays a major role in removal of polycyclic aromatic hydrocarbons (PAHs) from soil, and bioremediation potentially offers an attractive and economic approach to the clean-up of polluted areas. To evaluate the contribution of different microbial groups in soil PAH degradation, enzymatic activity and phospholipid fatty acids (PLFAs) were analysed in a mesocosm trial in three different soils (two natural and one industrial) artificially contaminated with 3- and 5-rings PAHs. The Metabolic Activity Index (MAI) was applied to investigate the microbial community stability, in terms of resistance and resilience. Gram+ and Gram- bacteria were the predominant microbial groups in all soil types. In the first stage of incubation, fungi were predominant in the industrial soil, followed by mycorrhizae and actinomycetes, indicating their stimulation after PAH addition. In the two natural soils, several groups were predominant: actinomycetes in one, fungi and mycorrhizae in the other, indicating a different response of the two natural soils to PAH contamination. Regarding MAI calculated on the enzymatic activities, one natural soil showed a microbial community neither resistant nor resilient in respect to the other and to the industrial soil. Our results highlight that the microbial community changes its composition and then physiological functions according to the land use as a result of PAH addition.

Fresh-cut leafy vegetables are produced in Southern Italy in very intensive crop systems under tunnel greenhouses in which continuous cropping has triggered soil organic carbon (SOC) depletion and the risk of degradation of soil fertility. A two-year trial of soil organic amendment was carried out on a private farm producing baby-leaf crops on a very poor OC soil (<1%). Biowaste compost, two types of olive pomace composts and buffalo manure were compared to evaluate their ability to recover a positive SOC balance and sustain crop growth and yield. The effects on soil health and crop system were studied by measuring different aspects such as SOC stock change and SOC sequestration rate, soil microbial biomass and nine enzyme activities, yields of rocket and concentration of nitrates in leaves. Soil amendments were distributed once a year at doses of 15 and 30 Mg ha⁻¹ as fresh matter without integration of mineral fertilizers. In our study, the SOC stock improved in the amended soils in a range of 4–6 Mg ha⁻¹, except for dose 30 of buffalo manure, with the highest values where biowaste compost was applied. Our data showed an increase in biological parameters in all the amended soils with respect to Control. In soil amended with olive pomace, however, compost mineralization rates likely did not match crops’ nutrient needs so the yields of rocket were lower than with the biowaste compost and buffalo manure. Biowaste compost showed the best results as it balanced the best C conversion efficiency, the higher increment of SOC and yields of rocket.