The anchoring and mooring of boats mechanically damage Posidonia oceanica plants; however, no information is available on the effect of this kind of damage on the plant holobiont, i.e., on the associated bacterial and fungal communities. Indeed, bacterial communities are known to change under different plant stress conditions but the dynamics of seagrass-associated fungi remain largely unexplored. We used DNA metabarcoding to profile the bacterial and fungal colonizers of two nearby P. oceanica patches in the Villefranche-sur-Mer bay (France) differing by the amount of exposure to mechanical stress due to boat transit and anchoring. Bacterial communities showed a significant reduction in diversity with an increase in Vibrio sp. in the rhizome and root samples from the impacted site, where the accumulation of dead organic material favors opportunistic heterotrophs. Conversely, fungal communities showed increased diversity in the leaf samples from the impacted site, where a reduction in the dominant P. oceanica host-specific mutualistic endosymbiont, Posidoniomyces atricolor, was found. This change was probably due to the opening up of new colonizable niches for several fungal species. Although this study represents a preliminary assessment of the effect of mechanical stresses on P. oceanica-associated microbial communities, it further supports their putative use as a seagrass descriptor.

In the framework of regenerative circular economy and Sustainable Development Goals #6, water demand and wastewater production are a crucial environmental issue. To cope with this, a system called Zero Mile has been conceived to reuse/upcycle the dishwasher wastewater in both fertilisation of a vertical garden (for home plant production at zero mile) and the subsequent dishwasher rinsing cycle. The core of the Zero Mile system is a biofilter constituted by an ad hoc engineered microbial consortium, based on the mutualistic relationship between autotrophic and heterotrophic microbial partners, that makes the biodegradative process sustainable over time. Two semi-batch tests were performed to evaluate the capability and the efficiency of the microbial consortium to operate in conditions mimicking the Zero Mile system: consortia were challenged in two dishwasher wastewater volumes (50 and 500 mL), with a replenishing rate of 4 days for ¼ of the dishwasher wastewater volume. The results of these tests showed that the consortium thrives well in dishwasher wastewater over time and can survive with the volume and rates of replenishments. Next Generation Sequencing showed that the microbial consortium maintains a stable taxonomic composition, and chemical analyses demonstrated a very high bioremediation efficiency (total nitrogen and phosphorus removal). Aiming to contribute to the circular economy approach, the consortium ‘treated’ dishwasher wastewater was useful for plant fertilisation, as demonstrated by pigment content and quality indices (total phenols and flavonoids, soluble solids) measured in the lettuce plants grown in the Zero Mile demonstrator and watered with consortium reclaimed dishwasher wastewater.

Wastewaters from household appliances, such as dishwashers and washing machines, are an untapped resource of recoverable water and/or nutrients. The Zero Mile system has been developed to reuse/upcycle dishwasher wastewaters through bioremediation activity carried out by an ad hoc engineered phototrophic/heterotrophic microbial consortium. The choice of both suitable microorganisms for engineering consortia and detailed knowledge on their structure, behaviour and interaction are essential to optimising consortium culture conditions and drive the biofilter container design (structure and topology). To these aims, the effect of abiotic conditions (i.e., irradiance, pH and organic load) on the microbial consortium growth and its capability to survive and thrive in different dishwasher wastewater dilutions have been evaluated. At the same time, the crucial interplay between biological and design research has allowed us to define the characteristics of the biofilter container and plan its development for the industrial application of the Zero Mile system, bringing sustainability benefits as it moves household wastewater from a traditional linear model to a more sustainable, circular approach.

Ancient books and documents constitute an important cultural heritage, which are composed by different supports, such as cardboard, parchment and paper. Due to their composition (animal- and plant-based matrices), they allow bacteria and fungi to thrive, causing the phenomenon of biodeterioration, an ecological succession in parchment. Four ancient books called “Compositionum” from the Apostolic Vatican Archive, made of the same materials, exposed to weather-beating conditions and showing different degrees of deterioration, were analysed by a multidisciplinary approach: DNA metabarcoding using NGS, Light Transmission Analysis and Raman and FTIR spectroscopy. The results highlighted how the biodeteriogen community composition changed from the least to the most damaged, without evidence of significant microbial transfer across the three matrices. The results allow confirmation of the ecological succession as biodeterioration process, including cardboard and paper, in addition to in parchment. These results give important insight for the conservation and restoration practices of all matrices.