This study exposed a microalgal consortium formed by Auxenochlorella protothecoides, Tetradesmus obliquus, and Chlamydomonas reinhardtii to six mixed wastewater media containing different proportions of primary (P) or secondary (S) effluents diluted in centrate (C). Algae could grow at centrate concentrations up to 50 %, showing no significant differences between effluents. After acclimation, microalgae cultivated in 50%P-50%C and 50%S-50%C grew at a rate similar to that of control cultures (0.59-0.66 d^-1). These results suggest that the consortium acclimated to both sewage streams by modulating the proportion of the species and their metabolism. Acclimation also altered the photosynthetic activity of wastewater-grown samples compared to the control, probably due to partial photoinhibition, changes in consortium composition, and changes in metabolic activity. No major differences were observed between the two streams with respect to biochemical composition, biomass yield, or bioremediation capacity of the cultivated algae but algae grown in the secondary effluent showed qualitatively higher exopolysaccharides (EPS) production than algae grown in primary. Regarding wastewater remediation, microalgae grown in both WW media showed proficient nutrient removal efficiencies (close to 100 %); however, the final pH value (close to 11) would be controversial if the system were upscaled as it is over the legal limit and would cause phosphorus precipitation, so that CO₂ addition would be required. The theoretical scale-up of the microalgae system could achieve water treatment costs of 0.109 €·m^-3, which was significantly lower than the costs of typical activated sludge systems.

Digestate is a complex by-product of anaerobic digestion and its composition depends on the digestor inputs. It can be exploited as a sustainable source of nutrients for microalgae cultivation but its unbalanced composition and toxic elements make the use challenging. Screening algae in a simplified synthetic digestate which mimics the main nutrient constraints of a real digestate is proposed as a reproducible and effective method to select suitable species for real digestate valorisation and remediation. Growth performance, nutrient removal and biomass composition of eight microalgae exposed to high amounts of NH₄⁺, PO₄^- and organic-C were assessed. Using a score matrix, A. protothecoides, T. obliquus, C. reinhardtii, and E. gracilis were identified as the most promising species. Thus, three strategies were applied to improve outcomes: i) establishment of an algal consortium to improve biomass production, ii) K⁺ addition to the medium to promote K⁺ uptake over NH₄⁺ and to reduce potential NH₄⁺ toxicity, iii) P starvation as pretreatment for enhanced P removal by luxury uptake. The consortium was able to implement a short-term response displaying higher biomass production than single species (3.77 and 1.03-1.89 mg mL^-1 respectively) in synthetic digestate while maintaining similar nutrient remediation, furthermore, its growth rate was 1.6 times higher than in the control condition. However, the strategies aiming to reduce NH₄⁺ toxicity and higher P removal were not successful except for single cases. The proposed algal screening and the resulting designed consortium were respectively a reliable method and a powerful tool towards sustainable real digestate remediation.

Due to the increasing production of wastewater from human activities, the use of algal consortia for phytoremediation has become well‐established over the past decade. Understanding how interspecific interactions and cultivation modes (monocultures vs. polyculture) influence algal growth and behaviour is a cutting‐edge topic in both fundamental and applied science. Ammonium‐rich growth media were used to challenge the monocultures of Auxenochlorella protothecoides, Chlamydomonas reinhardtii and Tetradesmus obliquus, as well as their polyculture; NO₃⁻ was also used as the sole nitrogen chemical form in control cultures. The study primarily compared the growth, carbon and nitrogen metabolisms, and protein content of the green microalgae monocultures to those of their consortium. Overall, the cultivation mode significantly affected all the measured parameters. Notably, at 50 mM NH₄⁺, the assimilation rates of carbon and nitrogen were at least twice as high as those in the monoculture counterparts, and the protein content was three times more abundant.Additionally, the consortium's response to NH₄⁺ toxicity was investigated by observing a linear relationship between the indicator of tolerance to NH₄⁺ nutrition and the N isotopic signature. The study highlighted a high degree of acclimation through metabolic flexibility and diversity, as well as species abundance plasticity in the consortium, resulting in a functional resilience that would otherwise have been unattainable by the respective monocultures.

Silicon is one of the most abundant chemical elements in the universe. On Earth, it forms sediments, minerals, and rocks. In the ocean, silicon is found in a dissolved form that can be used by many organisms to grow. You probably know that humans use calcium to build their skeletons, but did you know that there are creatures capable of forming skeletons out of silicon? Organisms capable of capturing dissolved silicon from the environment and transforming it into glassy skeletons are called silicifiers. Silicifiers use a unique process called biosilicification to create their skeletons. In the marine ecosystem, silicifiers come in a surprising variety of shapes and sizes, and they include, among others, diatoms, rhizarians, and sponges. These three groups, so diverse and yet so similar, are essential to the health of the oceans.

This report presents the activities and outcomes of an educational project aimed at promoting sustainable food awareness among high-school students in Italy through the active contributions from young researchers, profit partners and school educators. The project involved two final-year classes—one from a scientific lyceum and one from a technical chemistry institute—and integrated theoretical lessons, laboratory activities, and experiential learning focused on planetary boundaries, sustainable diets, and alternative proteins such as from algae and insects. To assess the impact of the project, pre- and post-intervention questionnaires were administered and are here discussed. The intervention significantly enhanced the students’ cognitive and affective engagement both during the sessions and in the immediate aftermath, as evidenced by elevated levels of satisfaction and retention of key concepts. Overall, the project fostered great environmental awareness and openness to sustainable food choices, demonstrating the potential of targeted hands-on educational programs to influence both attitudes and behaviours in younger generations of western high-income countries. The project serves as a replicable model of a transdisciplinary approach for integrating Education for Sustainable Development (ESD) and education for Planetary Health into secondary school curricula.