Superfood potential of Chlorella vulgaris: productivity and antioxidant boost under simulated moon and microgravity conditions Giacomo Fais, Filippo Ghiani, Debora Dessì, Mattia Casula, Giovanni Perra, Eleonora Torchia, Nicola Lai, Giacomo Cao, Alessandro Concas Npj Microgravity, 2026 As space missions extend to the Moon and beyond, Bioregenerative Life Support Systems (BLSS) are vital for food, oxygen, and resource recycling in closed habitats. We examined the physiological, biochemical, and lipidomic responses of Chlorella vulgaris (CCALA 269) grown under simulated Earth gravity (1 g), Moon gravity (0.17 g), and microgravity (μg) using a 3D clinostat. Reduced gravity was associated with higher biomass, photosynthetic pigments, and antioxidant capacity. Cultures under lunar and microgravity showed up to 170% more chlorophyll and carotenoids, and 160% more polyphenols and antioxidant activity. Lipidomics revealed membrane remodeling, with higher galactolipids and triacylglycerols, suggesting adaptations to preserve membrane function and energy reserves. These responses indicate substantial physiological plasticity in C. vulgaris , suggesting its potential relevance for BLSS as a source of nutrient-rich biomass, oxygen, and antioxidants. Our results suggest its potential for space food and life support, and the need for further research under real partial gravity conditions.
Mixotrophic Cultivation of Limnospira (Spirulina) platensis Using Early-Stage Fig Processing Wastewater: Effects on Biomass Composition, Antioxidants and Phycocyanin Luca Franzoso, Luca Usai, Riccardo Allodi, Giacomo Fais, Deborah Dessì, Robinson Soto-Ramirez, Bartolomeo Cosenza, Abderrahim Damergi, Giovanni Antonio Lutzu, Alessandro Concas Marine Drugs, 2026 The valorization of agro-industrial waste streams represents a promising strategy for reducing production costs in microalgae biotechnology while promoting circular economy approaches. In this study, wastewater derived from fig jam processing was evaluated as an organic carbon source for mixotrophic cultivation of Limnospira (Spirulina) platensis. Cultures were grown under four conditions: a control medium and three concentrations of fig wastewater (FW) at 0.75%, 1.5%, and 3% (v v−1). The wastewater used in this study originates specifically from the washing and cleaning stages of dried fig processing, representing an early processing stream characterized by relatively high soluble sugar content and low thermal or chemical alteration. Biomass biochemical composition and bioactive compound production were investigated, including carbohydrates, proteins, lipids, photosynthetic pigments, polyphenols, antioxidant activity, and phycocyanin extraction yield and purity. The results showed that fig wastewater supplementation significantly influenced the metabolic profile of L. platensis. The highest protein content was obtained at 0.75% FW (44.90 ± 1.93 g 100 g−1 DW), whereas lipid accumulation increased with FW concentration, reaching 9.45 ± 2.30 g 100 g−1 DW at 3% FW. Antioxidant activity peaked at 1.5% FW (4.33 ± 0.43 μmol Trolox mg−1 DW), suggesting stimulation of oxidative stress response pathways under moderate organic supplementation. Pigment production showed different responses, with relatively stable chlorophyll and carotenoid contents but decreasing phycocyanin levels at higher FW concentrations. Phycocyanin yield decreased from 9.82 ± 1.00 g 100 g−1 DW in the control to 5.80 ± 0.22 g 100 g−1 DW at 3% FW, while purity values were highest at the highest FW concentration. These findings demonstrate that fig processing wastewater can be effectively used as an alternative organic substrate for mixotrophic Spirulina cultivation, enabling simultaneous wastewater valorization and production of biomass rich in proteins and bioactive compounds.
Green-Synthesized Ag/Zn Nanocomposites from Chlorella vulgaris Polar Extract: Sustainable Photocatalytic Water Remediation and Kinetic Modeling Federico Zedda, Federico Atzori, Silvia Casu, Agnieszka Sidorowicz, Giacomo Fais, Francesco Desogus, Roberta Licheri, Stefania Porcu, Giacomo Cao, Giovanni Antonio Lutzu, Alessandro Concas Sustainability Switzerland, 2026 The growing demand for sustainable water treatment technologies requires photocatalysts that combine low environmental impact, energy efficiency, and mechanistic robustness. In this work, Ag/Zn nanocomposites were green-synthesized using Chlorella vulgaris polar extract as a bio-mediated reducing and stabilizing agent, eliminating hazardous reagents and high-energy processing steps. Structural characterization (XRD, FTIR, SEM, UV–Vis) confirmed the coexistence of crystalline wurtzite ZnO with metallic Ag and Ag2O phases. Photocatalytic activity was evaluated through Congo Red degradation under a sequential dark–light protocol, enabling clear separation of adsorption and photoactivated pathways. During the 60 min dark stage, removal remained limited (~9–11%), consistent with adsorption–desorption equilibration. Upon UV irradiation, a distinct kinetic transition occurred, leading to final removal efficiencies of 44–49% after 180 min. Notably, performance remained stable across the investigated photon flux range, indicating operation beyond a strictly photon-limited regime and highlighting an intrinsically energy-resilient catalytic response. A mechanistic kinetic model integrating reversible adsorption with light-dependent degradation accurately reproduced all experimental profiles (NRMSE=3.14%) and successfully predicted an independent dark-control experiment without additional fitting. By coupling green synthesis with quantitative kinetic validation, this study proposes a sustainability-oriented framework for designing photocatalysts that align low-impact fabrication with energy-conscious water remediation.
Influence of a low atmospheric pressure on the growth and lipid composition of Chlorella vulgaris Mattia Casula, Paola Scano, Giacomo Fais, Pierluigi Caboni, Marcus Elvert, Alessandro Concas, Giacomo Cao, Cyprien Verseux Algal Research, 2026 Within crewed missions to Mars, microalgae could be used for the production of essential consumables. Their cultivation there could be less resource-intensive if the pressure inside bioreactors was reduced. However, whether this would decrease their growth is unclear; and how the composition of their lipidome would change (for instance, to compensate for the tendency of low pressure to increase membrane fluidity) is unknown. Here we demonstrate that the growth of Chlorella vulgaris is unaffected by a reduction in total pressure from 1000 hPa (ca. Earth at sea level) to 100 hPa if the partial pressure of carbon dioxide is constant. We then show that the microalga can grow vigorously, reaching above 1.5 g l −1 within 4 days, under cultivations conditions analogous to these foreseen on Mars: a leachate of a Martian regolith simulant mixed with synthetic urine, under an atmosphere of 100 hPa of carbon dioxide. Conversely, a decrease in pressure altered the lipidome. Some changes may have helped preserve membrane viscosity: as an example, the MGDG-to-DGDG ratio increased. However, other alterations do not clearly point in that direction: the overall ratio of unsaturated-to-saturated fatty acids, as well as the average degree of unsaturation in thylakoid membrane lipids, for instance, only decreased with pressure when carbon dioxide (rather than carbonate) was the carbon source. Regardless, these alterations are small when compared to those induced by a change in the inorganic carbon source. Our results overall suggest that relying on a low pressure would benefit the resource-efficiency of microalgal cultivation on Mars.
ISRU and ISFR Science and Technology—A Review of the Last 15 Years Giacomo Cao, Alberto Cincotti, Alessandro Concas, Antonio Depau, Giacomo Fais, Nicola Lai, Roberta Licheri, Antonio Mario Locci, Selena Montinaro, Roberto Orrù, Gabriele Traversari Technologies, 2026 In situ resource utilization (ISRU) and in situ fabrication and repair (ISFR) are critical research and technological paradigms for future space exploration. They aim to reduce reliance on Earth-supplied materials by utilizing resources available on celestial bodies, while enabling on-site fabrication and repair through the use and processing of local resources. ISRU and ISFR are strongly interconnected, with the shared objective of enabling more sustainable and autonomous long-duration missions to the Moon, Mars, and beyond. This work presents a comprehensive and critical review of scientific and patent literature published primarily between 2010 and 2025, complemented by selected earlier seminal contributions for context. The analysis provides an integrated perspective on major technological developments, key challenges, and emerging research directions in low-gravity and microgravity environments.
Improving fermented milk antioxidant properties by functional enrichment with Vitis Vinifera leaf extract cv Monica loaded in nanovesicles Debora Dessì, Luca Casula, Giacomo Fais, Alessio Pittiu, Michele Schlich, Chiara Sinico, Francesco Lai, Giorgia Sarais Food Chemistry, 2026 Kefir is increasingly appreciated for its probiotic-rich composition and health benefits, aligning with the growing demand for functional foods. This study introduces an innovative approach to fortify kefir with grapevine leaves extract, an underutilized viticultural by-product, thereby promoting circular economy practices. The extract, characterized by a high total polyphenol content and remarkable antioxidant capacity, was analysed by HPLC-DAD, which identified caftaric acid, quercetin-3-O-glucuronide, and peonidin-3-O-glucoside as major phenolic constituents. The extract was encapsulated in nanovesicles prepared via a gentle high-shear homogenization method, a milder alternative to sonication that preserves thermosensitive compounds. The resulting nanovesicles exhibited encapsulation efficiencies ranging from 28.8 % to 73.9 % and demonstrated good physical stability. Moreover, they effectively mitigated the degradation of the extract components in simulated gastrointestinal conditions and protected enterocytes from oxidative stress in vitro. Incorporation of the loaded nanovesicles into the fermented drink enhanced its antioxidant activity in a dose-dependent manner without altering rheological properties.
A novel culture flask for clinostat-based simulation of extraterrestrial gravities Giovanni Perra, Giacomo Fais, Debora Dessì, Alessandro Concas, Paolo Follesa, Giacomo Cao, Nicola Lai Frontiers in Cell and Developmental Biology, 2026 Introduction Conventional T-flasks (T-25) filled to capacity are frequently employed to minimize shear stress arising from fluid motion during ground-based microgravity simulations using a clinostat or random positioning machine (RPM). However, this approach can introduce confounding factors, such as hypoxia and CO 2 accumulation that affect cell metabolism and function. Therefore, in vitro platform simulating microgravity is crucial to distinguish true gravity-dependent responses from culture artifacts. Here, we proposed an innovative engineered culture system (F-25) with a growth area of 25 cm 2 primarily designed for full-filled and clinostat experiments. Methods We assessed the effects of static and rotational (i.e., microgravity) full-filled cultures including conventional T-25 and eighteen customized F-25 with different medium depths, gas exchange areas and membrane types on mitochondrial function of intact C 2 C 12 myoblasts by high resolution respirometry. Results After 24 h, conventional T-25 flasks, full-filled to height of H 0 (2.25 cm) and with a hydrophobic-type gas exchange area of A 0 (0.2 cm 2 ) showed intact cellular respiration (ICR) and maximal uncoupled respiration (ET) rates that were more than twice those measured in partially-filled controls, whose values (40 ± 3 for ICR and 60 ± 4 for ET pmol O 2 s −1 10 −6 cells −1 ) remained unchanged between time zero and 24 h. At each medium depth ( 1 / 3 H 0 , 2 / 3 H 0 , and H 0 ) increasing the gas exchange area from (6A 0 , 12A 0 , and 18A 0 ) led to a progressive decrease in ICR and ET rates reaching control values. The best optimized F-25 flask configuration, combining reduced medium depth ( 1 / 3 H 0 ) with an enhanced hydrophilic gas exchange membrane of 18A 0 , maintained ICR and ET rates similar to partially-filled controls. The F-25 flask was further tested to assess mitochondrial function under simulated Mars, Moon, and space gravity conditions following 24 h of exposure. Under different extraterrestrial gravity conditions, ICR and ET rates were again twice than those of partially-filled controls but remained unchanged in optimized F-25 flask. Discussion The latter one provides a reproducible and relevant baseline, avoiding confounding factors related to O 2 delivery for clinostat-based simulations. The F-25 flask setup, which allows controlled oxygenation and minimized hydrostatic artifacts, offers a versatile platform not only for space biology, but also for hypoxia studies, 3D culture systems, and tissue engineering applications requiring a defined O 2 microenvironment.
Hybrid modeling of photocatalytic contaminant degradation using nanomaterials synthesized with microalgal extracts Federico Atzori, Bartolomeo Cosenza, Federico Zedda, Agnieszka Sidorowicz, Giacomo Fais, Giacomo Cao, Alessandro Concas Chemical Engineering Science, 2025 • AgNPs from microalgae were synthesized and used to photocatalytically oxidize BBR. • A physically consistent model well fits the experiments and identifies kinetic constants. • Operating conditions (Inputs) and kinetic constants (Outputs) used to train an ANN model. • Physically consistent augmentation of input data permits to improve ANN performance. • Augmentation of also output data further improves ANN capability to interpret experiments. Synthetic dyes released through industrial effluents pose significant environmental risks due to their persistence and toxicity. Photocatalytic degradation through metal nanoparticles offers a promising, eco-friendly remediation approach. This study presents a hybrid modeling framework for simulating the visible-light-driven degradation of Brilliant Blue R using silver nanoparticles (AgNPs) synthesized through extracts of Haematococcus pluvialis , Spirulina platensis , and Chlorella vulgaris . The biogenic AgNPs exhibited favorable physicochemical properties, including crystalline sizes of 13–16 nm and band gap energies between 2.17 and 2.33 eV. A simplified deterministic model was first developed, accounting for adsorption–desorption equilibrium and degradation kinetics, which enables analytical estimation of key kinetic parameters. These parameters were used to train artificial neural networks (ANNs) that map experimental conditions such as light intensity, dye concentration, nanoparticle dosage, and pH to degradation kinetics. To overcome the limited size of datasets obtained through experiments, a novel data augmentation strategy was implemented using Gaussian noise derived from measurement uncertainty and confidence intervals of the deterministic model’ parameters. This strategy enabled the significant augmentation of data enhancing the ANN performance. Indeed, the global mean squared error dropped from 5.6 × 10 −4 to 1.3 × 10 −5 for AgNPs from H. pluvialis , from 1.6 × 10 −2 to 3.3 × 10 −6 for C. vulgaris , and from 2.4 × 10 −3 to 4.2 × 10 −4 for S. platensis when using both input and output augmentation. The proposed hybrid framework couples mechanistic interpretability with data-driven prediction providing a reliable tool for optimizing photocatalytic degradation processes via sustainable nanomaterials of microalgal origin.
Wide Range Applications of Spirulina: From Earth to Space Missions Giacomo Fais, Alessia Manca, Federico Bolognesi, Massimiliano Borselli, Alessandro Concas, Marco Busutti, Giovanni Broggi, Pierdanilo Sanna, Yandy Marx Castillo-Aleman, René Antonio Rivero-Jiménez, Antonio Alfonso Bencomo-Hernandez, Yendry Ventura-Carmenate, Michela Altea, Antonella Pantaleo, Gilberto Gabrielli, Federico Biglioli, Giacomo Cao, Giuseppe Giannaccare Marine Drugs, 2022