Microalgae have emerged as sustainable feedstocks due to their ability to fix CO₂ during cultivation, rapid growth rates, and capability to produce a wide variety of metabolites. Several microalgae accumulate lipids in high concentrations, especially triglycerides, along with lipid‐soluble, photoactive pigments such as chlorophylls and derivatives. Microalgae‐derived triglycerides contain longer fatty acid chains with more double bonds on average than vegetable oils, allowing a higher degree of post‐functionalization. Consequently, they are especially suitable as precursors for materials that can be used in 3D printing with light. This work presents the use of microalgae as “biofactories” to generate materials that can be further 3D printed in high resolution. Two taxonomically different strains —Odontella aurita (O. aurita, BEA0921B) and Tetraselmis striata (T. striata, BEA1102B)— are identified as suitable microalgae for this purpose. The extracts obtained from the microalgae (mainly triglycerides with chlorophyll derivatives) are functionalized with photopolymerizable groups and used directly as printable materials (inks) without the need for additional photoinitiators. The fabrication of complex 3D microstructures with sub‐micron resolution is demonstrated. Notably, the 3D printed materials show biocompatibility. These findings open new possibilities for the next generation of sustainable, biobased, and biocompatible materials with great potential in life science applications.

In the present study, the chemical composition of the microalga Euglena cantabrica was investigated. The extraction of bioactive compounds was done using pressurized liquid extraction (PLE) at different temperatures (40–180 °C) and using green solvents (ethanol-water mixtures). A statistical design of experiments was used to optimize the maximum antioxidant capacity of the extracts by response surface methodology. The antioxidant capacity was determined through the inhibition of 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, while the chemical analyses of the extracts were carried out using different chromatographic techniques. Chlorophylls and carotenoids were analyzed by high-performance liquid chromatography coupled to a diode array detector and mass spectrometry (HPLC-DAD-MS/MS) and carbohydrates by gas chromatography with flame ionization detection (GC-FID) and high-pressure size-exclusion chromatography coupled to an evaporative light-scattering detector (HPSEC-ELSD). The results showed different possibilities for the extraction conditions, depending on the desired bioactivity or chemical composition. Briefly, (i) mixtures of ethanol-water containing around 40% ethanol at 180 °C gave the best antioxidant capacity, (ii) mixtures containing around 50% ethanol at 110 °C gave the best yield of β-glucan paramylon, and (iii) the use of pure ethanol at a low temperature (40 °C) is the best choice for the recovery of carotenoids such as diatoxanthin. Summing up, E. cantabrica seems to be a good candidate to be used in biorefinery to obtain different bioactive compounds.

Optical Camera Communication (OCC) systems have a potential application in microalgae production plants. In this work, a proof-of-concept prototype consisting of an artificial lighting photobioreactor is proposed. This reactor optimises the culture’s photosynthetic efficiency while transmitting on-off keying signals to a rolling-shutter camera. Upon reception, both signal decoding and biomass concentration sensing are performed simultaneously using image processing techniques. Moreover, the communication channel’s theoretical modelling, the data rate system’s performance, and the plant distribution requirements and restrictions for a production-scale facility are detailed. A case study is conducted to classify three different node arrangements in a real facility, considering node visibility, channel capacity, and space exploitation. Finally, several experiments comprising radiance evaluation and Signal-to-Noise Ratio (SNR) computation are performed at different angles of view in both indoor and outdoor environments. It is observed that the Lambertian-like emission patterns are affected by increasing concentrations, reducing the effective emission angles. Furthermore, significant differences in the SNR, up to 20 dB, perceived along the illuminated surface (centre versus border), gradually reduce as light is affected by greater dispersion. The experimental analysis in terms of scattering and selective wavelength attenuation for green (Arthrospira platensis) and brown (Rhodosorus marinus) microalgae species determines that the selected strain must be considered in the development of this system.

Curdlan, a β-1,3/1,6-glucan found in Alcaligenes faecalis (A. faecalis) wall, activates innate and humoral immunity. The aim of this study is to evaluate whether pretreated rats with A. faecalis A12C could prevent sepsis disturbances and identify the immunomodulatory mechanisms involved. Experiments occurred in two stages: a survival study with 16 rats randomly divided into septic (SC) (n = 8) and septic pretreated (SA) (n = 8) groups and 45 rats divided into four groups: healthy (AGUSAN) (n = 9), septic (AGUIC) (n = 13), septic pretreated (AGUIA) (n = 14), and healthy pretreated (AGUSTO) (n = 9). Sepsis was induced by cecal ligation and puncture after 30 days of A. faecalis A12C pretreatment or without. SA group had a higher survival rate of 58% vs. 16% for SC group (P < 0.05). Overall, AGUIA showed better status than AGUIC (P < 0.01). Higher monocytosis was found in AGUIA and AGUSTO vs. AGUIC and AGUSAN, respectively (P < 0.05). A gradual increase in curdlan fecal concentration was observed in AGUIA during pretreatment. Fecal concentrations of Escherichia coli significantly decreased in AGUIA and AGUSTO. Bacterial load in urine, peritoneal lavage fluid (PLF), and bronchoalveolar lavage fluid (BALF) decreased (P < 0.05) in AGUIA vs. AGUIC. Finally, lower inflammation was observed in serum, BALF, and PLF, with reduced IL-6, IL-10, IL-1β, and TNF-α, along with less damage in lungs and peritoneum in AGUIA vs. AGUIC. These findings suggest the connection between curdlan—produced by A. faecalis A12C—with the immune system and the reduction in severity of experimental sepsis.

Malignant melanoma is skin cancer arising from genetically altered melanocytes. Recently, a complex relationship between melanoma and chronic inflammation has been highlighted, representing an excellent condition for tumor development. Microalgae have been shown to be a promising source of bioactive compounds for drug discovery. In this study, we investigated Halamphora sp. (BEA0050) to identify possible compounds with immunomodulatory activity. The most active fraction (fraction D) showed anti-inflammatory activity against human melanoma cancer cells (A2058) stimulated using lipopolysaccharide (LPS) to induce an inflammatory phenotype. Chemical profiling of the bioactive fraction using chromatography and high-resolution mass spectrometry (UHPLC-HR-MS) revealed hydroxypheophorbide a, a breakdown product of chlorophyll a. In order to investigate the mechanism of action, the TNF-α release was detected through ELISA sandwich assays in A2058 cells and through confocal microscopy in LPS-stimulated HaCaT cells. Gene expression of principal pro-inflammatory cytokines and pathways was detected through real-time PCR, which showed the down-regulation of the inflammatory pathway in LPS-induced A2058 and HaCaT cells treated with 12.5 µg/mL of fraction D. This study reports for the first time the anti-melanoma and anti-inflammatory activities of Halamphora sp., identifying protein mediators and highlighting its biotechnological potential.

Microalgae hold great potential towards pharmaceutical and nutraceutical sectors due to their substantial content of highly functional bioactive compounds. To assess their potential as a sustainable source of valuable products, 10 cyanobacterial and 10 eukaryotic microalgal strains belonging to different taxonomic groups (Chlorophyta, Cyanophyta, Euglenophyta, Heterokontophyta and Rhodophyta) were screened for their biochemical profile, antioxidant and antimicrobial activity against Staphylococcus aureus. Total phenol content and antioxidant activity were positively correlated (r = 0.69, p < 0.01), with the highest values observed in Euglena cantabrica, Haematococcus pluvialis, and Chrysoreinhardia giraudii. HPLC-PAD pigment analysis revealed species-specific profiles, with β,β-carotene as major carotenoid in most cyanobacteria, whereas neoxanthin, violaxanthin and lutein were predominantly present in Chlorophyta, and fucoxanthin was the main carotenoid in C. giraudii, Entomoneis sp. and Isochrysis galbana. Protein content ranged from 9.2 ± 0.4% to 57.6 ± 0.5% with the highest levels in the cyanobacteria Microcystis aeruginosa, Nostoc sp., Cylindrospermum stagnale, Anabaena minutissima, and Arthrospira platensis. Multivariate analysis differentiated cyanobacteria and eukaryotes based on their fatty acid profiles. Organic extracts from 15 species showed inhibitory effects against S. aureus with MIC50 < 1024 µg/mL. The eukaryotes Entomoneis sp., C. giraudii, I. galbana, Picochlorum sp. and the cyanobacteria C. stagnale and Nodularia sp. exhibited the strongest inhibitory effects on bacterial growth. In conclusion, E. cantabrica and C. giraudii stood out for their high antioxidant activity and significant antimicrobial effects, respectively, highlighting their potential as valuable sources of bioactive compounds.