Search Results (187)

Synechocystis sp. PCC 6803 is a photosynthetic microbe with high potential for capturing excessive atmospheric carbon while generating valuable bioproducts, like glucose. Current cultivation technologies remain expensive, closed-source, and poorly suited for downstream processing. This study presents a low-cost, open-source bioreactor platform with integrated modules for Synechocystis cultivation and glucose extraction. The system incorporates a photobioreactor, a lysis module, and a pressure-driven filtration setup. Optical density was continuously monitored using a custom-built module, and glucose was quantified using high-performance liquid chromatography (HPLC). Under an incident light intensity of approximately 400 $\mathsf{\mu }\mathrm{m}\mathrm{o}\mathrm{l}$${\mathrm{m}}^{-2}$${\mathrm{s}}^{-1}$, cultures reached a biomass productivity of 90 mg ${\mathrm{L}}^{-1}{\mathrm{day}}^{-1}$, with a specific growth rate of $0.166{\mathrm{day}}^{-1}$ and glucose concentrations up to $5.08$$\mathrm{m}\mathrm{g}{\mathrm{L}}^{-1}$. A model was developed to predict the growth based on measured environmental parameters, achieving a strong predictive accuracy with a mean absolute error and variance of $0.0009\pm 0.0003$. The system demonstrates up to 65% reduction in cost compared to commercial alternatives. This modular platform provides an accessible solution for biomanufacturing research and serves as a template for sustainable cyanobacteria-derived glucose production. Full article

Microalgae and cyanobacteria produce extracellular polysaccharides that are exuded and released into the medium, typically referred to as exopolysaccharides (EPSs). Microalgae-derived EPSs have garnered attention in the last decade, as they may exhibit specific bioactivities and therefore hold promise for biofunctional applications in the biomedical, food, agricultural, and cosmetic fields. In cosmetic formulations, EPSs can be included both to improve techno-functional and sensorial properties and as active ingredients, showing great potential in the preparation of cosmetic products aimed at hydration and anti-aging. This review surveys the literature on the potential of EPS microalgae in skin care and cosmeceutical formulations to reveal a material that is sometimes discarded during the microalgae cultivation process and that can be recovered for cosmetic use. The conclusions of this review highlight that EPSs from microalgae and cyanobacteria exhibit different physicochemical and biological functionalities, making them attractive for potential exploitation as commercial sources of new polysaccharides. Full article

Cyanobacteria are a natural source of bioactive compounds increasingly recognized for their anti-inflammatory properties. In the Euganean Thermal District (Italy), thermal muds, used to cure arthro-rheumatic diseases, are prepared using natural clay and thermal water, resulting in a mature mud characterized by a complex microbial biofilm dominated by Cyanobacteria. Among these, Phormidium sp. ETS-05 has been shown to contribute to the therapeutic properties of the mud, mainly through the production of bioactive compounds such as exopolysaccharides (EPSs) and glycoglycerolipids (GLs). In contrast, the role of biomolecules from Thermospirulina andreolii ETS-09 and Kovacikia euganea ETS-13, also abundant in mature muds but at higher maturation temperatures, has not been investigated. This study focuses on the lipid profiles of these cyanobacteria, cultivated under temperature conditions that mimic their natural environment and that are different for the three species. Lipid extracts were analyzed for GLs classes and fatty acid composition, and their anti-inflammatory potential was assessed in vivo using a zebrafish inflammation model. All extracts showed anti-inflammatory activity with Phormidium sp. ETS-05 displaying the highest lipid content and the most rapid and potent beneficial effect, likely due to the specific composition of its GLs, presenting the greatest abundance of polyunsaturated fatty acids. These findings provide new insights into the biological basis of the therapeutic effects of Euganean muds and emphasize the importance of maturation conditions for cyanobacterial growth and bioactive lipid production. Full article

Reclaimed land refers to artificially created soil formed by filling in seawater, leading to rapid ecological changes. Undeveloped reclaimed areas offer opportunities to explore previously unknown soil ecological resources. The Shihwa reclaimed land is an undeveloped area where microbiome-based studies of the microbial community have not yet been conducted. The soil from the Sihwa reclaimed land (SR, SL) showed higher pH (8.9), EC (7.5 dS/m), and Na⁺ content (13.4 cmol⁺/kg), but lower levels of organic matter and phosphorus compared to typical agricultural soils (NL, NS). These unfavorable conditions had a negative effect on lettuce growth, as both fresh and dry weights in the SL treatment (32.5 g and 0.39 g, respectively) were significantly lower than those in the NL treatment (40.4 g and 0.45 g). At the phylum level, Actinobacteria (51.6%) dominated the original reclaimed soil (SR), but after lettuce cultivation (SL), there was an increase in Cyanobacteria (25.3%) and Proteobacteria (29.4%). At the order level, Streptomycetales (35.2%) and Bacillales (13.5%) were predominant in SR, whereas in SL, Oscillatoriales (23.5%)—which have photosynthetic ability—as well as organic matter-degrading orders such as Rhodobacterales and Flavobacteriales, became dominant. For the eukaryotic community at the phylum level, Ascomycota was predominant in all samples; however, in NL, the relative proportions of Chlorophyta (22%) and Mucoromycota (8.9%) were higher, indicating increased diversity. At the order level, Eurotiales (28.5%), Hypocreales (20.2%), and Wallemiales (14.4%) were predominant in SR, but after lettuce cultivation, Wallemiales disappeared and Eurotiales increased to 40.0%. Additionally, Glomerellales and Sordariomycetes_o were detected only in SL and NL, suggesting that symbiotic fungal activity in the rhizosphere was promoted. Full article

Investigating the microbial community structure and stress-tolerance mechanisms in the rhizospheres of salt-adapted plants along saline lakes is critical for understanding plant–microbe interactions in extreme environments and developing effective strategies for saline–alkaline soil remediation. This study explored the rhizosphere microbiomes of four salt-adapted species (Suaeda glauca, Artemisia carvifolia, Chloris virgata, and Limonium bicolor) from the Yuncheng Salt Lake region in China using high-throughput sequencing. Cultivable salt-tolerant plant growth-promoting rhizobacteria (PGPR) were isolated and characterized to identify functional genes related to stress resistance. Results revealed that plant identity and soil physicochemical properties jointly shaped the microbial community composition, with total organic carbon being a dominant driver explaining 17.6% of the variation. Cyanobacteria dominated low-salinity environments, while Firmicutes thrived in high-salinity niches. Isolated PGPR strains exhibited tolerance up to 15% salinity and harbored genes associated with heat (htpX), osmotic stress (otsA), oxidative stress (katE), and UV radiation (uvrA). Notably, Peribacillus and Isoptericola strains demonstrated broad functional versatility and robust halotolerance. Our findings highlight that TOC (total organic carbon) plays a pivotal role in microbial assembly under extreme salinity, surpassing host genetic influences. The identified PGPR strains, with their stress-resistance traits and functional gene repertoires, hold significant promise for biotechnological applications in saline–alkaline soil remediation and sustainable agriculture. Full article

Cyanobacteria-based bioinoculants represent a sustainable solution for enhancing soil fertility and crop productivity. This research assessed the biofertilizing potential of two indigenous nitrogen-fixing cyanobacteria strains (Nostoc punctiforme Har. and Anabaena cylindrica Lemmerm.) on tomato growth and yield. A greenhouse experiment was conducted to study their effects on soil properties, plant growth and physiology, and fruit yield/quality. The strains were applied individually, as a consortium, or combined with organic or mineral fertilizers at half the standard dose (50%). All bioinoculants improved soil fertility, plant growth, and fruit yield/quality compared to the control. The most significant improvement was observed in the consortium amended with 50% of conventional fertilizer (compost or NPK), compared with individual strains. Correlation analysis revealed strong positive associations between photosynthetic pigments, plant productivity, and fruit biochemical traits, indicating coordinated physiological responses under the applied treatments. The results demonstrated that the consortium of diazotrophic terrestrial cyanobacteria possesses tomato biofertilizer properties that can be efficiently used in crop production. These findings suggest that such formulations offer a cost-effective approach to tomato cultivation and present a sustainable alternative for integrated and optimized fertilizer management. Full article

Salinity serves as a critical environmental factor influencing the physiological and morphological characteristics of Spirulina, a filamentous cyanobacterium used for food production and commercial purposes. This study examined a Spirulina strain’s responses to different salinity levels (10–45 ppt) through three independent laboratory experiments that determined growth, productivity, and size structure. Growth across salinity treatments was assessed by monitoring optical density in 24-well microplates over 20 days and estimating specific growth rates using a logistic growth model. Primary productivity under different salinity and light conditions was measured using light and dark bottle experiments to calculate gross primary productivity (GPP) and to estimate photosynthetic efficiency through linear regression of GPP against light intensity. The size structure was assessed through tube-based experiments and image analysis, with organism sizes categorized and analyzed to identify salinity-induced patterns in filament structure. The study demonstrated that the Spirulina strain achieved its greatest growth at 10 ppt yet produced the highest photosynthetic efficiency between 27 and 45 ppt because it reallocated energy during salinity stress. The morphological analysis revealed that the Spirulina strain produced medium-sized filaments between 400 and 799 µm at elevated salinity levels, and our analysis confirmed substantial variations in size structure. The Spirulina strain demonstrates both physiological and morphological plasticity when exposed to salinity changes. The cultivation of the Spirulina strain at 27 ppt provides conditions that support moderate growth, enhanced productivity, and manageable morphological shifts while using its natural salinity tolerance to improve the efficiency and scalability of production for diverse biotechnological applications. Full article

Photosynthetic organisms such as cyanobacteria have the potential for the sustainable production of complex organic molecules due to their ability to use light as an energy source to fix CO₂ and assimilate inorganic nutrients. Over the past decade, large efforts have been put into the metabolic engineering of cyanobacteria to produce various compounds such as alcohols, isoprenoids, biopolymers, and recombinant proteins. Forskolin is a structurally complex labdane-type diterpenoid with eight chiral carbon atoms and is naturally produced in the root cork of the plant Plectranthus barbatus. Forskolin is a potent cAMP activator indicated as a pharmaceutical for a variety of diseases. In the plant, forskolin biosynthesis from geranylgeranyl diphosphate involves six enzymes: two terpene synthases, three cytochrome P450s, and a single acetyltransferase. In this work, we express all six biosynthetic genes from Plectranthus barbatus in Synechocystis sp. PCC. 6803 and demonstrate heterologous production of this complex diterpenoid in a phototroph cyanobacterium. Forskolin titers reached 25.0 ± 4.4 µg/L and the forskolin was entirely secreted into the media. The forskolin-producing Synechocystis strain and empty vector control were cultivated in a photobioreactor for 8 days. Both strains showed similar chlorophyll a contents, and the forskolin-producing strain reached a slightly higher OD₇₃₀ than the control. Forskolin began accumulating in the supernatant after 4 days and increased over time. These results indicate that forskolin production did not negatively impact cell growth. Full article

Large-scale cultivation of cyanobacteria is often limited by the high cost of synthetic culture medium and the environmental impact of nutrient consumption. Cheese whey, a major agro-industrial waste product, is rich in organic and inorganic nutrients, making it a promising low-cost alternative for microbial growth while addressing waste bioremediation. This study investigates the growth performance and the biochemical composition of four different cyanobacterial species (Phormidium sp., Synechocystis sp., Chlorogloeopsis fritschii, and Arthrospira platensis), cultivated in cheese whey (CW). Pretreated CW was used at 20% and 100% v/v concentrations. All species grew satisfactorily in both concentrations, reaching biomass above 4 g L⁻¹ (in 100% v/v CW) and 2 g L⁻¹ (in 20% v/v CW). The highest μ_max value (0.28 ± 0.02 d⁻¹) was presented by Synechocystis sp. grown in 20% CW. Waste bioremediation of both 20 and 100% v/v CW demonstrated effective nutrient removal, with COD removal exceeding 50% for most species, while total nitrogen (TN) and total phosphorus (TP) removals reached up to 33% and 32%, respectively. Biochemical composition analysis revealed high carbohydrate and protein content, while lipid content remained below 15% in all cases. Interestingly, C. fritschii accumulated 11% w/w polyhydroxyalkanoates (PHAs) during the last day of cultivation in 20% v/v CW. These findings highlight the potential of C. fritschii as a valuable candidate for integration into bioprocesses aimed at sustainable bioplastic production. Its ability to synthesize PHAs from agro-industrial waste not only enhances the economic viability of the process but also aligns with circular economy principles. This study is a primary step towards establishing a biorefinery concept for the cultivation of cyanobacterial species in cheese whey-based wastewater streams. Full article

This review examines the history of consumption, life cycle, and culture conditions of seven edible mucilaginous terrestrial cyanobacterial strains—Nostoc flagelliforme, Nostoc commune, Nostoc sphaeroides, Nostoc sphaericum, Nostoc verrucosum, Aphanothece sacrum, and Nostochopsis lobatus—as resilient and sustainable food sources in the face of climate change. Traditionally consumed across various cultures and known for their resilience in extreme environments, these cyanobacteria offer high nutritional value, including proteins, vitamins, and essential fatty acids, making them promising candidates for addressing food security. Their ability to fix nitrogen reduces reliance on synthetic fertilizers, enhancing agricultural applications by improving soil fertility and minimizing dependence on fossil fuel-derived chemicals. Unlike conventional crops, these cyanobacteria require minimal resources and do not compete for arable land, positioning them as ideal candidates for low-impact food production. Despite these advantages, the review highlights the need for scalable and cost-effective cultivation methods to fully realize their potential in supporting a resilient global food supply. Additionally, it underscores the importance of ensuring their safety for consumption, particularly regarding toxin content. Full article

The dairy industry generates substantial nutrient-rich wastewater, posing environmental challenges if discharged untreated. This study explores the potential of using the cyanobacterium Arthrospira platensis for nutrient recovery from dairy wastewater, precisely the liquid biogas digestate (BD). The research investigates the feasibility of utilising BD and electrodialysis-concentrated BD (BD concentrate) as alternative media for A. platensis cultivation, with a focus on biomass productivity, nutrient uptake, and high-value product formation. Batch and continuous cultivation modes were employed. In batch experiments, biomass productivity was in the ratio of 0 and 0.27 g L⁻¹ d⁻¹, which was 8–100% lower than simulated values for all five tested media compositions. Phosphate fixation was limited with no fixation during batch cultivation and 8–69% during continuous cultivation, likely due to suboptimal N/P ratios, while ammonium removal remained consistently high (>98%). Phycocyanin yield decreased significantly by 92% at high BD concentrate concentrations compared to standard media. Continuous cultivation with 50% BD concentrate improved biomass productivity to 1.02 g L⁻¹ d⁻¹ and pigment yield to 107.9 mg g⁻¹, suggesting a sufficient supply of nutrients. The findings highlight the potential of BD-based media for nutrient recovery but emphasise the need for optimisation strategies, such as nutrient supplementation and microbial adaptation, to enhance performance. Full article

In response to the growing market demand for Litopenaeus vannamei, a variety of single-species, high-density, intensive, and high-yield aquaculture modes have arisen. These aquacultural systems are teeming with microorganisms, which play roles in water quality and host health. To uncover the prokaryotic community composition across cultivation modes, we investigated the prokaryotic community composition at two fractionated sizes in the water of three culture modes of Litopenaeus vannamei, including high-level pond culture, biofloc technology (BFT), and pond culture. The 16S rRNA gene high-throughput sequencing results indicated that the taxa particularly enriched by high-level pond culture modes were mainly Deltaproteobacteria, while Alpha- and Gammaproteobacteria and Flavobacteria were enriched in the BFT culture modes. The pond culture enriched Bacteroidetes, Sphingobacteriia, Actinobacteria, and Cyanobacteria. PCoA analysis showed that for the pond samples, there were significant differences in the community composition compared with the samples from the other two modes. However, the high-level pond and biofloc samples showed similar community compositions. Furthermore, Canonical Correspondence Analysis (CCA) and Variance Partitioning Analysis (VPA) revealed that NH₄⁺-N, salinity (Sal), and NO₃⁻-N were key factors affecting the aquaculture communities. Full article

Microorganisms in high-salinity environments play a critical role in biogeochemical cycles, primary production, and the biotechnological exploitation of extremozymes and bioactive compounds. The main challenges in current research include isolating and cultivating these microorganisms under laboratory conditions and understanding their complex adaptive mechanisms to high salinity. Currently, universally recognized protocols for isolating microalgae and cyanobacteria from salt pans, salterns, and similar natural habitats are lacking. Establishing axenic laboratory cultures is essential for identifying new species thriving in high-salinity environments and for exploring the synthesis of high-value metabolites by these microorganisms ex situ. Our ongoing research primarily focuses on photosynthetic microorganisms with significant biotechnological potential, particularly for skincare applications. By integrating data from the existing literature with our empirical findings, we propose a standardized pipeline for the isolation and laboratory cultivation of microalgae and cyanobacteria originating from aqueous environments characterized by elevated salt concentrations, such as solar salterns. This approach will be particularly useful for researchers working with microorganisms adapted to hypersaline waters. Full article

Regarded as a panacea in non-traditional medicine, Spirulina (“Arthrospira platensis”) refers to cyanobacteria that are highly consumed due to their mineral and bioactive compounds. Despite its wide popularity and availability, Spirulina is often present on the market as an insufficiently regulated dietary supplement with scarce quality control and has high batch-to-batch variability. The present study aims to provide the first comprehensive survey of the Spirulina commercialized on the Romanian market. Therefore, a highly diverse sample set, including an in-house cultivated sample, was analyzed and compared in regard to the ¹³C isotopic signature and the elemental profile of twenty-three elements, including macro-nutrients (Na, Mg, Ca, and K), essential trace elements (e.g., Fe, Zn, Co, and Mn), and possible toxic contaminants (e.g., As, Cd, Cr, and Pb). Results confirmed the potency of Spirulina as a proper mineral supplement source. The in-depth analysis performed in the present work takes into account several critical factors, like formulation, packaging type and material, geographical origin, and labeled growing system, in order to assess whether these marketing strategies are supported. Additionally, the statistical relationships among the price, isotope, and elemental determinations were assessed by Pearson correlation coefficients and subsequently discussed in regard to the biochemical and physiological processes. Full article

Arnebia euchroma (Royle) Johnst. has high medicinal and economic value, but in recent years, wild resources of this species have been depleted and the quality of artificially cultivated A. euchroma has been poor. The endophyte community of medicinal plants is rich, serving as an internal resource that promotes the growth of medicinal plants and the accumulation of secondary metabolites, and has important potential application value in improving the quality of medicinal materials. A. euchroma cultivars and wild varieties contain abundant endophyte communities and metabolites in different tissues. However, the relationships between A. euchroma endophytes and metabolites with different growth patterns and different tissue sites remain unclear. In this study, microbiome analysis and metabolomics were used to analyze the diversity of endophytes in the root and leaf tissues of cultivated and wild A. euchroma and their correlations with metabolites. The results revealed that the diversity of endophytes in A. euchroma was different from that in wild A. euchroma and that there was tissue specificity among different tissues. A species composition analysis revealed that the dominant endophytic fungi belonged to Ascomycota and Basidiomycota, and the dominant endophytic bacteria belonged to Proteobacteria and Cyanobacteria. A total of 248 metabolites, including quinones, flavonoids, alkaloids, organic acids, sugars, amino acids, coumarins, sterols, terpenoids, polyphenols, fatty ketones, and their derivatives, were identified in positive ion mode via LC–MS/MS. According to their different growth patterns and associated tissue parts, 9 differentially abundant metabolites were screened between AEZ-L (cultivated leaf tissue of A. euchroma) and AEY-L (wild leaf tissue of A. euchroma), 6 differentially abundant metabolites were screened between AEZ-R (cultivated root tissue of A. euchroma) and AEY-R (wild root tissue of A. euchroma), and 104 differentially abundant metabolites were screened between AEZ-R and AEZ-L. Eighty-two differentially abundant metabolites were screened between AEY-R and AEY-L. The contents of eight naphthoquinones in AEZ-R and AEY-R were determined via HPLC. The contents of β,β’-dimethylacrylylakanin in wild A. euchroma were greater than those in cultivated A. euchroma. A correlation analysis revealed that the dominant endophytes in the four groups were significantly correlated with a variety of metabolites, and the eight naphthoquinones in the root tissue were also significantly correlated with the dominant endophytes. The diversity of the A. euchroma endophyte community differed across different growth patterns and different tissue parts. There were significant differences in the relative contents of A. euchroma metabolites in different tissues. A correlation analysis verified the correlation between A. euchroma endophytes and metabolites. Full article