Search Results (136)

Cyanobacteria (also called blue-green algae)-based dietary supplements are commonplace, but cyanobacteria-enhanced foods, such as spirulina crackers, are just appearing on New Zealand supermarket shelves. While much research has been devoted to consumer attitudes towards macro-algae-based products, little research has been devoted to micro-algae-based or cyanobacteria-enhanced consumer products. The current study, following the Capability–Opportunity–Motivation to Behaviour theory, examines likely consumer drivers of favouring or disfavouring spirulina crackers. These drivers include food neophilia, food neophobia, perception of sustainability and health-related product attributes, involvement with algae and an exploratory driver, snacking behaviour. Fully supported drivers (related to increased favour and decreased disfavour) included food neophilia and perception of sustainability and health-related product attributes. Algae involvement was only related to increased favour, and food neophobia was not supported. Surprisingly, snacking behaviour was related to increased disfavour of spirulina crackers. Both theoretical and managerial implications are offered. Full article

The demand for sustainable animal production is increasing. Microalgae such as Chlorella and Spirulina show promise as sustainable and functional ingredients in animal (poultry) feed. However, little is known about consumer perceptions regarding the use of algae in broiler diets and potential effects of algae on chicken meat. Residents of Flanders (Belgium) were surveyed to evaluate consumer knowledge, attitudes and willingness to buy chicken meat produced with algae-supplemented feed. Demographic data were collected, and both descriptive and inferential statistics were applied to assess influencing factors (n = 275 respondents who purchase chicken meat). While most respondents (69.6%) had tasted macroalgae (seaweed), only 11.4% and 24.6% indicated having tasted Chlorella and Spirulina before, respectively. Health, taste and safety were the most important drivers for consuming algae. Meat quality was the most important factor when purchasing chicken meat, while organic production was least valued. Regarding algae-fed chicken, 72.5% expressed willingness to purchase meat labeled as such, and 83.7% would buy algae-fed chicken regardless of its color. Sustainability beliefs significantly influenced willingness to accept a yellower meat color (β = 0.42 to 0.66, p < 0.001). Educational level and age also played a role, with higher-educated consumers showing greater acceptance. The influence of age was also related to the price of the meat, with consumers over 30 expressing a greater willingness to pay more than young people (under 30). Despite limited general knowledge about microalgae, the consumers surveyed are open to the idea of algae-fed chicken meat, particularly when it is framed as more sustainable. Clear ingredient labeling and consumer education may further support market acceptance. Full article

High ash content in algal biomass limits its suitability for biofuel production by reducing combustion efficiency and increasing fouling. This study presents a green deashing strategy using nitrilotriacetic acid (NTA) and deionized (DI) water to purify Scenedesmus algae, which was selected for its high ash removal potential. The optimized sequential treatment (DI, NTA chelation, and DI+NTA treatment at 90–130 °C) achieved up to 83.07% ash removal, reducing ash content from 15.2% to 3.8%. Elevated temperatures enhanced the removal of calcium, magnesium, and potassium, while heavy metals like lead and copper were reduced below detection limits. CHN analysis confirmed minimal loss of organic content, preserving biochemical integrity. Unlike traditional acid leaching, this method is eco-friendly after three cycles. The approach offers a scalable, sustainable solution to improve algal biomass quality for thermochemical conversion and supports circular bioeconomy goals. 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

Conservation units (CUs) play a fundamental role in maintaining and conserving biodiversity, and are important in preserving streams, reducing impacts from human activities and increasing water availability beyond the boundaries of the reserves. However, knowledge about the phytoplankton biodiversity of ecosystems in CUs is scarce. This study evaluated how environmental integrity alters microphytoplankton communities in extractive CUs and their surroundings in the southwestern Brazilian Amazon. Our results demonstrated that the streams exhibited distinct physicochemical and hydrological characteristics, representing spatially heterogeneous environments. Differences in habitat integrity values altered species composition in streams within and outside conservation units. Local beta diversity (LCBD) was negatively influenced by habitat integrity, indicating that sites with greater habitat integrity did not always present a greater number of unique species. The species Trachelomonas hispida, Gyrosigma scalproides and Spirogyra sp. were the ones that contributed the most to beta diversity. However, the phytoplankton species that contributed most to beta diversity were not always associated with streams with greater integrity, indicating that even environments that are less intact play a relevant role in maintaining species richness and beta diversity of microphytoplankton. Factors such as habitat integrity, pH, temperature and dissolved oxygen were the main influencers of microphytoplankton in the streams. Thus, the streams of both CUs and their surroundings, despite their physical–chemical and hydrological differences, effectively contribute to the high richness and beta diversity of regional microphytoplankton. Full article

The nutrient-rich composition of seaweeds and lichens makes them well-suited for agricultural applications. Their use as alternatives to synthetic fertilizers contributes to sustainable agricultural production, enabling farmers to adopt ecological practices while maintaining or increasing crop productivity. This review aims to highlight the status and trends of research, along with a literature analysis on the application of these biomasses in sustainable agriculture. A bibliometric analysis was performed based on two databases (Scopus and Web of Science) to overview the main research topics regarding the use of biomasses studied in agriculture, thus providing useful information for future research. The biochemical composition and agricultural applications of these biomasses have been highlighted. The analysis shows that these biomasses are rich of nutrient compounds, revealing their roles and mechanisms of action on the chemical, nutritional properties, and soil microbial activities and their effect on plant growth, using various extraction and application methods. It also highlighted the potential of seaweeds for protection against biotic and abiotic stresses. In light of all the data presented in this review, it is possible to stimulate farmers’ interest in using seaweeds and lichens as natural fertilizers, with a focus on sustainable and ecological agriculture mainly in developing countries. Full article

Bangiales are photosynthetic organisms that grow in the intertidal zone, a region characterized by fluctuating environmental conditions. The order comprises genera exhibiting two different morphological variations, filamentous and foliose. It was recently demonstrated that the filamentous alga ‘Bangia’ sp. ESS1 possesses the intrinsic ability to “memorize” an experience of prior heat stress to enhance its survival under subsequent, normally lethal, high-temperature conditions via the acquisition of heat stress tolerance. Here, we investigated whether foliose red algae can similarly memorize heat stress to acquire thermotolerance. When Pyropia yezoensis thalli were primed with non-lethal, high-temperature treatments (22 and 25 °C) for 7 days, vegetative cells subsequently triggered with a normally lethal temperature of 30 °C showed dramatically increased survival rates, indicating that P. yezoensis can acquire heat stress tolerance via exposure to non-lethal high temperatures. In addition, when 22 °C-primed thalli were incubated at 15 °C for recovery, vegetative cells survived subsequent incubation at 30 °C; their survival rates varied depending on the duration of recovery. These findings indicate that, like filamentous red algae, the foliose species P. yezoensis memorizes heat stress to acquire tolerance to recurrent thermostress. The identification of heat stress memory in foliose Bangiales lays a foundation for improving the heat stress tolerance of these important algae, supporting the sustainability of the nori mariculture industry. Full article

The Portuguese coast forms a key biogeographic transition zone where co-occurring kelp species show limited vertical overlap. This study aimed to understand whether temperature and light responses help explain the vertical niche differentiation of Laminaria ochroleuca, Saccorhiza polyschides, and Phyllariopsis brevipes. Results revealed that P. brevipes, despite occupying the southernmost range, showed a low thermal tolerance: 27 °C significantly increased respiration rates, indicating metabolic stress, and exposition at 30 °C caused physiological stress. In contrast, L. ochroleuca and S. polyschides exhibited a greater thermal resilience but displayed high light requirements, with evident stress at 30 °C. These results suggest that light availability may play a key role in shaping vertical zonation in a climate warming scenario, with species adapted to low light occupying deeper subtidal zones. S. polyschides, a high light-requiring species, dominates the shallow subtidal region, while L. ochroleuca, also high light-requiring and temperature-tolerant, is abundant in both intertidal pools and shallow subtidal habitats. These findings raise new hypotheses regarding future distribution patterns under climate change: while L. ochroleuca may continue expanding polewards and potentially replace other Laminaria spp. at shallow depths, low-light-adapted, cold-water species may retain a competitive advantage in deeper zones. Full article

Microcystis aeruginosa is a cyanobacterium frequently associated with toxic blooms in eutrophic freshwater systems. Certain strains produce microcystins (MCs), a group of hepatotoxins with significant ecological and public health implications. In this study, we examined the quantitative response of a temperate native M. aeruginosa strain to combinations of temperature (26, 30, and 36 °C), light intensity (30, 50, and 70 µmol photons·m⁻²·s⁻¹), and N:P ratio (10, 100, 150), using a full-factorial experimental design. Growth parameters (µ, lag phase duration, and maximum cell density), chlorophyll-a production, and MC-LR synthesis were modeled using Gompertz, linear, and dynamic approaches. High temperature and irradiance increased the specific growth rate but decreased final biomass, while elevated N:P ratios shortened the lag phase. MC-LR production peaked under low temperature, low irradiance, and low N:P ratio. Although MC-LR synthesis did not correlate positively with growth rate, and the environmental conditions maximizing growth differed from those enhancing toxin production, a population-level coupling between both processes was observed using the Long model. These findings suggest that MC-LR synthesis in M. aeruginosa is not merely a metabolic by-product of growth, but a context-dependent trait with potential adaptive significance. Full article

Seaweeds represent a vital yet often understudied component of the diet and cultural heritage of many coastal communities globally. This study investigated seaweed consumption practices in coastal communities of Tawi-Tawi, Philippines, through one-to-one interviews (n = 280) and focus group discussions (n = 7). The study revealed that nearly all (99%) of the population consumes seaweeds, with women comprising the majority of consumers who have done so since childhood (68% female vs. 32% male). These consumers were predominantly married (79%), within the 21–40 age group (53%), with families of 5–7 members (43%), practicing Islam (97%), and belonging to the Sama tribe (71%). A significant portion (48%) had resided in the area for 21–30 years, attained elementary to high school education (66%), and had a monthly income ranging from 1000 to 10,000 Philippine pesos (72%). Seaweed consumption was a family-wide practice (88%), including children, who typically started around 4–8 years old (61%), driven by perceived nutritional benefits (43%), preferred flavor (80%), affordability (19%), ease of preparation (33%), and cultural integration (23%). The primary edible seaweeds identified were Kappaphycus alvarezii (63%), K. striatus (58%), Kappaphycus spp. (47%), Eucheuma denticulatum (57%), Caulerpa lentillifera (64%), Caulerpa spp. (51%), C. cf. macrodisca ecad corynephora (45%), C. racemosa (30%), and Solieria robusta (49%), with less frequent consumption of K. malesianus (8%), Chaetomorpha crassa (3%), Gracilaria spp. (0.72%), and Hydroclathrus clathratus (0.36%). Specific plant parts were preferred for certain species, and preparation predominantly involved raw (75%) or cooked (77%) salads with spices, primarily prepared by mothers (72%). Consumers generally avoided seaweeds showing signs of ice-ice disease (95%), pale coloration (91%), or epiphyte infestation (84%). Consumption frequency was typically 1–3 times per week (45%), with knowledge largely passed down through generations (95%). Seaweed salads were primarily consumed as a viand (92%) at home (97%), with locals perceiving seaweed consumption as contributing to a healthy diet (40%) and overall well-being [e.g., aiding hunger (76%), improving digestion (20%), preventing obesity (14%), and aiding brain development (3%)]. The study’s findings emphasize the significant yet often overlooked role of seaweeds in the food systems and cultural heritage of Tawi-Tawi’s coastal communities. Future efforts should prioritize the sustainable management of wild resources, explore the cultivation of diverse edible species, and enhance nutritional awareness. Further research into traditional seaweed knowledge holds broader value. Full article

The microalgal defense strategies for different white light intensities (70–700 μmol m⁻² s⁻¹) were investigated in isolates from unexplored habitats, focusing on photosynthetic performance. Chlorella sorokiniana strain F4 from a Mediterranean inland swamp and two strains related to Pectinodesmus pectinatus (PEC) and Ettlia pseudoalveolaris (ETI) from an Ecuadorian highland lake were exposed to light over 18 h. The results showed that PSII photochemical efficiency was affected with increasing light due to photoinhibition or photodamage. F4 showed a low threshold of saturation light intensity, after which NPQ was compromised and total antioxidant levels were increased, leading to a reduction in its PSII photochemistry performance. F4 exhibited limited capacity for antennae reorganization in response to light stress. ETI and PEC differed in their photophysiological responses, although they came from the same habitat. ETI maintained high Chlb to Chla (i.e., large antennae), exhibited sustained energy dissipation, and preserved a high antioxidant pool (i.e., mycosporine-like amino acids) in all lights. Differently, in PEC, NPQ, antennae rearrangement, and reactive oxygen species scavenger pool were induced in a light-dependent manner. This study revealed the complex relationship between light parameters and microalgal physiology affected by environmental constraint adaptation and phylogenetic diversity. Full article

This study examines the influence of light wavelengths on the growth dynamics of five algal genera (Chlorella sp., Volvox sp., Gloeocapsa sp., Microspora sp., and Mougeotia sp.) in freshwater systems, using machine learning to optimize growth models. Natural light yielded the highest algal proliferation, increasing the total count from 90 to 1390 cells/mL in 30 days. Filtered wavelengths showed that blue light most effective (840 cells/mL), followed by red (490 cells/mL) and yellow (200 cells/mL), while green light minimally impacted growth (160 cells/mL). Genera-specific responses revealed that Gloeocapsa sp. and Mougeotia sp. thrived the most under blue light (240 and 750 cells/mL, respectively), with red and blue wavelengths generally enhancing growth across genera. Machine learning models achieved high accuracy (R² > 0.96 for total growth and R² > 0.8 for genera-specific and wavelength-based models), refining growth kinetics. These results suggest that spectral manipulation limiting blue/red wavelengths in water treatment to curb blooms while leveraging natural light for biofuel cultivation could optimize algal management. The integration of empirical data with machine learning offers a robust framework for predictive modeling in algal research and industrial applications. Full article

Macroalgal extracts are widely recognised as biostimulants that enhance crop productivity and plant growth under both optimal and stressful conditions. They offer a sustainable approach to mitigating the adverse effects of abiotic stress on crop development. This study investigates the efficacy of macroalgal-based fertilisers in enhancing tomato (Solanum lycopersicum L.) growth, yield, and fruit quality, as sustainable alternatives to chemical fertilisers. Different seaweed species (Sargassum muticum, Ulva ohnoi, Furcellaria lumbricalis, Ascophyllum nodosum, and a commercial A. nodosum extract) were evaluated as foliar treatments. The results showed that while the leaf fresh weight and chlorophyll content were not significantly affected, the fruit morphology and biochemical composition exhibited notable variations. Sargassum muticum-treated fruits displayed the highest °Brix (6.57), indicating superior sugar accumulation, while Ulva ohnoi maintained near-neutral pH levels (avg. 3.94), suggesting balanced acidity. Ascophyllum nodosum extracts induced the highest proline concentrations (peak: 63.77 µmol/g), but also caused extreme acidity (pH 1.39–2.58). Furcellaria lumbricalis enhanced the fruit size (axial length up to 41.4 mm), but reduced the pH sharply (1.69–2.13). The commercial product underperformed in regard to sugar content and flavour complexity. The integrative analysis revealed species-specific flavour profiles: Sargassum yielded sweet, mildly acidic fruits; Ascophyllum produced intensely aromatic, acidic tomatoes; and Ulva resulted in bland flavours. These findings underscore the importance of algal species and extraction methods in tailoring biofertilisers for target fruit qualities. This study advocates for the use of macroalgal fertilisers in sustainable agriculture, but highlights the need for optimised formulations to balance crop yield, taste, and stress adaptation. Full article

Microalgae are photosynthetic organisms with rapid growth and high biochemical diversity, capable of thriving in a variety of environments. Among them, dinoflagellates, particularly symbiotic species like Durusdinium glynnii, have gained attention due to their potential for biotechnological applications, especially in the production of valuable fatty acids. However, the delicate cultivation of dinoflagellates remains a challenge due to their sensitivity to shear stress and complex morphology. In this study, we evaluated the influence of inoculum percentage (10%, 25%, and 50%) on the growth performance and fatty acid profile of D. glynnii during a scale-up process from test tubes to a pilot-scale photobioreactor. Higher inoculum concentrations (50%) promoted faster acclimatization, higher specific growth rates (µ_max), and greater final biomass densities, optimizing the cultivation process. Meanwhile, lower inoculum concentrations (10%) favored the accumulation of polyunsaturated fatty acids, particularly DHA (C22:6n3), indicating a trade-off between biomass productivity and fatty acid biosynthesis. Overall, D. glynnii demonstrated robust adaptability, reinforcing its potential as a sustainable source of bioactive compounds. Further studies focusing on cellular and metabolic pathways are needed to better elucidate the mechanisms underlying lipid production and growth in this promising species. Full article

In most cases, the sizes of the daughter cells of diatoms follow the MacDonald–Pfitzer rule, whereby in many species all diatoms divide once in each generation. In contrast, there are division schemes in which the smaller or larger daughter cell is delayed in its division by one generation and therefore leads to Fibonacci growth. Several properties of diatoms, especially in chain-like colonies, that exhibit such delayed division can be modeled by Lindenmayer systems. These include, above all, the size and orientation of the diatoms. Certain sequences of properties, such as the differences in size indices of neighboring diatoms, are aperiodic and represent self-similar fractal structures. For the division schemes studied, explicit solutions can be found for the number of diatoms of a certain size in each generation. For the experimental differentiation of the division schemes in a diatom chain, in addition to the observation of the division processes over several generations, methods are available that only require the analysis of the structure of a sufficiently large sample. This includes the investigation of the differences in the sizes of neighboring diatoms, the orientations of the diatoms and the frequencies of size indices in a culture. These methods provide a toolbox for investigating diatom properties, applicable to the division models described. Additionally, a mathematical framework is presented that has the potential to be transferable to other properties and other division schemes. Full article