Journal of Applied Phycology最新文献

Over recent years consumer preference has shifted towards natural-based products, prompting the food, cosmetic, and pharmaceutical industries to explore new natural sources. Algae, particularly seaweeds like Caulerpa racemosa, have emerged as promising candidates due to their nutritional richness and bioactive compounds. This review comprehensively examines the nutritional profile of C. racemosa, covering its carbohydrates, fibers, proteins, amino acids, minerals, lipids, vitamins, and pigments. The alga is rich in bioactive metabolites, including terpenoids, alkaloids, sterols, and other secondary metabolites, which contribute to its health-promoting properties. The potential health benefits of C. racemosa are extensive, including antihypertensive, anti-hyperlipidaemic, antibacterial, antimicrobial, anti-cancer, anti-diabetic, anti-hyperglycaemic, anti-inflammatory, and antioxidant activities. Special emphasis is placed on its antioxidant properties, detailing the total phenol content (TPC), total flavonoid content (TFC), and the overall antioxidant capacity. Additionally, the tyrosinase inhibitory activity of C. racemosa suggests its potential in cosmetic applications. Despite its promising health and industrial uses, the standardization of C. racemosa products remains a challenge due to variability in active compound concentrations. This review underscores the multifaceted benefits of C. racemosa, advocating for its broader utilization in health, nutrition, and cosmetics, highlighting the need for further in-depth studies to fully realize its potential.

The escalating concern over food insecurity, micronutrient deficiencies, and the environmental impacts associated with current dietary practices has intensified research into sustainable, nutrient-dense food alternatives. This study, through a comprehensive scoping review, assessed the potential of macroalgae as a component of sustainable diets, examining their nutritional profile, contaminant levels, and the socio-economic and psychological factors influencing their consumption. Utilizing three major electronic databases—Web of Science, Medline/PubMed, and Scopus—we reviewed original articles in English, Spanish, or Portuguese without time restrictions and supplemented these with grey literature. After thorough screening and exclusion, 32 out of 473 articles were deemed suitable for inclusion. Our findings highlight 39 unique species of edible macroalgae, underscoring their potential to enhance human diets with crucial nutrients such as proteins, vitamin B12, and omega-3 and omega-6 fatty acids. Despite the nutritional promise of macroalgae, concerns regarding the bioavailability of these nutrients and the health risks posed by contaminants such as heavy metals must be addressed. Furthermore, levels of education and food neophobia emerged as significant factors explaining algae consumption and avoidance. The remarkable diversity of edible macroalgae represents a substantial yet underutilized opportunity to promote more sustainable diets. Integration of additional evidence regarding food safety, nutrition, and sociocultural aspects of consumption is needed.

Fertilizer use in agriculture and aquaculture significantly contributes to nitrate-rich effluent discharge into aquatic environments. Porphyra's high surface area/volume enables efficient nutrient assimilation. This study aimed to identify a cost-effective, efficient artificial seawater medium for Porphyra linearis cultivation and determine the optimal nitrate concentration to enhance photosynthetic activity. Porphyra linearis was grown in three different salt media, with photosynthetic and biochemical parameters assessed, showing no differences. The nitrate experiment (7 days) using low-cost salt and varied concentration (0 to 6.5 mM) revealed optimal nitrate uptake at 3 and 5 mM, while 6.5 mM indicated saturation/toxicity. The phycobiliproteins contents did not increase compared to the 0 mM, but exhibited greater functionality, as evidenced by the enhanced photosynthetic parameters. Chlorophyll a peaked in 3 mM, whereas lutein and β-carotene peaked in 0 and 3 mM. The thalli turned greenish and appeared to have degraded branches under 0 mM. Growth rate was the same under all nitrate concentration and higher than under 0 mM. The presence of nitrate increased ETR_{in situ} and ETR_max, whereas the absence decreased the range between optimal irradiance for photoinhibition (Eopt_ETR) and saturated irradiance for photosynthesis (Ek_ETR) and between saturated irradiance for non-photochemical quenching (Ek_NPQ) and Ek_ETR, suggesting that under more nitrate available the algae dissipate less energy. P. linearis showed a wide range of nitrate use without variation in pigment composition in contrast to photosynthetic capacity. The 1.5 and 3 mM in cultivation significantly enhance the photosynthetic response of P. linearis, supporting their potential application in IMTA and bioremediation.

Due to global food demand and need to protect the environment, improving crop productivity while reducing agrochemical use has become crucial. Microalgae offer a potential solution as they exhibit biostimulant and biofertilizer effects, improving both crop and soil quality. This study aimed to assess the impact of suspensions of freeze-dried Chlorella vulgaris (UTEX 265), Scenedesmus obliquus (UTEX 393), and Haematococcus pluvialis (UTEX 2505) biomass in distilled water on lettuce (Lactuca sativa L.) germination and development. Different microalgae treatments, individually and mixtures, were applied. The study evaluated various plant growth parameters and the concentration of nutritional constituents, including reducing sugars, total polyphenols, antioxidant capacity, and chlorophyll a. In the first stage (germination), microalgae treatments (C. vulgaris 2 g (CV2),; C vulgaris 0.66 g, S. obliquus 0.66 g and H. pluvialis 0.7 g (CV0.7:SO0.7:HP0.7) and C. vulgaris 1.5 g and S. obliquus 1.5 g (CV1.5:SO1.5) increased L. sativa seed germination rate and the number of germinated seeds. Significant changes were observed in growth-related variables such as height (CV0.7:SO9.7:HP0.7), stem diameter (C. vulgaris 3 g (CV3)), root length (S. obliquus 3 g (SO3)), and leaf area (CV1.5:SO1.5). In the second stage (plant development), microalgae treatments significantly increased dry weight from 2.71% (CV1.5:SO1.5) to 48.52% (SO3), reduced sugars from 3.20% (CV3) to 59.05% (CV1.5:SO1.5), total polyphenols from 7.99% (CV3) to 40.15% (CV1.5:SO1.5), antioxidant capacity from 0.77% (CV0.7:SO9.7:HP0.7) to 17.40% (CV1:HP1), and chlorophyll a from 23.01% (CV1.5:SO1.5) (p ≤ 0.05). C. vulgaris and S. obliquus in blending were identified as the main microalgae promoting positive effects on L. sativa development. This study confirms that microalgae, particularly C. vulgaris and S. obliquus, can enhance crop quality, specifically in L. sativa . These findings demonstrate the potential of microalgae as biostimulants, supporting their application to improve crop productivity and emphasizing their role in sustainable agriculture.

In many fields of biotechnology, pure microalgae cultures isolated from mixed cultures that exist in nature are needed as raw material sources for the production of high-quality products such as nutraceuticals, cosmetics and biofuels. Regarding the isolation of microalgae, microfluidic systems have gained popularity in recent years due to their low energy and chemical requirements for rapid and effective separation. In this study, optimum flow rates were determined using spiral microfluidics for the separation of microalgae from bacteria, followed by the cultivation of separated microalgae. Then the microalgae obtained in the green phase were subjected to nutrient stress to induce carotenoid production. Carotenoids were extracted after 30-day cultivation, and characterization analyses were performed. Subsequently, the SuperPro Designer® software was used to determine the potential for large-scale carotenoid production from Chlorella minutissima. The experiments showed that the fabricated microfluidic system achieved a separation yield and purity of 84.9% and 93.8%, respectively. Furthermore, a 2.5-fold increase in growth rate and carbohydrate and an approximately 1.3-fold increase in protein, lipid, and pigment contents were observed in the post-chip culture. Additionally, a 170% increase in carotenoids was observed within 20 days after induction with nutrient stress. Also, it was shown that microalgal carotenoids could be produced in large scale from C. minutissima by recultivating post-chip microalgae and subjecting them to nutrient stress. This study considered multiple flow rates in microchannels designed to separate microalgae from bacteria and carotenoid production from sorted microalgae for the first time.

An 8-week feeding trial was conducted to evaluate the impact of dietary Schizochytrium sp. on growth, fatty acid profile, non-specific immunity, and histopathology for Nile tilapia (Oreochromis niloticus) juveniles at initial individual weight of 0.88 ± 0.04 g. A control diet consisting of 40 % protein and 7 % lipid (D0, without Schizochytrium sp. supplementation) was used, along with five Schizochytrium sp. supplemented diets formulated at doses of 5 (D1), 10 (D2), 15 (D3), 20 (D4) and 25 g kg⁻¹ (D5), respectively. Each diet was randomly assigned to three replicate aquaria, each stocked with 50 uniform size and weight fish. At the end of the feeding trial it was found that the inclusion of dietary Schizochytrium sp. significantly enhanced the WGR (weight gain rate) and SGR (specific growth rate) of fish, particularly in the D2 group which exhibited the lowest FCR (feed conversion rate) and highest PER (protein efficiency rate). The whole-body crude lipid content decreased with increasing the levels of dietary Schizochytrium sp., while serum levels of TG (triglycerides) and TC (total cholesterol) also decreased concurrently. The DHA content of fillet was significantly up-regulated with the increase of dietary Schizochytrium sp. (P < 0.05). The activities of ALP (alkaline phosphatase), AST (aspartate transaminase) and ALT (alanine transaminase) in serum were found to be lower in Schizochytrium sp. supplemented treatment compared to the control group, with the lowest value observed in D2 group (P < 0.05). There was a positive correlation between serum lysozyme activity and dietary Schizochytrium sp. levels (P < 0.05). The malonaldehyde content initially declined followed by an increase in response to elevated dietary levels of Schizochytrium sp. with comparatively lower levels observed in the D2 group compared to other experimental groups (P < 0.05). Furthermore, the results of liver and intestinal morphology analysis revealed that 1 g kg^-1 dietary Schizochytrium sp. supplementation could maintain hepatocyte integrity and increase villus height in the intestine. Conversely, excessive intake of Schizochytrium sp. (≥2 g kg^-1) led to nuclear migration and vacuolation in hepatocytes. In conclusion, these findings indicate that dietary Schizochytrium sp. can enhance feed utilization, non-specific immunity, antioxidant capacity, as well as liver and intestinal morphology, ultimately improving the nutritional value of fillets, but excessive supplementation may result in liver tissue lesions.

Benthic phototrophic communities play a crucial role in the functioning of shallow lake ecosystems. The complexity of benthic algal communities poses challenges for exploring their fine structures using traditional methods such as light microscopy. However, confocal laser scanning microscopy (CLSM) offers the potential for microscale-level structural investigation of phototrophic biofilms, thereby contributing to a deeper understanding of the structural and compositional changes within these communities. The primary objective of this study was to develop a relatively rapid, semi-automated, and freely available image processing method to facilitate the tracking of spatio-temporal alterations in intact biofilms. To evaluate our image processing method, we conducted an eight-week long outdoor mesocosm experiment, manipulating temperatures based on two global warming scenarios (assuming intermediate- and high degree of greenhouse gas emission), with increases of 3°C and 5°C, respectively, compared to the reference/unheated mesocosms. Eight limestone cubes were placed on the bottom of each mesocosm to provide 'natural' surfaces for phytobenthos colonization, which was subsequently analysed by confocal microscopy. We hypothesized that increasing water temperature might have a significant impact on the taxonomic composition of algal biofilms, particularly on the abundance of phototrophic prokaryotes and eukaryotes. The designed 'FIJI macro' efficiently analysed the recorded images, including single images, series of Z-stack images, and projection images. Our image processing method effectively discriminated photosynthetic prokaryotes and eukaryotes based on their pigment composition and proved suitable for the high-throughput analysis of structural and compositional changes in algal biofilms. Moreover, this study confirmed that climate-induced warming can lead to an increasing dominance of cyanobacteria in benthic phototrophic communities at the expense of eukaryotic algae.

The human population is steadily increasing and new alternative protein sources are necessary to secure food safety. There is a growing interest in macroalgae, or seaweed, as an alternative food source as they are rich in nutrients, minerals and carbohydrates. Among the diverse species of macroalga, Palmaria palmata, a red seaweed of growing interest due to its high protein content, represents a potential candidate for contributing to food security and animal feed. Novel methods are being investigated for extracting valuable components from seaweed, including protein. In this study, pulsed electric field (PEF) and enzymatic assisted extraction (EAE) were tested to investigate whether the methods, alone or in combination, were sufficient for protein extraction from P. palmata. The results show high extraction yields of dry matter consisting mostly of carbohydrates and ash when using EAE. The results point to a concentration of protein, including essential amino acids, in the pellet after extraction with a combination of PEF and EAE, or EAE alone. There is potential for the protein-rich pellet in animal feed. For the supernatant, there are potential uses within biostimulants.

In this study two types of marine algae: red algae (Callithamnion corymbosum – CC-RAB) and green algae (Ulva lactuca – UL-GAB), were used for the retention of Cu²⁺, Zn²⁺ and Co²⁺ ions from aqueous media, by biosorption. Both types of marine algae are abundant on the Romanian coast of the Black Sea and, since they have no uses, they represent a serious problem for the beach area. Therefore, their use as biosorbents for the recovery of some metal ions of strategic industrial importance (such as Cu²⁺, Zn²⁺ and Co²⁺ ions) may represent a way to valorise this biomass resource. In order to evaluate the biosorptive performances of the red algae biomass (CC-RAB) and green algae biomass (UL-GAB), batch experimental studies were carried out at different initial solution pH, biosorbent dose, initial metal ions concentration contact time and temperature. The optimal conditions (pH = 5.0; 2.0 g biosorbent L^-1, 3 h, 25 ±1 °C) were then used to obtain kinetic curves and biosorption isotherms, which were modelled. The pseudo-second order kinetic model best fits the kinetic data, while the biosorption isotherms are described by the Langmuir model, for all studied metal ions on both biosorbents. The maximum biosorption capacity depends on the nature of algae biosorbent, and follows the order: Cu²⁺ (81.25 mg g^-1) > Zn²⁺ (73.69 mg g^-1) > Co²⁺ (27.89 mg g^-1) in the case of CC-RAB, and Zn²⁺ (69.29 mg g^-1) > Cu²⁺ (43.47 mg g^-1) > Co²⁺ (26.15 mg g^-1) in the case of UL-GAB. The thermodynamic parameters (∆G⁰, ∆H⁰ and ∆S⁰) were also evaluated, and the obtained values indicate that all biosorption processes are spontaneous and endothermic. In addition, desorption of metal ions is quantitative in acid media, but the biosorption capacities decrease significantly after the first cycle of use. All these aspects have important environmental implications, and may provide benchmarks in the design of a strategy for the valorisation of this biomass resource.

Gracilaria cornea was exposed to different irradiance intensities (low, moderate, and high) and light qualities (white and white + blue) in experimental cultures. Photosynthetic physiology was measured through daily growth rate, maximum photosynthesis, maximum photochemical efficiency, pigment content (chlorophyll a, phycobiliproteins, carotenoids), and elemental content of carbon and nitrogen. Gracilaria cornea effectively acclimated to low irradiance conditions and displayed tolerance to moderate irradiance, whereas high irradiance resulted in the deterioration of thalli. A decrease in maximum photochemical efficiency and maximum photosynthesis rate under high irradiance conditions was observed. Pigment content decreased during the acclimation period at high irradiance levels but increased when blue light was added under moderate irradiance conditions. The antioxidant capacity decreased in thalli exposed to high irradiance conditions, whereas the addition of blue light increased antioxidant capacity. Overall, the combination of white and blue light stimulated the accumulation of all evaluated compounds in G. cornea. Interestingly, higher values for photosynthesis, pigments, and certain antioxidants were observed under low irradiance conditions. These findings enhance our understanding of the adaptation strategies employed by G. cornea, potentially leading to improvements in indoor cultivation and the control of chemical compound production for nutraceutical applications.