Journal of Applied Phycology最新文献

The global ocean is undergoing gradual acidification and eutrophication which may have significant impacts on macroalgal communities. However, little is known regarding the interactive effects of ocean acidification (OA) and nitrate on Ulva lactuca, a primary producer widely distributed in coastal waters. This study focuses on the possible interactive effects of OA and elevated nitrate levels on physiological parameters of U. lactuca. Higher nitrate levels may increase growth, photosynthesis, respiration, pigment synthesis, F_v/F_m and Effective Quantum Yield, whereas CO₂ enrichment may result in a reduction in photosynthesis, pigment content, F_v/F_m and Effective Quantum Yield. Higher nitrate levels increase NO₃^- uptake rate and nitrate reductase activity, which are further amplified by elevated CO₂ levels. However, the stimulation of high nitrate towards pigment synthesis and photosynthesis is negatively affected by elevated CO₂ levels. Our results suggest that U. lactuca could potentially increase its biomass in coastal eutrophic waters, and OA in the future is not expected to promote the growth of U. lactuca, but it can enhance its potential biofiltration to remove nitrate from coastal ecosystems.

Bisphenol A (BPA) is an emerging organic compound used in the production of epoxy resin, polycarbonate plastics and thermal paper. Following the restrictions on the use of bisphenol A, many substitutes have been produced as its replacement in several consumer products. The main task of this research was to examine the toxic effects of single bisphenol analogues and their mixtures against freshwater microalgae Chlorella vulgaris and Desmodesmus armatus. The findings suggest that bisphenol B, bisphenol C, bisphenol PH (EC₅₀ (14 day): 33.32-43.32 mg L^-1) and bisphenol B, bisphenol C, bisphenol FL, bisphenol PH (EC₅₀ (14 day): 30.49-64.54 mg L^-1) show strong toxic effects towards C. vulgaris and D. armatus, respectively. In turn, the research results indicate that the toxicity of a mixture of examined bisphenol analogs on both species of green algae is much higher (EC₅₀ (14 day): 24.55-32.68 mg L^-1) than the individual toxicity of each component of the mixture. Therefore, it can be concluded that mixtures lead to the occurrence of synergistic effects. The toxicity of the individual bisphenol analogues and their mixture by EC₅₀ (14 day) values in descending order, was as follows: mixture>bisphenol PH> bisphenol B> bisphenol C> bisphenol FL> bisphenol F> bisphenol E for C. vulgaris and bisphenol B> mixture> bisphenol FL> bisphenol C> bisphenol PH> bisphenol E> bisphenol F for D. armatus, respectively. Moreover, the present research expands current knowledge of the ecotoxicological risks of bisphenol analogues to aquatic organisms.

This study assessed the effectiveness of the treatment of tomato seeds with an aqueous extract of the dried biomass of the microalga Anabaena minutissima in protecting the plants from diseases caused by soilborne pathogens like Rhizoctonia solani and Pythium ultimum. The extract, obtained by an autoclave-assisted method at 100 °C, was rich in proteins and carbohydrates (56.6 and 26.9% of total solids). Preliminary tests were performed revealing: i) a moderate direct activity toward pathogen in vitro growth, with ± 9% stimulation/inhibition, depending on the pathogen; ii) a stimulatory/inhibitory activity toward seedling growth, depending on the dose; iii) no effect on the mycelial growth by root exudates of treated plantlets. Then, a greenhouse experiment was set up to test the response of tomato plants in substrates artificially inoculated with the single pathogens, after seed treatment with the extract at different doses (0, 2.5, 5, and 10 mg mL^-1). The treatment generally increased the percentage of standing plants and restored plant development up to the level of healthy controls. Moreover, the disease incidence and severity progressively reduced at increasing doses. Finally, the seed treatment significantly increased some markers of induced systemic resistance like endochitinase and glucanase activity, in hypocotyls of 14-day-old seedlings, compared to non-treated controls. Besides, the treatment increased epicotyls’ carotenoid and chlorophyll a and b content. Overall, these results demonstrate that seed priming with A. minutissima aqueous extract is a promising eco-friendly tool to ameliorate tomato plant responses towards soilborne pathogens, stimulating plant growth and activating induced resistance mechanisms.

Nano-filtered whey permeate (WP), a major by-product of dairy industry, is produced by membrane filtration of whey. The oleaginous microalga Nannochloropsis oceanica was successfully cultivated on WP without salinity and nutrient amendments. Growth, cell characteristics, and fatty acid profile of the cultures were analyzed using microscopy, flow cytometry, and GC analysis. WP was nitrogen limited, comprising primarily protein as a nitrogen source and only small amounts of free inorganic nitrogen (in the form of nitrate). Nannochloropsis oceanica (and associated bacteria) efficiently removed nitrate (100%), protein (87%), and phosphate (74%) from the whey permeate. Microscopic and flow cytometric analysis revealed diverse size distributions in whey permeate cultures, with significant cell aggregation attributed to low-salinity acclimatization and nitrogen limitation. Autofluorescence analysis revealed reduced photosynthetic activity in whey permeate-grown cells, possibly as a consequence of heightened mixotrophic activities on carbon source in the medium. Low nitrogen availability in whey permeate resulted in biomass with a fatty acid profile enriched in saturated fatty acids. Despite this, a considerable level of the omega-3 polyunsaturated fatty acid (in the form of eicosapentanoic acid or EPA) was detected at ca. 16% of total fatty acids. Whey permeate proved beneficial for the growth of N. oceanica and yielded high concentrations of eicosapentaenoic acid in the extracted lipids for potential applications in the feed/food industries.

Edible brown seaweeds of the genus Sargassum have the potential to be utilized as nutrient-rich food components yielding beneficial health effects upon consumption. This study aimed to characterise Sargassum crassifolium for its phytochemical content and antioxidant capacity followed by its utilization as a dry powder in wheat noodles as a flour replacement. Sargassum crassifolium dehydrated powder contained considerable amounts of total phenols (1.13±0.05 mg GAE g^-1 DW), flavonoids (21.07±0.79 mg RE g^-1 DW), fucoidan (2.9±0.48 mg g^-1 DW), fucoxanthin (0.963±0.00 µg g^-1 DW), carotenoids (1.88±0.002 µg g^-1 DW) and tannins (1.88±0.002 mg g^-1 DW), while displaying significant DPPH (2,2-diphenyl-picrylhydrazyl hydrate) radical scavenging activity (23.20±1.73%). The use of 2.5% S. crassifolium as a flour replacement enhanced the sensory properties, nutrient composition and phytochemical content of the noodles. The DPPH radical scavenging activity of 2.5% S. crassifolium noodles (19.88±1.56%) in the cooked form was significantly higher than that of the control noodles containing no seaweed (13.29±2.02%). The results of this study revealed that S. crassifolium can be successfully incorporated in noodles to yield acceptable products that have improved nutrient content and potential functionality.

Microalgae are increasingly recognized as a valuable resource for bolstering sustainability in agriculture. However, current research and patents primarily focus on Chlorella spp., Scenedesmus spp., and Spirulina spp., thus leaving the vast diversity of microalgae relatively unexplored for agricultural applications. Euglena gracilis (Euglenophyta) is a microalga renowned for its resilience to diverse environmental stressors and capability to produce a variety of bioactive metabolites. This study investigated the potential of cultivating E. gracilis in piggery wastewater for nutrient recycling and as a source of beneficial biomolecules, particularly for biostimulant use. Utilizing raw wastewater diluted to 25% (P25) and pre-treated wastewater with photo-Fenton (PF), the research found that E. gracilis exhibited elevated cell density, biomass concentration, and overall cell health in both wastewaters compared to a synthetic medium (BG11-NPK). This was due to its efficient removal of nutrients, especially ammoniacal-nitrogen and phosphate, resulting in a biomass rich in polyunsaturated fatty acids, amino acids, and paramylon content. The whole-cell biomass significantly enhanced the germination index of lettuce and tomato seeds compared to the water control. Additionally, it promoted cell expansion and root formation in cucumber cotyledons, exhibiting similarities to phytohormones such as gibberellin, cytokinin, and auxin. Furthermore, it is suggested that E. gracilis biomass contains molecules related to resistance to environmental stresses, particularly in tomatoes, given the enhancement in the seedling vigor index. E. gracilis exhibited remarkable adaptability to piggery wastewater, recycling nutrients and yielding biomass rich in bioactive molecules with potential as plant biostimulants. These findings significantly contribute to understanding E. gracilis's potential applications in agriculture and developing a circular bioeconomy.

Ultrasound-assisted extraction and enzyme-assisted extraction are two methods that can be employed to recover valuable compounds from seaweeds at milder operating conditions than conventional chemical extraction methods. The aim of the study was to determine whether pH, enzyme addition and extraction temperature significantly impacted extraction of alginate from Ecklonia maxima in the presence of ultrasonication and to model extraction kinetics. Firstly, a 2³ factorial experimental design was employed at constant sonication rate, with pH (8 and 10), temperature (50 and 60 °C), and enzyme-to-substrate ratio (E:S 0 and 1 %) as the independent variables. Secondly, extraction kinetics of alginate were investigated at different extraction conditions, through fitting of the Peleg and Power models. Highest extraction for alginate was achieved at pH 10, 60 °C, E:S = 0 % within the first 60 min of extraction. The addition of enzyme improved solubilised dry matter content, but it had a less clear impact on the alginate yield. Both the Peleg (R² = 0.893 – 0.997) and Power function (R² = 0.861 – 0.987) models provided good fit to the experimental data and can used to describe extraction kinetics of alginate during combined ultrasound-enzymatic assisted extraction.

The traditional and local edible brown algae Ecklonia cava subspp. kurome (EK) and stolonifera (ES) are rich in minerals, phlorotannins (brown algal polyphenols), and water-soluble dietary fibres (alginate, laminaran, and fucoidans). These dried powders increase not only alginate- and laminaran-degrading Bacteroides acidifaciens- and B. intestinalis-like bacteria but also Faecalibaculum. To elucidate the effect of EK and ES ingredients, other than dietary fibres, on gut microbiota, 100 mL of ethanolic/aqueous extract solutions (EK-S, ES-S; final solvent was distilled water) were prepared from 100 g of dried samples. EK-S and ES-S contained total phenolic contents of 160 and 120 μmol phloroglucinol equivalent mL^-1, respectively. A diet containing 5% (v/w) EK-S or ES-S was fed to ICR mice for 14 days. Amplicon sequencing of the 16S rDNA (V4) gene revealed that EK-S and ES-S increased Faecalibaculum abundance 2-fold and more, and this was the predominant genus (37–38%) in mice. However, the abundances of B. acidifaciens- and B. intestinalis-like bacteria did not increase. Akkermansia muciniphila-like bacteria were higher in EK-S-fed mice. Faecalibaculum and Akkermansia are regarded as desirable gut commensals correlated with anti-inflammatory and immunomodulatory effects on the host’s health. These results suggest that phlorotannins have beneficial functional effects on indigenous gut bacteria responsible for host health.

This methodology paper introduces an illuminated culture flask-based 3D-printed bioreactor system (FlaskLED) based on Arduino, Grove ecosystem and LED sticks. The Arduino microcontroller allows extensibility and future upgrades via programming and other modifications. We provide the 3D printer files, video presentation of assembly instructions and a detailed description of the INO code and wiring scheme. The INO code presented can be used to produce different light colors and patterns of varying intensity and durations (intermittent/flashing/pulsing light). The system was validated by examining the toxicity of Au³⁺ ions on Phaeodactylum tricornutum growth. The capabilities of the system offer unique applications for laboratory and industrial research. Our aim is to provide a low-cost and open-source tool to promote and improve cultivation of microalgae and other photosynthetic organisms under different laboratory and experimental setups.

The deficiency in the worldwide protein provision from marine capture fisheries has led the Malaysian government to reevaluate its aquaculture approach, prioritising three commodities: seaweed, fish, and marine shrimp. However, comprehensive documentation of the performance of the Malaysian aquaculture sector, particularly in seaweed production, is lacking. Caulerpa (Chlorophyta), a seaweed genus abundantly available in Malaysia, holds the potential to emerge as a primary alternative food source in the future. This paper offers an overview of Caulerpa aquaculture, specifically focusing on C. lentillifera and C. racemosa, covering aspects such as taxonomy, phytomorphology, geographical distribution and habitat, cultivation system, chemical composition, pharmacological properties, and future prospects for sustainable aquaculture. Although the cultivation system has been implemented on a small scale in various districts in Malaysia, it is anticipated to escalate production and productivity due to the substantial demand for Caulerpa spp. both domestically and globally. The cultivation of Caulerpa spp. in Malaysia, in alignment with the National Agrofood Policy 2021–2030 (NAP 2.0), signals a trajectory toward enhancing the nation's food security in aquaculture and meeting the economic requirements for seaweed production.