Search Results (32)

Background/Objectives: Chlorella pyrenoidosa polysaccharides (CPPs) exhibit digestion-resistant properties, with their bioactivity largely driven by gut microbiota metabolism. However, the fermentation characteristics of CPPs within the intestinal tract remain to be fully elucidated. Elucidating the utilization and metabolic processes of CPPs with respect to the gut microbiota aids in understanding the potential mechanisms underlying the biological activity of these polysaccharides. Methods: This work fractionated CPPs into a neutral polysaccharide fraction (CPP-1) and an acidic polysaccharide fraction (CPP-2), followed by the characterization of their structure, physicochemical properties, and in vitro fermentation characteristics. Results: The results demonstrated that both CPP-1 and CPP-2 were non-starch heteropolysaccharides linked primarily by α-glycosidic bonds and lacking a triple helix structure. Both samples exhibited exceptional thermal stability, high water solubility, and low viscosity properties. CPP-2 selectively promoted Enterocloster, whereas CPP-1 significantly enriched Bacteroides and Bifidobacterium in gut microbiota. This differential regulation may be attributable to structural variations between the polysaccharides. Functional predictions indicated that CPP-1 enhances intestinal barrier integrity and immune homeostasis, whereas CPP-2 has anti-inflammatory activity. CPP-1 and CPP-2 interventions significantly upregulated the levels of health-promoting metabolites, including nicotinamide adenine dinucleotide, putrescine, and 3′-adenosine monophosphate. CPP-1 predominantly modulated amino acid metabolic pathways, while CPP-2 could effectively regulate purine, pyrimidine, amino acid, and butanoate metabolic pathways. Conclusions: This work identifies CPPs (CPP-1 and CPP-2) as novel modulators of gut homeostasis and host metabolism through microbiota–metabolite axis remodeling, supporting their prebiotic potential for functional food innovation. Full article

The current interest in microalgal biomass does not subside but continues to intensify due to the emergence of new trends in the use of this bioresource in various biotechnological and environmental processes. The rather slow growth rate of phototrophs compared to other microorganisms limits more active application of the biomass for various purposes. Stimulation of the Quorum Sensing formation in the cells due to the appearance of their own quorum molecules or those produced by other co-cultured microorganisms in the medium is one of the efficient approaches for overcoming this limitation. This review discusses the immobilization or co-immobilization of phototrophic cells with other microorganisms as an effective way to maintain accumulation of the target biomass for long-term period at improved rates. The 40% increase in the use of co-immobilized phototrophs for biomass obtaining and its use in wastewater treatment has been observed over the past five years. The level of investigations of co-immobilized microalgae cells is four times higher than that of the immobilized single cultures. Among the main trends in the new investigations of immobilized forms of microalgae, the predominant application of Chlorella genus cells in immobilized samples of individual cultures and the involvement of diatom microalgae and cyanobacteria, in addition to Chlorella cells, in co-immobilization with other microorganisms, was ascertained. The most significant increase in the rate of microalgal biomass accumulation uncovered in cases of co-immobilization of microalgae with bacteria. In several cases, in the presence of bacteria, co-immobilization has led to the emergence of new characteristics in microalgal cells (increased synthesis of pigments, polysaccharides, biofilm formation, etc.), which opens new directions for their further practical use as biopesticides, components of packaging and building materials, etc. Full article

The environmental problems brought about by factory-based aquaculture have become increasingly prominent. Reducing nitrogen and phosphorus concentrations in tailwater has become the key to tailwater management. In order to assess the potential of microalgae in removing nitrogen and phosphorus ions from aquaculture wastewater, four microalgae species, i.e., Chlorella sp., Dicrateria zhanjiangensis, Nitzschia closterium minutissima, and Platymonas subcordiformis, were used in this study, and their growth and nitrogen and phosphorus removal rates in four nutrient concentrations of simulated aquaculture wastewater were systematically evaluated. After 15 days of cultivation, the cell counts of all four types of microalgae increased. Three species, i.e., Chlorella sp., N. closterium minutissima, and P. subcordiformis, grew best in high PO₄³⁻ and low NH₄⁺ medium, whereas D. zhanjiangensis possessed best growth in low PO₄³⁻ and high NH₄⁺ medium. The removal rate of PO₄³⁻, NH₄⁺, NO₃⁻, and NO₂⁻ by four microalgae species exceeded 82.64%, 89.06%, 59.27%, and 42.15%, respectively, even though the four microalgae had different performance in the removal of nitrogen and phosphorus. All microalgae in the low-phosphorus groups removed PO₄³⁻ at significantly lower rates than those in the high–phosphorus groups, while high NH₄⁺ removal rates were observed in all four microalgae groups. Moreover, in phosphorus-limited conditions, four microalgae exhibit lower removal rates of NO₃⁻ when nitrogen content was high. The chlorophyll a contents of microalgae in four culture media strictly corresponded to their final cell densities. P. subcordiformis exhibited the highest intracellular polysaccharide accumulation in high PO₄³⁻ and low NH₄⁺ type medium, whereas D. zhanjiangensis demonstrated the strongest protein synthesis capacity in high PO₄³⁻ and low NH₄⁺ medium. The activities of acid phosphatase in all microalgae were higher under phosphorus–deficient conditions than phosphorus-sufficient conditions. Our results might provide useful references for microalgae selection in the treatment of different aquaculture wastewater conditions. Full article

The use of Auxenochlorella pyrenoidosa (formerly Chlorella pyrenoidosa) and its intracellular substances (ISs) to promote biofloc development has been extensively studied. To identify the key components of the ISs of A. pyrenoidosa that drive biofloc formation, algal-extracted polysaccharides (AEPSs) and algal-extracted proteins (AEPTs) were isolated from the ISs. In this study, we established four groups: ISs, AEPSs, AEPTs, and tap water (TW, control), to investigate the effects of AEPSs and AEPTs on biofloc formation dynamics, water quality parameters, and microbial community composition. The results indicated no significant differences were observed between the ISs and AEPSs groups during the cultivation period. AEPSs significantly enhanced flocculation efficiency, achieving a final floc volume of 60 mL/L. This enhancement was attributed to the selective promotion of floc-forming microbial taxa, such as Comamonas, which can secrete procoagulants like EPS, and Pseudomonas and Enterobacter, which have denitrification capabilities. Water quality monitoring revealed that both AEPSs and AEPTs achieved nitrogen removal efficiencies exceeding 50% in the biofloc system, with AEPSs outperforming AEPTs. This is closely related to the fact that the microorganisms with increased flocculation contain numerous nitrifying and denitrifying bacteria. So, the intracellular polysaccharides were the key component of the ISs of A. pyrenoidosa that drive biofloc formation. These findings provide critical insights into the functional roles of algal-derived macromolecules in biofloc dynamics and their potential applications in wastewater treatment. Full article

The immunomodulatory polysaccharide CPP-3a, purified from Chlorella pyrenoidosa, was investigated for its effects on RAW264.7 macrophages and underlying mechanisms, revealing that CPP-3a significantly enhanced phagocytic capacity and nitric oxide production while upregulating pro-inflammatory cytokines TNF-α and IL-6 and elevating the co-stimulatory molecule CD86, collectively driving robust M1 polarization. Mechanistically, TLR4-, TLR2-specific inhibitors, and TLR4-knockout cells confirmed TLR4 as the primary receptor for CPP-3a, with TLR2 playing a secondary role in cytokine modulation. CPP-3a activated NF-κB and p38 MAPK signaling pathways via the MyD88-dependent pathway, evidenced by phosphorylation of NF-κB/p65 with its nuclear translocation and increased phosphorylation of p38 MAPK, with these signaling activations further validated by specific pathway inhibitors that abolished M1 polarization phenotypes. Collectively, CPP-3a emerges as a potent TLR4-targeted immunomodulator with adjuvant potential for inflammatory and infectious diseases. Full article

The capture and conversion of industrial off-gases into valuable biomass using microalgae represents a promising strategy for CO₂ mitigation and sustainable production of biofuels and biochemicals. In this study, fifteen (15) microalgal strains were screened and evaluated for their growth performance and the accumulation of macromolecules like polysaccharides and lipids under CO₂-enriched conditions, simulating the off-gas composition of an operational 2G biorefinery producing bioethanol from wastes. It was found that Stichococcus sp. exhibited the highest polysaccharides accumulation (33% w/w) in biomass, while Chlorella vulgaris demonstrated superior lipids content (34% w/w). Both strains (coded as wild-AUTH) displayed robust growth, each achieving biomass concentrations of 1.5 g/L of Dry Cell Weight (DCW), while maintaining tolerance to the gas feedstock. The protein contents of the strains further support their potential integration into a 3G biorefinery framework, where advanced biofuels could be one of multiple valorization pathways. These findings underline the feasibility of using microalgae as a retrofitting solution for bioethanol and other bioenergy plants, enhancing CO₂ capture while enabling biofuel production. The top-performing species provide a basis for optimizing bioprocess parameters and scaling up the cultivation in industrial photobioreactors (PBRs) to improve productivity and commercial applicability. Full article

Microalgae have emerged as a valuable source of essential nutrients and bioactive compounds, such as proteins, polyphenols, and polysaccharides, which are critical for overall health. Recent research has demonstrated the therapeutic potential of microalgae in addressing a variety of health conditions, including inflammation, oxidative stress, Type 2 diabetes mellitus (T2DM), and neurological disorders. The aim of this paper is to investigate the chemical composition, nutritional value, and biological properties of microalgae. Relevant information was gathered through a comprehensive search of scientific databases, including PubMed, Science Direct, Google Scholar, and the Cochrane Library. Key microalgal strains such as Spirulina platensis, Chlorella vulgaris, Haematococcus pluvialis, and Dunaliella salina have shown notable health-promoting properties. For instance, Spirulina platensis is rich in proteins, vitamins, and polyunsaturated fatty acids, while Chlorella vulgaris offers significant levels of chlorophyll and carotenoids. Haematococcus pluvialis is recognized for its high astaxanthin content and Dunaliella salina for its beta-carotene content. These microalgae strains have demonstrated beneficial effects in managing type 2 diabetes mellitus, alleviating oxidative stress, and offering neuroprotective potential. This paper provides an overview of microalgae’s nutritional composition, their medicinal properties, and their promising role in treating chronic diseases, with a particular focus on their applications in antidiabetic and neuroprotective therapies. Full article

Four types of algae—Porphyra umbilicalis, Undaria pinnatifida, Cystoseira barbata, and Chlorella sp.—were used to obtain crude bioproducts enriched in polysaccharides (four bioproducts) and to create formulations enriched with gold cations (four bioproducts). The bioproducts obtained through aqueous extraction from Cystoseira barbata exhibited significant antioxidant activities and a total polyphenol content of (714.17 ± 1.26) mg GAE/L. In the bioproducts derived from the aqueous extract of Porphyra umbilicalis and Undaria pinnatifida, combined with gold ions, gold nanoparticles with sizes of less than 34 nm were formed. In vitro tests performed on the Caco-2 tumour cell line with each of the eight bioproducts, after 24 h of exposure, showed that the crude bioproducts containing polysaccharides derived from Porphyra umbilicalis, Undaria pinnatifida, and Chlorella sp. exhibited cytotoxicity against the Caco-2 cell line. In the case of the HepG2 cell line, after 24 h of exposure, the tests indicated that only the crude polysaccharides derived from Cystoseira barbata exhibited cytotoxic effects. These results indicate the protective effect of the algal polysaccharides against the tumourigenesis processes that may occur in the human digestive system. Regarding the bioproducts containing gold, no cytotoxic effect was observed. However, in the case of the two algal bioproducts containing gold nanoparticles with a size of less than 34 nm, they may represent potential raw materials for electrochemical sensors. Full article

The environmental treatment of endocrine-disrupting compounds (EDCs) has attracted significant attention. Nonylphenol (NP), a highly toxic EDC with widespread distribution, presents an urgent challenge requiring effective removal strategies. Although microalgae-based treatments offer environmentally friendly and cost-effective solutions, the high toxicity level of NP impedes this process. Analysis was conducted on cell biomass, cell morphology, extracellular polymeric substances (EPSs), and the degradation of nonylphenol in Chlorella pyrenoidosa treated with nonylphenol and glucose. Glucose restored the algal biomass to 2.23 times its original level, reduced cellular damage, and maintained normal physiological activities. Glucose also stimulated algal metabolism and promoted the secretion of EPSs. The polysaccharide content of soluble EPSs (S-EPSs) increased by 32.7%, whereas that of the bound EPSs (B-EPSs) increased by 55.5%. The three-dimensional excitation–emission matrix fluorescence spectroscopy of B-EPS indicated that glucose enhanced tryptophan secretion. Glucose showed great potential as a biostimulant to enhance NP bioremediation efficiency in aquatic ecosystems. This finding indicates that the nonylphenol remediation of wastewater can be integrated with microalgal biomass recovery, creating opportunities for revenue generation. Full article

Atopic dermatitis (AD) is a chronic, inflammatory skin condition characterized by severe pruritus and recurrent flare-ups, significantly impacting patients’ quality of life. Current treatments, such as corticosteroids and immunomodulators, often provide symptomatic relief but can lead to adverse effects with prolonged use. Seaweed, a sustainable and nutrient-dense resource, has emerged as a promising alternative due to its rich bioactive compounds—polysaccharides, phlorotannins, polyphenols, and chlorophyll—that offer anti-inflammatory, antioxidant, and immunomodulatory properties. This review explores the therapeutic potential of brown, red, and green algae in alleviating AD symptoms, highlighting the effects of specific species, including Undaria pinnatifida, Laminaria japonica, Chlorella vulgaris, and Sargassum horneri. These seaweeds modulate immune responses, reduce epidermal thickness, and restore skin barrier function, presenting a novel, safe, and effective approach to AD management. Further clinical studies are needed to confirm their efficacy and establish dosing strategies, paving the way for seaweed-derived therapies as natural alternatives in AD treatment. Full article

The quest for cleaner and sustainable energy sources is crucial, considering the current scenario of a steep rise in energy consumption and the fuel crisis, exacerbated by diminishing fossil fuel reserves and rising pollutants. In particular, the bioaccumulation of hazardous substances like trivalent chromium has not only disrupted the fragile equilibrium of the ecological system but also poses significant health hazards to humans. Microalgae emerged as a promising solution for achieving sustainability due to their ability to remediate contaminants and produce greener alternatives such as biofuels. This integrated approach provides an ambitious strategy to address global concerns pertaining to economic stability, environmental degradation, and the energy crisis. This study investigates the intricate defense mechanisms deployed by freshwater microalgae Chlorella minutissima in response to Cr (III) toxicity. The microalga achieved an impressive 92% removal efficiency with an IC₅₀ value of 200 ppm, illustrating its extraordinary resilience towards chromium-induced stress. Furthermore, this research embarked on thorough explorations encompassing morphological, pigment-centric, and biochemical analyses, aimed at revealing the adaptive strategies associated with Cr (III) resilience, as well as the dynamics of carbon pool flow that contribute to enhanced lipid and extracellular polysaccharide (EPS) synthesis. The FAME profile of the biodiesel produced complies with the benchmark established by American and European fuel regulations, emphasizing its suitability as a high-quality vehicular fuel. Elevated levels of ROS, TBARS, and osmolytes (such as glycine-betaine), along with the increased activity of antioxidant enzymes (CAT, GR, and SOD), reveal the activation of robust defense mechanisms against oxidative stress caused by Cr (III). The finding of this investigation presents an effective framework for an algal-based biorefinery approach, integrating pollutant detoxification with the generation of vehicular-quality biodiesel and additional value-added compounds vital for achieving sustainability under the concept of a circular economy. Full article

This review presents the chemical composition, bioactive properties, and diverse applications of Chlorella vulgaris, a green microalga widely recognized for its exceptional nutritional value and therapeutic potential. The study emphasizes the presence of key nutrients, including high-quality proteins, essential vitamins, minerals, and an array of bioactive compounds such as carotenoids, chlorophyll, and polysaccharides. These compounds have been shown to exhibit a wide spectrum of biological activities, including potent antioxidant, anti-inflammatory, immunomodulatory, antiviral, anticancer, antidiabetic, lipid-lowering, and detoxifying effects. The review explores the multifaceted applications of C. vulgaris in various sectors, including its growing role as a functional food ingredient, a nutraceutical supplement in animal feed, and a promising therapeutic agent for combatting chronic diseases. This paper also highlights its potential for enhancing immune responses, mitigating oxidative stress, promoting detoxification of heavy metals, and improving overall health outcomes. However, current limitations in clinical evidence surrounding its medicinal efficacy present challenges that need to be addressed. Furthermore, significant obstacles remain in scaling up C. vulgaris production, including optimizing cultivation techniques and improving bioavailability. Additionally, this review identifies crucial research gaps, particularly in optimizing cultivation techniques, improving bioavailability, and validating the clinical efficacy of C. vulgaris. By addressing these challenges, C. vulgaris holds significant promise in contributing to global health, sustainable nutrition, and environmental conservation efforts by serving as a source of protein and bioactive components for a growing population while simultaneously having a lower environmental impact and requiring fewer resources in production compared to traditional ingredients like soybean meal. Full article

Microalgae have demonstrated biostimulant potential owing to their ability to produce various plant growth-promoting substances, such as amino acids, phytohormones, polysaccharides, and vitamins. Most previous studies have primarily focused on the effects of microalgal biostimulants on plant growth. While biomass extracts are commonly used as biostimulants, research on the use of culture supernatant, a byproduct of microalgal culture, is scarce. In this study, we aimed to evaluate the potential of Chlorella vulgaris culture as a biostimulant and assess its effects on the growth and drought tolerance of Arabidopsis thaliana, addressing the gap in current knowledge. Our results demonstrated that the Chlorella cell-free supernatant (CFS) significantly enhanced root growth and shoot development in both seedlings and mature Arabidopsis plants, suggesting the presence of specific growth-promoting compounds in CFS. Notably, CFS appeared to improve drought tolerance in Arabidopsis plants by increasing glucosinolate biosynthesis, inducing stomatal closure, and reducing water loss. Gene expression analysis revealed considerable changes in the expression of drought-responsive genes, such as IAA5, which is involved in auxin signaling, as well as glucosinolate biosynthetic genes, including WRKY63, MYB28, and MYB29. Overall, C. vulgaris culture-derived CFS could serve as a biostimulant alternative to chemical products, enhancing plant growth and drought tolerance. Full article

Astragali Radix, a traditional Chinese herbal medicine widely used for its medicinal properties, is known to be rich in active components that possess various pharmacological effects. However, the effectiveness of microbial fermentation in enhancing the content of these active substances remains unclear. In this study, a microflora of lactic acid bacteria was used to ferment Astragali Radix, and the promoting effect of Chlorella Growth Factor (CGF) on the fermentation process was investigated so as to clarify the changes in major active compound content in the fermented Astragali Radix broth. Non-targeted metabolomic analysis based on ultra-high-performance liquid chromatography–mass spectrometry was conducted to analyze the differences in metabolites before and after fermentation. The results showed that the total polysaccharide, total flavonoid, and total saponin content in the fermented Astragali Radix broth increased by up to 51.42%, 97.76%, and 72.81% under the optimized conditions, respectively. Streptococcus lutetiensis was the dominant bacterial species during the fermentation process. There were significant differences in metabolites in the fermentation broth before and after fermentation, among which amino acids (such as L-Aspartyl-L-Phenylalanine, etc.) and saponin compounds (such as Cloversaponin I, Goyasaponin I, etc.) were the main upregulated metabolites, which can enhance the physiological functions of Astragali Radix fermentation broth. The CGF exhibited the ability to promote the increase of active substance content in the fermented Astragali Radix broth. Full article

Chlorella sorokiniana, isolated from a pond adjacent to a cement plant, was cultured using flue gas collected directly from kiln emissions using 20 L and 25000 L photobioreactors. Lipids, proteins, and polysaccharides were analyzed to understand their overall composition for potential applications. The lipid content ranged from 17.97% to 21.54% of the dry biomass, with carotenoid concentrations between 8.4 and 9.2 mg/g. Lutein accounted for 55% of the total carotenoids. LC/MS analysis led to the identification of 71 intact triacylglycerols, 8 lysophosphatidylcholines, 10 phosphatidylcholines, 9 monogalactosyldiacylglycerols, 12 digalactosyldiacylglycerols, and 1 sulfoquinovosyl diacylglycerol. Palmitic acid, oleic acid, linoleic acid, and α-linolenic acid were the main fatty acids. Polyunsaturated fatty acid covers ≥ 56% of total fatty acids. Protein isolates and polysaccharides were also extracted. Protein purity was determined to be ≥75% by amino acid analysis, with all essential amino acids present. Monomer analysis of polysaccharides suggested that they are composed of mainly D-(+)-mannose, D-(+)-galactose, and D-(+)-glucose. The results demonstrate that there is no adverse effect on the metabolite profile of C. sorokiniana biomass cultured using flue gas as the primary carbon source, revealing the possibility of utilizing such algal biomass in industrial applications such as animal feed, sources of cosmeceuticals, and as biofuel. Full article