Structural characterization and antioxidant properties of an exopolysaccharide produced by the mangrove endophytic fungus Aspergillus sp. Y16

Endophytic Fungi Volatile Organic Compounds as Crucial Biocontrol Agents Used for Controlling Fruit and Vegetable Postharvest Diseases

Fruits and vegetables are an important part of the human diet, but during transportation and storage, microbial pathogens attack and spoil fruits and vegetables, causing huge economic losses to agriculture. Traditionally used chemical fungicides leave chemical residues, leading to environmental pollution and health risks. With the emphasis on food safety, biocontrol agents are attracting more and more attention due to their environmental friendliness. Endophytic fungi are present in plant tissues and do not cause host disease. The volatile organic compounds (VOCs) they produce are used to control postharvest diseases due to their significant antifungal activity, as well as their volatility, safety and environmental protection characteristics. This review provides the concept and characterization of endophytic fungal VOCs, concludes the types of endophytic fungi that release antifungal VOCs and their biological control mechanisms, as well as focuses on the practical applications and the challenges of applying VOCs as fumigants. Endophytic fungal VOCs can be used as emerging biocontrol resources to control postharvest diseases that affect fruits and vegetables.

Comprehensive review on recent trends and perspectives of natural exo-polysaccharides: Pioneering nano-biotechnological tools

Exopolysaccharides (EPSs), originating from various microbes, and mushrooms, excel in their conventional role in bioremediation to showcase diverse applications emphasizing nanobiotechnology including nano-drug carriers, nano-excipients, medication and/or cell encapsulation, gene delivery, tissue engineering, diagnostics, and associated treatments. Acknowledged for contributions to adsorption, nutrition, and biomedicine, EPSs are emerging as appealing alternatives to traditional polymers, for biodegradability and biocompatibility. This article shifts away from the conventional utility to delve deeply into the expansive landscape of EPS applications, particularly highlighting their integration into cutting-edge nanobiotechnological methods. Exploring EPS synthesis, extraction, composition, and properties, the discussion emphasizes their structural diversity with molecular weight and heteropolymer compositions. Their role as raw materials for value-added products takes center stage, with critical insights into recent applications in nanobiotechnology. The multifaceted potential, biological relevance, and commercial applicability of EPSs in contemporary research and industry align with the nanotechnological advancements coupled with biotechnological nano-cleansing agents are highlighted. EPS-based nanostructures for biological applications have a bright future ahead of them. Providing crucial information for present and future practices, this review sheds light on how eco-friendly EPSs derived from microbial biomass of terrestrial and aquatic environments can be used to better understand contemporary nanobiotechnology for the benefit of society.

Insight of endophytic fungi promoting the growth and development of woody plants

Microorganisms play an important role in plant growth and development. In particular, endophytic fungi is one of the important kinds of microorganisms and has a mutually beneficial symbiotic relationship with host plants. Endophytic fungi have many substantial benefits to host plants, especially for woody plants, such as accelerating plant growth, enhancing stress resistance, promoting nutrient absorption, resisting pathogens and etc. However, the effects of endophytic fungi on the growth and development of woody plants have not been systematically summarized. In this review, the functions of endophytic fungi for the growth and development of woody plants have been mainly reviewed, including regulating plant growth (e.g., flowering, root elongation, etc.) by producing nutrients and plant hormones, and improving plant disease, insect resistance and heavy metal resistance by producing secondary metabolites. In addition, the diversity of endophytic fungi could improve the ability of woody plants to adapt to adverse environment. The components produced by endophytic fungi have excellent potential for the growth and development of woody plants. This review has systematically discussed the potential regulation mechanism of endophytic fungi regulating the growth and development of woody plants, it would be of great significance for the development and utilization of endophytic fungi resource from woody plants for the protection of forest resources.

A New Exopolysaccharide of Marine Coral-Associated Aspergillus pseudoglaucus SCAU265: Structural Characterization and Immunomodulatory Activity

Recent studies have found that many marine microbial polysaccharides exhibit distinct immune activity. However, there is a relative scarcity of research on the immunomodulatory activity of marine fungal exopolysaccharides. A novel water-soluble fungal exopolysaccharide ASP-1 was isolated from the fermentation broths of marine coral-associated fungus Aspergillus pseudoglaucus SCAU265, and purified by Diethylaminoethyl-Sepharose-52 (DEAE-52) Fast Flow and Sephadex G-75. Structural analysis revealed that ASP-1 had an average molecular weight of 36.07 kDa and was mainly composed of (1→4)-linked α-D-glucopyranosyl residues, along with highly branched heteropolysaccharide regions containing 1,4,6-glucopyranosyl, 1,3,4-glucopyranosyl, 1,4,6-galactopyranosyl, T(terminal)-glucopyranosyl, T-mannopyranosyl, and T-galactopyranosyl residues. ASP-1 demonstrated significant effects on the proliferation, nitric oxide levels, and the secretion of cytokines TNF-α and IL-6 in macrophage RAW264.7 cells. Metabolomic analysis provided insights into the potential mechanisms of the immune regulation of ASP-1, suggesting its involvement in regulating immune function by modulating amino acid anabolism, particularly arginine synthesis and metabolism. These findings provide fundamental scientific data for further research on its accurate molecular mechanism of immunomodulatory activity.

Preparation of Hybrid Nanopigments with Excellent Environmental Stability, Antibacterial and Antioxidant Properties Based on Monascus Red and Sepiolite by One-Step Grinding Process

This study is focused on the preparation, characterization, and multifunctional properties of intelligent hybrid nanopigments. The hybrid nanopigments with excellent environmental stability and antibacterial and antioxidant properties were fabricated based on natural Monascus red, surfactant, and sepiolite via a facile one-step grinding process. The density functional theory calculations demonstrated that the surfactants loaded on sepiolite were in favor of enhancing the electrostatic, coordination, and hydrogen bonding interactions between Monascus red and sepiolite. Thus, the obtained hybrid nanopigments exhibited excellent antibacterial and antioxidant properties, with an inhibition effect on Gram-positive bacteria that was superior to that of Gram-negative bacteria. In addition, the scavenging activity on DPPH and hydroxyl free radicals as well as the reducing power of hybrid nanopigments were higher than those of hybrid nanopigments prepared without the addition of the surfactant. Inspired by nature, gas-sensitive reversible alochroic superamphiphobic coatings with excellent thermal and chemical stability were successfully designed by combining hybrid nanopigments and fluorinated polysiloxane. Therefore, intelligent multifunctional hybrid nanopigments have great application foreground in related fields.

Endophytic fungi mediates production of bioactive secondary metabolites via modulation of genes involved in key metabolic pathways and their contribution in different biotechnological sector

Endophytic fungi stimulate the production of an enormous number of bioactive metabolites in medicinal plants and affect the different steps of biosynthetic pathways of these secondary metabolites. Endophytic fungi possess a number of biosynthetic gene clusters that possess genes for various enzymes, transcription factors, etc., in their genome responsible for the production of secondary metabolites. Additionally, endophytic fungi also modulate the expression of various genes responsible for the synthesis of key enzymes involved in metabolic pathways of such as HMGR, DXR, etc. involved in the production of a large number of phenolic compounds as well as regulate the expression of genes involved in the production of alkaloids and terpenoids in different plants. This review aims to provide a comprehensive overview of gene expression related to endophytes and their impact on metabolic pathways. Additionally, this review will emphasize the studies done to isolate these secondary metabolites from endophytic fungi in large quantities and assess their bioactivity. Due to ease in synthesis of secondary metabolites and their huge application in the medical industry, these bioactive metabolites are now being extracted from strains of these endophytic fungi commercially. Apart from their application in the pharmaceutical industry, most of these metabolites extracted from endophytic fungi also possess plant growth-promoting ability, bioremediation potential, novel bio control agents, sources of anti-oxidants, etc. The review will comprehensively shed a light on the biotechnological application of these fungal metabolites at the industrial level.

Plant-growth promoting activity of three fungal endophytes isolated from plants living in dehesas and their effect on Lolium multiflorum

Endophytic fungi have been demonstrated to produce bioactive secondary metabolites, some of which promote plant growth. Three endophytic fungi isolated from healthy plants living in dehesas of Extremadura (Spain) were identified and evaluated for their ability to produce phytohormone-like substances, antioxidant activity, total polyphenol content, phosphate solubilization ability and siderophore and ammonia production. The filtrates and extracts produced by the three endophytes were applied to Lolium multiflorum seeds and seedlings under both in vitro and greenhouse conditions, to analyse their influence on plant growth traits such as germination, vigour index, chlorophyll data, number and length of leaves and roots, and dry weight. All three endophytes, which were identified as Fusarium avenaceum, Sarocladium terricola and Xylariaceae sp., increased the germination of L. multiflorum seeds by more than 70%. Shoot and root length, plant dry weight and the number of roots were positively affected by the application of fungal filtrates and/or extracts, compared with controls. The tentative HPLC-MS identification of phytohormone-like substances, such as gibberellin A2 and zeatin, or the antioxidant acetyl eugenol, may partially explain the mechanisms of L. multiflorum plant growth promotion after the application of fungal filtrates and/or extracts.

Anti-Diabetic Activity of a Novel Exopolysaccharide Produced by the Mangrove Endophytic Fungus Penicillium janthinellum N29

Marine microorganisms often produce exopolysaccharides with novel structures and diverse biological activities due to their specific marine environment. The novel active exopolysaccharides from marine microorganisms have become an important research area in new drug discovery, and show enormous development prospects. In the present study, a homogeneous exopolysaccharide from the fermented broth of the mangrove endophytic fungus Penicillium janthinellum N29, designated as PJ1-1, was obtained. The results of chemical and spectroscopic analyses showed that PJ1-1 was a novel galactomannan with a molecular weight of about 10.24 kDa. The backbone of PJ1-1 was composed of →2)-α-d-Manp-(1→, →4)-α-d-Manp-(1→, →3)-β-d-Galf-(1→ and →2)-β-d-Galf-(1→ units with partial glycosylation at C-3 of →2)-β-d-Galf-(1→ unit. PJ1-1 had a strong hypoglycemic activity in vitro, evaluated using the assay of α-glucosidase inhibition. The anti-diabetic effect of PJ1-1 in vivo was further investigated using mice with type 2 diabetes mellitus induced by a high-fat diet and streptozotocin. The results indicated that PJ1-1 markedly reduced blood glucose level and improved glucose tolerance. Notably, PJ1-1 increased insulin sensitivity and ameliorated insulin resistance. Moreover, PJ1-1 significantly decreased the levels of serum total cholesterol, triglyceride and low-density lipoprotein cholesterol, enhanced the level of serum high-density lipoprotein cholesterol and alleviated dyslipidemia. These results revealed that PJ1-1 could be a potential source of anti-diabetic agent.

Structural characterization and immunomodulatory activity of an exopolysaccharide from marine-derived Aspergillus versicolor SCAU141

Until now, relatively little is known about marine-derived fungal polysaccharides and their activities. Exopolysaccharide AVP141-A was isolated from the broth of marine-derived fungus Aspergillus versicolor SCAU141 and purified by Diethylaminoethyl-Sepharose Fast Flow and Sephadex G-100. The structural characteristics of AVP141-A was studied by chemical analysis together with high-performance gel permeation chromatography, ion chromatography, Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The results showed that AVP141-A with the molecular weight of 5.10 kDa was mainly composed of →4)-α-D-Glcp-(1→, branched by α-D-Glcp-(1→ and →6)-α-D-Glcp-(1→ at C-6 positions of the glucan backbone. In particular, sulfate ester (approximately 3.62 %) was found in AVP141-A, which was frequently considered to occur in marine-derived microbial polysaccharides rather than other microbial polysaccharides. Furthermore, AVP141-A significantly enhanced the activity of the inflammatory factors NO, COX-2 and TNF-α in RAW264.7 macrophages by activating the MAPK/p38 and NF-κB/p65 pathways. In addition, metabolomic analysis revealed that most of the pathways with significant changes in RAW264.7 macrophages treated with AVP141-A were amino acid-related pathways, and arginine was the characteristic metabolite. In conclusion, this study identified AVP141-A as a marine fungus-derived sulfated exopolysaccharide with potential for development as an immune activator.

Drought alleviation efficacy of a galactose rich polysaccharide isolated from endophytic Mucor sp. HELF2: A case study on rice plant

Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the present investigation, a Galactose-Rich Heteropolysaccharide (GRH) with a molecular weight of 2.98 × 10⁵ Da was isolated from endophytic Mucor sp. HELF2, a symbiont of the East Indian screw tree Helicteres isora. OVAT (One Variable at A Time) experiment coupled with RSM (Response Surface Methodology) study exhibited 1.5-fold enhanced GRH production (20.10 g L^-1) in supplemented potato dextrose broth at a pH of 7.05 after 7.5 days of fermentation in 26°C. GRH has alleviated drought stress (polyethylene glycol induced) in rice seedlings (Oryza sativa ssp. indica MTU 7093 swarna) by improving its physicochemical parameters. It has been revealed that spray with a 50-ppm dosage of GRH exhibited an improvement of 1.58, 2.38, 3, and 4 times in relative water contents and fresh weight of the tissues, root length, and shoot length of the rice seedlings, respectively "in comparison to the control". Moreover, the soluble sugars, prolines, and chlorophyll contents of the treated rice seedlings were increased upto 3.5 (0.7 ± 0.05 mg/g fresh weight), 3.89 (0.57 ± 0.03 mg/g fresh weight), and 2.32 (1,119 ± 70.8 μg/gm of fresh weight) fold respectively, whereas malondialdehyde contents decreased up to 6 times. The enzymatic antioxidant parameters like peroxidase and superoxide dismutase and catalase activity of the 50 ppm GRH treated seedlings were found to be elevated 1.8 (720 ± 53 unit/gm/min fresh weight), 1.34 (75.34 ± 4.8 unit/gm/min fresh weight), and up to 3 (100 ppm treatment for catalase - 54.78 ± 2.91 unit/gm/min fresh weight) fold, respectively. In this context, the present outcomes contribute to the development of novel strategies to ameliorate drought stress and could fortify the agro-economy of India.

Purification, structural elucidation and biological activities of exopolysaccharide produced by the endophytic Penicillium javanicum from Millettia speciosa Champ

An acid polysaccharide, named HP, was produced by endophytic Penicillium javanicum MSC-R1 isolated from southern medicine Millettia speciosa Champ. The molecular weight of HP was 37.8 kDa and consisted of Ara f, Galр, Glcр, Manр, and GlcрA with a molar ratio of 1.09: 3.47: 68.48: 16.59: 8.85. The glycosidic linkage of HP was proven to be →3, 4)-α-D-Glcр-(1→6)-α-D-Manр-(1→, →3, 4)-α-D-Glcр-(1→4)-α-D-Glcр-(1→, →3), →6)-α-D-Manр-(1→4)-α-D-Glcр-(1→, →3), β-D-Galр-(1→3)-α-D-Glcр-(1→, →4), →5)-α-L-Ara f -(1→3)-α-D-Glcр-(1→, →4), →6)-α-D-Manр-(1→4)-α-D-GlcAр-(1→ and →4)-α-D-GlcAр-(1→4)-α-D-Glcр-(1→, →3). Additionally, 250 μg/mL of HP possessed nontoxicity to RAW 264.7 cells and exhibited anti-inflammation activity. HP could significantly restrain the amount of tumor necrosis factor-α, interleukin-6 and NO release in RAW264.7, which property is possibly associated with its abundant glucosidic linkage. These results indicated that HP could be regarded as a ponderable ingredient for the health-beneficial functional foods.

Pestalotiopsis Diversity: Species, Dispositions, Secondary Metabolites, and Bioactivities

Pestalotiopsis species have gained attention thanks to their structurally complex and biologically active secondary metabolites. In past decades, several new secondary metabolites were isolated and identified. Their bioactivities were tested, including anticancer, antifungal, antibacterial, and nematicidal activity. Since the previous review published in 2014, new secondary metabolites were isolated and identified from Pestalotiopsis species and unidentified strains. This review gathered published articles from 2014 to 2021 and focused on 239 new secondary metabolites and their bioactivities. To date, 384 Pestalotiopsis species have been discovered in diverse ecological habitats, with the majority of them unstudied. Some may contain secondary metabolites with unique bioactivities that might benefit pharmacology.

Optimization and Characterization of a Novel Exopolysaccharide from Bacillus haynesii CamB6 for Food Applications

Extremophilic microorganisms often produce novel bioactive compounds to survive under harsh environmental conditions. Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, are functional biopolymers that act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermophilic Bacillus haynesii CamB6 from a slightly acidic (pH 5.82) Campanario hot spring (56.4 °C) located in the Central Andean Mountains of Chile. Physicochemical properties of the EPS were characterized by different techniques: Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), 1D and 2D Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps. GPC and HPLC analysis showed that the EPS is a low molecular weight heteropolymer composed of mannose (66%), glucose (20%), and galactose (14%). FTIR analysis demonstrated the polysaccharide nature (–OH groups, Acetyl groups, and pyranosic ring structure) and the presence of different glycosidic linkages among sugar residues, which was further confirmed by NMR spectroscopic analyses. Moreover, D-mannose α-(1→2) and α-(1→4) linkages prevail in the CamB6 EPS structure. TGA revealed the high thermal stability (240 °C) of the polysaccharide. The functional properties of the EPS were evaluated for food industry applications, specifically as an antioxidant and for its emulsification, water-holding (WHC), oil-holding (OHC), and flocculation capacities. The results suggest that the study EPS can be a useful additive for the food-processing industry.

Antidiabetic-activity sulfated polysaccharide from Chaetomorpha linum: Characteristics of its structure and effects on oxidative stress and mitochondrial function

A water-soluble polysaccharide from the green alga Chaetomorpha linum, designated CHS2, was obtained by water extraction, preparative anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that CHS2 was a sulfated rhamnogalactoarabinan, and its backbone was mainly constituted by 4-linked and 3,4-linked β-l-arabinopyranose with sulfate groups at C-2/C-3 of 4-linked β-l-arabinopyranose. The branching contained 4-linked, 6-linked β-d-galactopyranose and terminal rhamnose residues. Based on the inhibition of human islet amyloid polypeptide (hIAPP) aggregation and morphology change of hIAPP aggregates in in vitro tests, it was proved that CHS2 effectively inhibited the hIAPP aggregation and possessed strong antidiabetic activity. CHS2 was nearly no toxicity in NIT-1 cells and could attenuate hIAPP-induced cytotoxicity. CHS2 may significantly reduce the generation of intracellular reactive oxygen species and hIAPP aggregation-induced oxidative stress in NIT-1 cells. CHS2 was co-localized with mitochondria, and largely protected mitochondria function from hIAPP aggregation-induced damage through stabilizing mitochondrial membrane potential and enhancing the mitochondrial complex I, II or III activity and ATP level. The data demonstrated that CHS2 could have potential prospect to become an antidiabetic drug for type 2 diabetes mellitus treatment.

Assessment of Biological Activities of Fungal Endophytes Derived Bioactive Compounds Isolated from Amoora rohituka

Fungal endophytes have remarkable potential to produce bioactive compounds with numerous pharmacological significance that are used in various disease management and human welfare. In the current study, a total of eight fungal endophytes were isolated from the leaf tissue of Amoora rohituka, and out of which ethyl acetate (EA) extract of Penicillium oxalicum was found to exhibit potential antioxidant activity against DPPH, nitric oxide, superoxide anion and hydroxyl free radicals with EC₅₀ values of 178.30 ± 1.446, 75.79 ± 0.692, 169.28 ± 0.402 and 126.12 ± 0.636 µg/mL, respectively. The significant antioxidant activity of EA extract of P. oxalicum is validated through highest phenolic and flavonoid content, and the presence of unique bioactive components observed through high-performance thin layer chromatography (HPTLC) fingerprinting. Moreover, EA extract of P. oxalicum also displayed substantial anti-proliferative activity with IC₅₀ values of 56.81 ± 0.617, 37.24 ± 1.26 and 260.627 ± 5.415 µg/mL against three cancer cells HuT-78, MDA-MB-231 and MCF-7, respectively. Furthermore, comparative HPTLC fingerprint analysis and antioxidant activity of P. oxalicum revealed that fungal endophyte P. oxalicum produces bioactive compounds in a host-dependent manner. Therefore, the present study signifies that fungal endophyte P. oxalicum associated with the leaf of A. rohituka could be a potential source of bioactive compounds with antioxidant and anticancer activity.

Enhancement of polysaccharides production using microparticle enhanced technology by Paraisaria dubia

Background

Polysaccharides are important active ingredients in Ophiocordyceps gracilis with many physiological functions. It can be obtained from the submerged fermentation by the anamorph (Paraisaria dubia) of Ophiocordyceps gracilis. However, it was found that the mycelial pellets of Paraisaria dubia were dense and increased in volume in the process of fermentation, and the center of the pellets was autolysis due to the lack of nutrient delivery, which extremely reduced the yield of polysaccharides. Therefore, it is necessary to excavate a fermentation strategy based on morphological regulation for Paraisaria dubia to promote polysaccharides accumulation.

Results

In this study, we developed a method for enhancing polysaccharides production by Paraisaria dubia using microparticle enhanced technology, talc microparticle as morphological inducer, and investigated the enhancement mechanisms by transcriptomics. The optimal size and dose of talc were found to be 2000 mesh and 15 g/L, which resulted in a high polysaccharides yield. It was found that the efficient synthesis of polysaccharides requires an appropriate mycelial morphology through morphological analysis of mycelial pellets. And, the polysaccharides synthesis was found to mainly rely on the ABC transporter-dependent pathway revealed by transcriptomics. This method was also showed excellent robustness in 5-L bioreactor, the maximum yields of intracellular polysaccharide and exopolysaccharides were 83.23 ± 1.4 and 518.50 ± 4.1 mg/L, respectively. And, the fermented polysaccharides were stable and showed excellent biological activity.

Conclusions

This study provides a feasible strategy for the efficient preparation of cordyceps polysaccharides via submerged fermentation with talc microparticles, which may also be applicable to similar macrofungi.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01733-w.

Production, Optimization, Characterization and Drought Stress Resistance by β-Glucan-Rich Heteropolysaccharide From an Endophytic Fungi Colletotrichum alatae LCS1 Isolated From Clubmoss (Lycopodium clavatum)

Endophytic entities are ubiquitous in nature with all-square bioactivity ranging from therapeutic effects toward animals to growth promoting attributes and stress tolerance activities in case of green plants. In the present study, the club moss Lycopodium clavatum for the first time has been subjected for the isolation of endophytic fungi. An exopolysaccharide (EPS) extracted from Colletotrichum alatae LCS1, an endophytic fungi isolated from L. clavatum Linn., was characterized as a β-glucan heteropolymer (composed of mannose, rhamnose, arabinose, glucose, galactose, and fucose) which plays a pivotal role in obliterating the drought stress in rice seedlings (Oryza sativa) when applied at an amount of 20, 50, and 100 ppm. The fresh weight contents of rice tissue (39%), total chlorophyll (33%), proline (41%), soluble sugar content (26%) along with antioxidant enzymes such as catalase, peroxidase, and super-oxide dismutase increased (in comparison to control of non-EPS treated seedlings) while malondialdehyde content had reduced markedly after 30 days of regular treatment. The drought resistance of rice seedling was observed at peak when applied at 50 ppm dosage. Vital parameters for EPS production like fermentation duration (5 days), medium pH (6), nutrient (carbon (glucose-7 g%/l), nitrogen (yeast extract-0.4 g%/l), and mineral (NaCl-0.10 g%/l) sources, oxygen requirements (O2 vector or liquid alkane-n-hexane, n-heptane, n-hexadecane), and headspace volume (250 ml Erlenmeyer flask- 50 ml medium, 200 ml-headspace volume) were optimized to obtain an enhanced EPS yield of 17.38 g/L-59% higher than the preoptimized one. The present study, for the first time, reported the β-glucan rich heteropolysaccharide from Colletotrichum origin which is unique in structure and potent in its function of drought stress tolerance and could enhance the sustainable yield of rice cultivation in areas facing severe drought stress.

Structural characterization and immunomodulatory activity of mycelium polysaccharide from liquid fermentation of Monascus purpureus (Hong Qu)

Alkaline extracted endopolysaccharides (MPS) from Monascus purpureus (Hong Qu) mycelium were successfully separated into four sub-fractions, namely MPS-1 (18.0 %), MPS-2 (27.1 %), MPS-3 (12.6 %) and MPS-4 (14.7 %), by DEAE-Cellulose column chromatography. By combining monosaccharide composition analysis, methylation analysis and 1D & 2D NMR, the structure of sub-fractions was systematically characterized. Both MPS-1 and MPS-2 were comprised of mannose, glucose and galactose in the molar ratio of 1.5:1.6:1.0 and 10.6:1.0:13.8, respectively. The backbone of them both consisted of 2-α-Manp with several different branched chains. However, MPS-1 contained glucose based sugar residues such as 3-Glcp and 4-Glcp which were not shown on MPS-2. The proposed structures of MPS-3 and MPS-4 were not obtained due to the fairly complex molecular structure and relatively low yield. Moreover, based on the RAW 264.7 cells model, MPS-2 could significantly promote cytokines secretion including IL-6, TNF-α, and IL-10 and improve expression levels of the related mRNA.

Two new exopolysaccharides from a thermophilic bacterium Geobacillus sp. WSUCF1: Characterization and bioactivities

The production, characterization and bioactivities of exopolysaccharides (EPSs) from a thermophilic bacterium Geobacillus sp. strain WSUCF1 were investigated. Using glucose as a carbon source 525.7 mg/L of exoproduct were produced in a 40-L bioreactor at 60 °C. Two purified EPSs were obtained: EPS-1 was a glucomannan containing mannose and glucose in a molar ratio of 1:0.21, while EPS-2 was composed of mannan only. The molecular weights of both EPSs were estimated to be approximately 1000 kDa, their FTIR and NMR spectra indicated the presence of α-type glycosidic bonds in a linear structure, and XRD analysis indicated a low degree of crystallinity of 0.11 (EPS-1) and 0.27 (EPS-2). EPS-1 and EPS-2 demonstrated high degradation temperatures of 319 °C and 314 °C, respectively, and non-cytotoxicity to HEK-293 cells at 2 and 3 mg/mL, respectively. In addition, both showed antioxidant activities. EPSs from strain WSUCF1 may expand the applications of microorganisms isolated from extreme environments and provide a valuable resource for exploitation in biomedical fields such as drug delivery carriers.

Fungi in mangrove ecosystems and their potential applications

Mangrove fungi, their ecological role in mangrove ecosystems, their bioproducts, and potential applications are reviewed in this article. Mangrove ecosystems can play an important role in beach protection, accretion promotion, and sheltering coastlines and creeks as barriers against devastating tropical storms and waves, seawater, and air pollution. The ecosystems are characterized by high average and constant temperatures, high salinity, strong winds, and anaerobic muddy soil. The mangrove ecosystems also provide the unique habitats for the colonization of fungi which can produce different kinds of enzymes for industrial uses, recycling of plants and animals in the ecosystems, and the degradation of pollutants. Many mangrove ecosystem-associated fungi also can produce exopolysaccharides, Ca²⁺-gluconic acid, polymalate, liamocin, polyunsaturated fatty acids, biofuels, xylitol, enzymes, and bioactive substances, which have many potential applications in the bioenergy, food, agricultural, and pharmaceutical industries. Therefore, mangrove ecosystems are rich bioresources for bioindustries and ecology. It is necessary to identify more mangrove fungi and genetically edit them to produce a distinct array of novel chemical entities, enzymes, and bioactive substances.

A Glacier Bacterium Produces High Yield of Cryoprotective Exopolysaccharide

Pseudomonas sp. BGI-2 is a psychrotrophic bacterium isolated from the ice sample collected from Batura glacier, Pakistan. This strain produces highly viscous colonies on agar media supplemented with glucose. In this study, we have optimized growth and production of exopolysaccharide (EPS) by the cold-adapted Pseudomonas sp. BGI-2 using different nutritional and environmental conditions. Pseudomonas sp. BGI-2 is able to grow in a wide range of temperatures (4-35°C), pH (5-11), and salt concentrations (1-5%). Carbon utilization for growth and EPS production was extensively studied and we found that glucose, galactose, mannose, mannitol, and glycerol are the preferable carbon sources. The strain is also able to use sugar waste molasses as a growth substrate, an alternative for the relatively expensive sugars for large scale EPS production. Maximum EPS production was observed at 15°C, pH 6, NaCl (10 g L-1), glucose as carbon source (100 g L-1), yeast extract as nitrogen source (10 g L-1), and glucose/yeast extract ratio (10/1). Under optimized conditions, EPS production was 2.01 g L-1, which is relatively high for a Pseudomonas species compared to previous studies using the same method for quantification. High-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) analysis of EPS revealed glucose, galactose, and glucosamine as the main sugar monomers. Membrane protection assay using human RBCs revealed significant reduction in cell lysis (∼50%) in the presence of EPS, suggesting its role in membrane protection. The EPS (5%) also conferred significant cryoprotection for a mesophilic Escherichia coli k12 which was comparable to glycerol (20%). Also, improvement in lipid peroxidation inhibition (in vitro) resulted when lipids from the E. coli was pretreated with EPS. Increased EPS production at low temperatures, freeze thaw tolerance of the EPS producing strain, and increased survivability of E. coli in the presence of EPS as cryoprotective agent supports the hypothesis that EPS production is a strategy for survival in extremely cold environments such as the glacier ice.

Production, Preparation and Characterization of Microalgae-Based Biopolymer as a Potential Bioactive Film

Six microalgae strains were screened according to their biomass productivity and polymer synthesis, showing biomass productivity between 0.14 and 0.68 g/(L·d) for a 21-day growth period. Extracellular biopolymers from the spent culture media of Nostoc sp. (No), Synechocystis sp. (Sy), and Porphyridium purpureum (Pp) was obtained, and the yields of the clean biopolymer were 323, 204, and 83 mg/L, respectively. The crude biopolymer was cleaned up using a solid-phase extraction technique. The emulsification index E24 values for the clean biopolymer were 77.5%, 68.8%, and 73.3% at 0.323, 0.083, and 0.204 mg/mL, respectively. The clean biopolymer of the No strain showed the highest fungal growth inhibition against Fusarium verticillioides (70.2%) and Fusarium sp. (61.4%) at 2.24 mg/mL. In general, transparent and flexible biofilms were prepared using biopolymers of No and Pp. The microstructural analysis revealed the presence of pores and cracks in the biofilms, and the average roughness Ra values are 68.6 and 86.4 nm for No and Pp, respectively, and the root mean square roughness Rq values are 86.2 and 107.2 nm for No and Pp, respectively.

Purification, structural characterization, and immunomodulatory activity of the polysaccharides from Ganoderma lucidum

A preliminary relationship was illustrated between the structural characteristics and corresponding immunomodulatory activities of G. lucidum polysaccharides. Two polysaccharides (GLP-1 and GLP-2) were purified from Ganoderma lucidum extracts by gradient ethanol precipitation and a Q-Sepharose Fast Flow (QFF) strong anion-exchange column. The monosaccharide composition, high-performance gel permeation chromatography-multi-angle laser light scattering-refractive index (HPGPC-MALLS-RI), Fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), methylation analysis, and nuclear magnetic resonance (NMR) were used to characterize these polysaccharides. The GLP-1 polysaccharide was elucidated as d-galactoglucan with a flexible random linear conformation that mainly composed of →6)-β-d-Glcp-(1→, →6)-α-d-Galp-(1→, and →3)-β-d-Glcp-(1→ residues. GLP-2 was found to be a relatively homogeneous β-d-glucan that possessing →6)-β-d-Glcp-(1→ and →3)-β-d-Glcp-(1→ residues packaged into a spherical conformation. Immunomodulatory activities in vivo demonstrated that GLP-1 produced better protection of the spleen and thymus and was more effective for promoting hematopoiesis and improving IgA levels in serum. Our results suggest that the immunomodulatory activities of G. lucidum polysaccharides are highly corresponded to their structural characteristics such as carbohydrate composition, molecular weight and advanced conformation. This study provides a preliminary basis for studying the relationship between polysaccharide structure characterization and pharmacological activities.

Novel antibacterial polysaccharides produced by endophyte Fusarium solani DO7

In this study, the primary antibacterial ingredients in Fusarium solani DO7 were confirmed as polysaccharides. After purification, two polysaccharides, DY1 and DY2, exhibited excellent antibacterial activity, especially to S. aureus and E. coli. Moreover, the glycosidic linkages of DY1 were composed of (1 → )-α-D-Glcp, (1 → 3)-β-L-Rhaf, (1 → 4)-β-D-Xylp, (1 → 6)-α-D-Glcp, (1 → 2,6)-α-D-Glcp and (1 → 2)-β-D-Galp; while the glycosidic linkages of DY2 contained (1 → )-β-D-Glcp, (1 → 2)-α-L-Rhaf, (1 → 3)-α-L-Araf, (1 → 4)-β-D-Glcp, (1 → 4,6)-β-D-Glcp and (1 → 3)-α-D-Galp. Additionally, DY1 and DY2 possessed nontoxicity to RAW 264.7 cells. Both polysaccharides could significantly promote the levels of TNF-α, IL-6 and NO by activating TNF-α, IL-6 and iNOs mRNAs expression. These results indicated that DY1 and DY2 had great potential as a food preservative and immunomodulatory agent.

How Fermentation Affects the Antioxidant Properties of Cereals and Legumes

The major role of antioxidant compounds in preserving food shelf life, as well as providing health promoting benefits, combined with the increasing concern towards synthetic antioxidants, has led the scientific community to focus on natural antioxidants present in food matrices or resulting from microbial metabolism during fermentation. This review aims at providing a comprehensive overview of the effect of fermentation on the antioxidant compounds of vegetables, with emphasis on cereals- and legumes- derived foods. Polyphenols are the main natural antioxidants in food. However, they are often bound to cell wall, glycosylated, or in polymeric forms, which affect their bioaccessibility, yet several metabolic activities are involved in their release or conversion in more active forms. In some cases, the antioxidant properties in vitro, were also confirmed during in vivo studies. Similarly, bioactive peptides resulted from bacterial and fungal proteolysis, were also found to have ex vivo protective effect against oxidation. Fermentation also influenced the bioaccessibility of other compounds, such as vitamins and exopolysaccharides, enabling a further improvement of antioxidant activity in vitro and in vivo. The ability of fermentation to improve food antioxidant properties strictly relies on the metabolic activities of the starter used, and to further demonstrate its potential, more in vivo studies should be carried out.

Characterization of the antioxidant and anti-inflammatory properties of a polysaccharide-based bioflocculant from Bacillus subtilis F9

Microbial flocculants are versatile class of novel biomacromolecules with numerous potential industrial applications. This study sought to investigate the antimicrobial, antioxidant, and anti-inflammatory potential of a polysaccharide-based bioflocculant (PBB) extracted from Bacillus subtilis F9. To achieve this, the antioxidant activity of different PBB concentrations(100 μg/mL ̶ 1000 μg/mL) was first examined in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radicals, and superoxide radical scavenging assays. Further, the anti-inflammatory activity of PBB against lipopolysaccharide (LPS; 1 μg/mL)-induced inflammatory mediators released from headkidney (HK)-derived macrophages of Labeo rohita was investigated. Our results revealed that the capacities of 800 μg/mL of PBB to scavenge DPPH, hydroxyl radicals, and superoxide radicals were 81.46 ± 1.37%, 66.34 ± 2.63%, and 78.03 ± 2.46%, respectively, which were slightly higher that observed following treatment with 400 μg/mL of the positive control (ascorbic acid). Further, the radical scavenging capacity of PBB was found to steadily increase with increasing concentrations of PBB. Pre-treatment with PBB also inhibited nitric oxide production in a dose-dependent manner. We next examined the effect of PBB on proinflammatory cytokines (TNF-α, and IL-1β) and anti-inflammatory cytokines (IL-10, TGF-β) via qRT-PCR and ELISA. We found that PBB markedly inhibited the LPS-induced mRNA and protein expression levels of TNF-α and IL-1β, while it significantly increased those of IL-10 and TGF-β. Further, PBB exhibited an antibacterial activity against multiple food-borne pathogens with minimal inhibitory concentration values in the range of 3 ̶ 11 mg/mL. Importantly, PBB exhibited negligible cytotoxic effects against HK macrophages. Taken together these results suggest that PBB may serve as a natural antioxidant for application in functional therapies and may also be exploited for its anti-inflammatory potential.

Terrestrial Microorganisms: Cell Factories of Bioactive Molecules with Skin Protecting Applications

It is well known that terrestrial environments host an immense microbial biodiversity. Exposed to different types of stress, such as UV radiation, temperature fluctuations, water availability and the inter- / intra-specific competition for resources, terrestrial microorganisms have been evolved to produce a large spectrum of bioactive molecules. Bacteria, archaea, protists, fungi and algae have shown a high potential of producing biomolecules for pharmaceutical or other industrial purposes as they combine a sustainable, relatively low-cost and fast-production process. Herein, we provide an overview of the different bioactive molecules produced by terrestrial microorganisms with skin protecting applications. The high content in polyphenolic and carotenoid compounds produced by several strains, as well as the presence of exopolysaccharides, melanins, indole and pyrrole derivatives, mycosporines, carboxylic acids and other molecules, are discussed in the context of their antioxidant, photo-protective and skin-whitening activity. Relevant biotechnological tools developed for the enhanced production of high added value natural products, as well as the protecting effect of some antioxidant, hydrolytic and degrading enzymes are also discussed. Furthermore, we describe classes of microbial compounds that are used or have the potential to be used as antimicrobials, moisturizers, biosurfactants, pigments, flavorings and fragrances.

Exopolysaccharides from the fungal endophytic Fusarium sp. A14 isolated from Fritillaria unibracteata Hsiao et KC Hsia and their antioxidant and antiproliferation effects

Exopolysaccharides (EPSs) are high-molecular-weight carbohydrates with a wide range of biophysiological activities, such as antioxidant activity, immunostimulatory activity, antitumor activity, hepatoprotective activity, and antifatigue effects. In the present work, two water-soluble EPSs, namely, A14EPS-1 and A14EPS-2, were isolated and purified from the fungal endophytic strain A14 using ethanol precipitation, DEAE-cellulose ion exchange chromatography and Sepharose G-150 gel filtration chromatography. A14EPS-1 (∼2.4 × 10⁴ Da, the major fraction) was mainly composed of mannose, rhamnose, glucose, galactose, xylose and arabinose with a molar ratio of 0.31:0.55:10.00:0.34:0.03:0.06. The major monosaccharide of A14EPS-1 was pyranose, which was connected by α-glycosidic linkages. And the side chains of A14EPS-1 may be composed of rhamnose, arabinose, glucose and galactose; moreover, the backbone of A14EPS-1 may be composed of rhamnose, xylose, arabinose and glucose. A14EPS-2 (∼0.5 × 10⁴ Da) was mainly composed of mannose, rhamnose, glucose, galactose, xylose and arabinose in a ratio of 0.16:0.88:10.00:0.39:0.06:0.06. Pyranose was observed in both the α- and β-configurations in A14EPS-2, and the α configuration was dominant. In addition, the results of the bioactivity assays indicated that both A14EPS-1 and A14EPS-2 had moderate antioxidant activity in vitro, and A14EPS-2 showed a moderate antiproliferation effect on human hepatocellular carcinoma HepG2 cells.

Chemical characterization and antioxidant properties of exopolysaccharides from mangrove filamentous fungi Fusarium equiseti ANP2

A filamentous fungi F. equiseti strain ANP2 with good exopolysaccharide (EPS) yield, apparent viscosity was screened and isolated from Krishna estuarine mangrove sediments. Based on molecular characteristics the selected strain was confirmed as F. equiseti, yielded EPS (4.9 ± 0.25 g/L) and whole cell biomass (3.5 ± 0.2 g/L) in MSM during early stationary phase. The crude EPS was purified by chromatography of Q-Sepharose and Superdex-75, affording Ms and MF-1 fractions were obtained, respectively. Chemical analyses revealed that EPS is primarily composed of neutral sugars and proteins. FTIR-spectroscopy revealed presence of hydroxyl, carbonyl groups and glycosidic bonds which correspond to typical heteropolysaccharide. GC analysis demonstrated that MF-1 mainly consist of mannose (72.6%) and glucose (27.3%). Viscosity studies exhibited typical non-Newtonian pseudoplastic behaviour with high viscosity. The scavenging ability on hydroxyl radicals, indicate that MF-1-EPS has good antioxidant activity. Current study demonstrated that MF-1 differed from previously characterized Fusarium sp., and can serve as potential antioxidant.

Production of bioproducts by endophytic fungi: chemical ecology, biotechnological applications, bottlenecks, and solutions

Endophytes are microorganisms that colonize the interior of host plants without causing apparent disease. They have been widely studied for their ability to modulate relationships between plants and biotic/abiotic stresses, often producing valuable secondary metabolites that can affect host physiology. Owing to the advantages of microbial fermentation over plant/cell cultivation and chemical synthesis, endophytic fungi have received significant attention as a mean for secondary metabolite production. This article summarizes currently reported results on plant-endophyte interaction hypotheses and highlights the biotechnological applications of endophytic fungi and their metabolites in agriculture, environment, biomedicine, energy, and biocatalysts. Current bottlenecks in industrial development and commercial applications as well as possible solutions are also discussed.

Production and Bioactivity-Guided Isolation of Antioxidants with α-Glucosidase Inhibitory and Anti-NO Properties from Marine Chitinous Materials

Natural and bioactive products have been of great interest due to their benefit as health foods and drugs to prevent various diseases. The aim of this study is to efficiently reuse marine chitinous materials (CMs), abundant and low-cost fishery by-products, for the bio-synthesis, isolation, and identification of antioxidant compounds possessing some other beneficial bioactivities. Paenibacillus sp. was used to convert CMs to antioxidants. Among various tested CMs, squid pen powder (SPP) gave the best results when used as the sole carbon/nitrogen source. Fermented SPP (FSPP) had comparable antioxidant activity (IC50 = 124 µg/mL) to that of α-tocopherol (IC50 = 30 µg/mL). The antioxidant productivity increased 1.83-fold after culture optimization. The use of multiple techniques, including Diaion, silica, and preparative HPLC columns coupled with a bioassay resulted in the isolation of two major antioxidants characterized as exopolysaccharides and homogentisic acid. These isolated compounds showed great maximum activity and low IC50 values (96%, 30 µg/mL and 99%, 5.4 µg/mL, respectively) which were comparable to that of α-tocopherol (95%, 24 µg/mL). The crude sample, fractions, and isolated compounds also demonstrated α-glucosidase inhibition and anti⁻inflammatory activity. Notably, homogentisic acid was found as a non-sugar-based moiety α-glucosidase inhibitor which show much higher inhibition (IC50 = 215 µg/mL) than that of acarbose (IC50 = 1324 µg/mL) and also possessed acceptable anti⁻inflammatory activity (IC50 = 9.8 µg/mL). The results highlighted the value of using seafood processing by-products, like squid pens, for the production of several compounds possessing multi-benefit bioactivities and no cytotoxicity.

Engineering aspects of microbial exopolysaccharide production

Although the ability to secrete exopolysaccharides (EPS) is widespread among microorganisms, only a few bacterial (e.g. xanthan, levan, dextran) and fungal (e.g. pullulan) EPS have reached full commercialization. During the last years, other microbial EPS producers have been the subject of extensive research, including endophytes, extremophiles, microalgae and Cyanobacteria, as well as mixed microbial consortia. Those studies have demonstrated the great potential of such microbial systems to generate biopolymers with novel chemical structures and distinctive functional properties. In this work, an overview of the bioprocesses developed for EPS production by the wide diversity of reported microbial producers is presented, including their development and scale-up. Bottlenecks that currently hinder microbial EPS development are identified, along with future prospects for further advancement.

Production of Exopolysaccharide from Local Fungal Isolate

The study investigated in isolation of 26 fungal isolates belonging to 6 different genera viz., Penicillium sp., Aspergillus sp. , Fusarium sp., Alternaria sp., , Rhizopus sp. and Phoma sp. Were screened for exopolysaccharide production. Glucose in culture media was studied to select the medium that gives a maximum production of exopolysaccharide by Penicillium sp., Exopolysaccharide was isolated by ethanol precipitation. The medium which contains glucose had been selected to get the heights production of exopolysaccharide . Fermentation conditions were further investigated to optimize exopolysaccharide production by Penicillium sp. , The optimum substitution ratio, temperatures, pH and incubation periods for the maximum production of the polysaccharide were 100% , 30 ˚C , pH 5 and 9 days respectively. Characteristic of exopolysaccharide compounds were observed in the FTIR spectrum. Thin layer chromatography of the hydrolyzed polysaccharide showed that the exopolysaccharide production was heteropolysaccharide consists of galactose, glucose and mannose.