High Polysaccharide Content Research Articles

Purification, structural characterization, and biological activities of degraded polysaccharides from Porphyra yezoensis.

The degraded polysaccharides from Porphyra yezoensis (DPPY) prepared using the H2 O2 -Vc method under optimized conditions were isolated and purified by DEAE Cellulose-52, and Sephadex G-100, providing four pure components, namely, DPPY-0, DPPY-0.1, DPPY-0.3, and DPPY-0.5. Their relative molecular weights were measured to be 10.8, 10.7, 18.7, and 35.5kDa, respectively. GC-MS analysis revealed that all the four fractions were mainly composed of galactose, together with a small portion of glucose, mannose, xylose, and rhamnose. Structural analysis revealed that the purified polysaccharides mainly possess a backbone of (1→3)-β-D-galactose (1→4)-3,6-anhydro-α-L-galactopyranose (G-A) units and (1→3)-β-D-galactose (1→4)-α-L-galactose-6-sulfate (G-L6S) units. They were found to promote the proliferation of RAW264.7 macrophages and enhance phagocytosis of the RAW264.7 cells. Antioxidant assays indicated that DPPY-0.5 possessed the most potent reducing power and free radical scavenging ability among the four purified polysaccharides. High sulfate content and proper molecular weight of these fractions are favorable to their immunomodulatory and antioxidant activities. PRACTICAL APPLICATIONS: Porphyra yezoensis, common economic red algae widely distributed in East Asian countries, contains a high content of polysaccharides with a variety of biological activities. However, P. yezoensis polysaccharide (PPY) has not been well utilized due to the relatively low biological activities and lack of understanding of its structure-activity relationship. Thus, it is necessary to improve the bioactivities and elucidate the structure-activity relationship of this polysaccharide for its practical use. In the present work, four purified fractions (DPPY-0, DPPY-0.1, DPPY-0.3, and DPPY-0.5) were isolated from the degraded P. yezoensis polysaccharide, and were investigated for their antioxidant and immunoregulatory activities. The results of the present work will lay a foundation for the application of the degraded P. yezoensis polysaccharide in the food industry as a functional food ingredient.

Role of Microalgae in Sustainable Energy and Environment

The fast-growing global population is pressing the requirement of energy leading to the extensive use of fossil fuels globally which tends to their exhaustion, alongside the environmental pollution. The need of a third-generation fuel which is viably sustainable has increased and for that microalgae are standing out among various other competitors. Microalgae may be prokaryotic, like cyanobacteria or eukaryotic, like green algae. They are highly efficient in converting solar energy into biomass and can be cultivated in a wide range of conditions. Microalgae are the sources of biofuels, bioactive medicinal products, and food supplements. They have an outstanding photosynthetic efficiency and biomass productivity with high contents of fatty acids, polysaccharides, and proteins. Biofuels derived from microalgae have immense potential for carbon dioxide (CO2) sequestration, whereby 1 kg of algal biomass may fix 1.8 kg of CO2. Microalgae are termed as ‘living biorefinery’ because they can produce a wide range of green chemicals like biopesticides and biofertilizers. Keeping in mind the severe impacts of chemical fertilizers, sustainable agricultural system is opting for biofertilizers and biopesticides. Biopesticides help prevents the attack of pathogenic fungus and soil borne diseases without causing any harm to plants and environment. The remarkable features of biofertilizers include enhanced crop productivity per area; reduced amount of energy consumption and contamination of soil and water; and increased soil fertility. Biofuels derived from microalgae are of various kinds including Biochar (solid); bioethanol, biodiesel, and vegetable oil (liquid); bio hydrogen and bio syngas (gaseous). Some of the pros of bioethanol obtained from microalgae are high octane number, minimal production of greenhouse gases, and the exclusive biofuel which can directly be used in automotive industry. This paper will provide an insight on the viability and feasibility of microalgal biomass in the production of biofuels and other bioactive compounds with the constraints and challenges faced in commercializing these products. This review shall elaborate on the potential of microalgae as a sustainable solution for future energy crises and environmental deterioration.

Edible films based on gelatin, carboxymethyl cellulose, and their blends as carriers of potassium salts of iso-α-acids: Structural, physicochemical and antioxidant properties

Edible films based on gelatin/carboxymethyl cellulose (GEL/CMC) blends (100/0, 75/25, 50/50, 25/75, and 0/100) incorporated with increasing concentrations (0, 15, 30, 60 mg/100g) of potassium salts of iso-α-acids (KIAA) were prepared and characterized. Mixing of GEL with CMC at 50/50 and 25/75 ratios yielded films with phase-separated microparticles. Incorporation of KIAA into the CMC100 carrier resulted in rough and opaque films. The films became more amorphous with the increasing concentration of CMC. Consequently, the higher polysaccharide content was accompanied by lower tensile strength (TS) and elastic modulus (EM). All films with the high concentration of KIAA (60 mg/100g) displayed reduced TS and EM. The control GEL-rich films exhibited significantly lower water vapor permeability (WVP) than the films with the medium- and high-levels of CMC. The KIAA-protein interactions were most likely responsible for the slight decrease in the WVP value of the GEL100 film. In general, an increase in the KIAA concentration resulted in darker yellow-green films with reduced UV/Vis transparency. As expected, the KIAA content in the films decreased over time. Probably due to the high pH, the CMC-rich films exhibited the best ability to stabilize KIAA. The CMC100 films exhibited over 10-fold weaker antiradical potential than the GEL100 films. The highest concentration of KIAA (60 mg/100g) was not an effective dose to cause a significant improvement in the antioxidant potential of all films. The antioxidant activity of the films decreased during storage.

Isolation and screening of stress-resistant endophytic fungus strains from wild and cultivated soybeans in cold region of China.

In this study, we firstly reported the large-scale screening and isolation of endophytic fungi from nine wild and six cultivated soybeans in the cold regions of China. We totally isolated 302 endophytic fungal strains, of which 215 strains are isolated from the wild soybeans and 87 are identified from cultivated soybeans. Among these endophytic fungal strains, in the roots, stems, and leaves, 24.17% were isolated from roots, 28.8% were isolated from stems, and 47.01% were isolated from leaves, respectively. Most endophytic fungal strains isolated from the wild soybean roots were the species of Fusarium genus, and the fungal strains in the stems were the species of ascomycetes and Fusarium fungi, whereas most strains in the leaves were Alternaria fungi. To analyze the taxonomy of the obtained samples, we sequenced and compared their rDNA internal transcribed spacer (ITS) sequences. The data showed that 6 strains are putatively novel strains exhibiting ≤ 97% homology with the known strains. We next measured the secondary metabolites produced by the different strains and we found 11 strains exhibited high-performance synthesis of triterpenoids, phenols, and polysaccharides. Furthermore, we characterized their tolerance to abiotic stresses. The results indicated that 4 strains exhibited high tolerance to cadmium, and some strains exhibited resistance to acid, and alkali. The results of the study could facilitate the further exploration of the diversity of plant endophytic fungi and the potential applications of the fungi to practical agriculture and medicine industries. KEY POINTS: • 302 endophytic fungal strains isolated from wild soybean and cultivated soybean • 11 strains had high contents of triterpenoids, phenols, and polysaccharides • 4 strains exhibited high Cd tolerance, and a few strains with strong tolerance to acid and alkali solution.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ КОМПЛЕКСНОГО УДОБРЕНИЯ «ПОЛИДОН БИО БОБОВЫЙ» НА ПОСЕВАХ КЛЕВЕРА ЛУГОВОГО

The research included the goal of revealing the effect of complex fertilizer on the quantitative composition and classes of microorganisms, as well as the dynamics of the formation of nodule bacteria under clover crops. The experience was laid in the fields of the SKNIIGPSh VNTs RAS. The soil is medium-thick, heavy loamy chernozem, underlain by pebbles. The reaction of the soil solution is slightly acidic (pH-5.73). The humus content is up to 4.5%. The arrangement of variants in repetitions is randomized. The repetition of the experiment is three times. The preparation used is a complex fertilizer with a high content of nitrogen, microelements, amino acids and polysaccharides in the lignosulfonate complex. It was established that the main groups of microorganisms are bacteria (bacilli and non-spore forms) - 6 species, actinomycetes - 2 species and microscopic fungi - 1 species. The soil suspension was sown on meat-peptone, starch-ammonia and wort-agar. When treated with "Polydon Bio Legumes" for clover seedlings at doses of 0.5 l and 1 l/ha, it was found that the best option is 1 l/ha. Compared with the control, the number of non-spore-bearing ammonifiers increased by 2.9 times, bacilli - by 1.8; nitrifiers and actinomycetes - 1.5; microscopic fungi - 2.3 times. In the budding phase - the beginning of flowering, an increase in the dose to 1.5 l / ha had a negative effect on such groups of microorganisms as non-spore-bearing ammonifiers and microscopic fungi. However, the number of bacilli and actinomycetes increased 1.6 times. Therefore, a treatment dose of 1 l/ha is recognized as an effective option. When spraying on seedlings in the variant of 1 l/ha, the first nodules appeared 4-5 days earlier than the control. The introduction of microfertilizers had a positive effect on the quantity - 173 pieces and the weight of the symbiotic apparatus - 94 g. The yield of green mass for 2 cuttings was 317 c/ha, which is 22% higher than the control. This indicator was achieved when treated with Polydon at a dose of 1 l/ha. Increasing the dose of the drug did not affect the yield.

A comprehensive review on oilseed cakes and their potential as a feedstock for integrated biorefinery

In oil processing industry, large number of oilseed cakes remains after the extraction of oil. Oilseed cakes and meals are the residues would act as valuable feeds for livestock as it is rich in protein. These agricultural residues serve as a major valuable feedstock for cattle and used for the production of value-added products such as biogas, biofuel, biopolymer, antibiotics, enzymes, etc. The usage of oilseed cake as raw material would reduce environmental pollution as well as the production cost. This can be served as a potential solution to overcome nutritional problems in animals by enriching the nutrition using appropriate technologies. As the world moving towards sustainable fuel and chemical synthesis using renewable resources deemed as second-generation biofuel feedstock rather than fossil fuels, these non-edible oilseed cakes are used to produce biofuels with an integrated biorefinery perspective. The oilseed cakes plays vital role in the area of enzyme and fermentation technology. The fermentation process using fungi could act as relatively low-cost appropriate technology for upgrading nutrients in oilseed cakes. Oilseed cakes are rich in fibre and have a high concentration of non-starch polysaccharides (NSP) such as cellulose and hemicellulose (Xylan). Lipase and alpha-amylase are the two most essential enzymes produces by the oilseed cake. This review focuses on exploiting the various oilseed cakes and their commercial utilization by implementing various biotechnological approaches.

Mycobacterium tuberculosis Cells Surviving in the Continued Presence of Bactericidal Concentrations of Rifampicin in vitro Develop Negatively Charged Thickened Capsular Outer Layer That Restricts Permeability to the Antibiotic.

Majority of the cells in the bacterial populations exposed to lethal concentrations of antibiotics for prolonged duration succumbs to the antibiotics’ sterilizing activity. The remaining cells survive by diverse mechanisms that include reduced permeability of the antibiotics. However, in the cells surviving in the continued presence of lethal concentrations of antibiotics, it is not known whether any cell surface alterations occur that in turn may reduce permeability of the antibiotics. Here we report the presence of a highly negatively charged, hydrophilic, thickened capsular outer layer (TCOL) on a small proportion of the rifampicin surviving population (RSP) of Mycobacterium tuberculosis (Mtb) cells upon prolonged continuous exposure to bactericidal concentrations of rifampicin in vitro. The TCOL reduced the intracellular entry of 5-carboxyfluorescein-rifampicin (5-FAM-rifampicin), a fluorochrome-conjugated rifampicin permeability probe of negligible bacteriocidal activity but comparable properties. Gentle mechanical removal of the TCOL enabled significant increase in the 5-FAM-rifampicin permeability. Zeta potential measurements of the cells’ surface charge and hexadecane assay for cell surface hydrophobicity showed that the TCOL imparted high negative charge and polar nature to the cells’ surface. Flow cytometry using the MLP and RSP cells, stained with calcofluor white, which specifically binds glucose/mannose units in β (1 → 4) or β (1 → 3) linkages, revealed the presence of lower content of polysaccharides containing such residues in the TCOL. GC-MS analyses of the TCOL and the normal capsular outer layer (NCOL) of MLP cells showed elevated levels of α-D-glucopyranoside, mannose, arabinose, galactose, and their derivatives in the TCOL, indicating the presence of high content of polysaccharides with these residues. We hypothesize that the significantly high thickness and the elevated negative charge of the TCOL might have functioned as a physical barrier restricting the permeability of the relatively non-polar rifampicin. This might have reduced intracellular rifampicin concentration enabling the cells’ survival in the continued presence of high doses of rifampicin. In the context of our earlier report on the de novo emergence of rifampicin-resistant genetic mutants of Mtb from the population surviving under lethal doses of the antibiotic, the present findings attain clinical significance if a subpopulation of the tubercle bacilli in tuberculosis patients possesses TCOL.

Effect of cereal type and plant extract addition on the growth performance, intestinal morphology, caecal microflora, and gut barriers gene expression of broiler chickens

Feeding broiler chickens on diets based on cereal grains of high non-starch polysaccharides content such as wheat and barley can negatively impact their performance and gut health. Plant extracts can be used as a potential tool to alleviate these negative effects. The present study assessed the effects of dietary cereal type and the inclusion of a plant extract blend (PEB) on the growth performance, intestinal histomorphology, caecal microflora, and gene expression of selected biomarkers for gut integrity in broiler chickens in a 42-d experiment. Ross-308 male broilers were assigned into different dietary treatments and fed on two cereal types (corn- vs. wheat/barley-based) with/without added graded concentrations of a PEB (0, 250, 500, 1000, and 2000 mg/kg diet). There were no significant differences in the growth performance parameters, intestinal histomorphology, and caecal microflora due to the impact of dietary cereal type. However, lactobacilli count in the caecal microflora was increased in the group fed on a corn-based diet. The PEB supplementation especially at a level of 500 to 1000 mg/kg diet significantly increased the average BW and decreased the feed conversion ratio. It also increased the villi length of duodenum, jejunum, and ileum, decreased the duodenal crypt depth, and increased the villi length to crypt depth ratio in the duodenum, jejunum and ileum. Supplementation of the PEB decreased the total bacterial and coliform count and increased the lactobacilli count in a linear pattern. Gene expression of Occludin and Junction Adhesion Molecule was significantly increased in the PEB supplemented diets, whereby no influence was observed on mucin expression. In conclusion, supplementation of a PEB at levels of 500–1000 mg/kg can be used as a tool to improve broiler performance and gut health.

Achievement of antioxidants from Abelmoschus esculentus L. seeds using ultrasound-assisted extraction optimized by the help of experimental design approach

Developments of food supplements and nutraceuticals from different natural origins require the use of some extraction methods. The success of the procedure relies on theefficiency of the extraction methods. Therefore, extraction methods need to be optimized. This work aimed for the determination of optimal conditions of ultrasonic-assisted extraction (UAE) of antioxidant constituents from okra (Abelmoschus esculentus L.) seeds which contain high contents of polysaccharides, polyphenols and flavonoids using response-surface methodology based on Box-Behnken experimental design (BBD). The independent variables of UAE were extraction time (Et, 10-20 min), extraction solvent composition (EC, 50-100% methanol) and extraction solvent volume (EV, 10-20 mL). 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, 2,2'-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity and N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) radical-scavenging activity were dependent variables. Optimal extraction conditions for UAE from okra seed were: 20 mL volume of 70% methanol at 10 min extraction time for DPPH inhibition; 20 mL volume of 50% methanol at 20 min for ABTS inhibition; 15 mL volume of 55% methanol at 12 min for DMPD inhibition. Under these optimum extraction conditions, the effectiveness of UAE of okra seed was successfully revealed. So, this practical extraction technique can be widely used for the achievement of dietary supplements and nutraceuticals.

A combined pretreatment with ultrasound-assisted alkaline solution and aqueous deep eutectic solvent for enhancing delignification and enzymatic hydrolysis from oil palm fronds

Oil palm frond (OPF) is one of the most abundant lignocellulosic biomass wastes found in the palm oil industry. However, the recalcitrant nature of OPF makes it hard to produce reducing sugar and convert it into subsequent high-value chemicals. Therefore, OPF was subjected to an ultrasound-assisted NaOH-aqueous deep eutectic solvent (DES) pretreatment in this study to increase delignification and enhance enzymatic saccharification. The effects of ultrasonication on the combined NaOH-aqueous DES for OPF pretreatment and saccharification were scrutinized. Under the recommended ultrasonic pretreatment (amplitude 60 %, duration 30 min) with 2.5 % NaOH-aqueous DES, lignin removal was significantly improved to 47.00 % in comparison to that obtained without ultrasound pretreatment, 30.92 %. OPF subjected to the recommended pretreatment was able to retain a high polysaccharide content, where subsequent enzymatic saccharification was able to achieve a glucose yield of 90.12 %. Physical and chemical characterizations of pretreated OPF were carried out to provide evidence to explain the observed improvement in lignin removal and enzymatic hydrolysis. The use of NaOH-aqueous DES as an ultrasonic medium was proven to be an effective method to promote a novel one-pot, two-processes pretreatment system.

Impact of advanced extraction technologies and characterization of freeze-dried brown seaweed polysaccharides

The main objective of the study is to evaluate the extraction efficiency methods followed by freeze-drying of bioactive brown seaweed polysaccharides (BSPs). Brown seaweeds such as Sargassum wightii, Spatoglossum asperum, Colpomenia sinuosa, Padina tetrastromatica were considered in this study. Conventional solvent extraction (CSE), and advanced extraction techniques such as microwave-aided (MAE), ultrasound-aided (UAE), and enzyme-aided extractions (EAE) were attempted. MAE (2.5 GHz, 15 min) and UAE (50–60 kHz, 30 min) require minimum time and found to be thermal effective compared to the CSE method. EAE exhibited the maximal extraction efficiency of BSPs and S. wightii shown high polysaccharide content (54.99%). The antioxidant activity of all the extracted polysaccharides was evaluated and found to be maximum with P. tetrastromatica. Prebiotic activity assays were attempted on all EAE polysaccharides. Based on antioxidant and prebiotic activity, enzyme-assisted P. tetrastromatica extract was chosen to study for its characteristics using sophisticated analytical techniques. This study signifies the intertwined characteristics of antioxidant properties and shelf life along with its prebiotic activity of freeze-dried bioactive compounds for its desired purpose as a functional ingredient.

Preliminary evaluation of the antimicrobial activity of different Hermetia illucens larvae extracts for application as a cosmetic ingredient

The cosmetic industry is continually searching for innovative ingredients, and there is a current trend in sourcing materials of natural origin. The Hermetia illucens (Linnaeus) larvae biomass is a potential source of compounds with applicability in cosmetics due to its high lipid, protein, and polysaccharide content. High concentrations of lauric acid, also known for also having antimicrobial properties, may be obtained from the lipid fraction. Additionally, these larvae are known to have a well-developed immune system, surviving in decomposition habitats, and can be induced to produce antimicrobial peptides (AMP's). These substances could be probed as alternative preservatives in cosmetics, as consumers are often concerned with the safety of conventional preservatives, such as parabens. The present study conducted a preliminary assessment of the antimicrobial activity of the crude extracts obtained from different extraction methods and extraction solvents against four microorganisms (Gram-positive and negative bacteria and yeasts). The use of diluted extracts did not show relevant inhibition of the growth of the tested microorganisms compared to the positive controls. Further assays are foreseen to test the antimicrobial activity of compounds or fractions isolated from the crude extracts.

English

Girardinia diversifolia (Link) Friis is a perennial herb commonly known as Himalayan giant nettle which belongs to the family Urticaceae. The plant has cultural, medicinal and economic importance. The plant contains high concentration of polysaccharides, polyphenols and secondary metabolites which obstructs the process of isolation of the Deoxyribonucleic Acid (DNA) and inhibits downstream Polymerase Chain Reaction (PCR) amplifications. This study protocol developed a DNA extraction protocol from leaf-tissue based on the Cetyltrimethylammonium bromide, and optimized the PCR protocol for Inter Simple Sequence Repeat (ISSR) analysis. Genomic DNA extraction process was conducted using modified Doyle and Doyle method to obtain good quality DNA. The method yielded 445 ng/µL of DNA, where the purity ranged from 1.8-2.0 indicating minimum contamination of metabolites. The optimum condition for ISSR analysis was established using 4 mM MgCl2 , 0.6 mM dNTPs, 2.0 U Taq polymerase, 50 ng template DNA, and 0.7 µM primer. PCR program was optimized in the sequence of denaturation at 94°C for 3 min, subsequently followed by 45 cycles at 94°C for 30 s, annealing temperature at 45°C for 30 s, extension at 72°C for 2 min, and final extension at 72°C for 10 min. The modified technique was found to be ideal for isolation of genomic DNA and optimization of PCR process for ISSR analysis of G. diversifolia. The results of the research are beneficial for future molecular characterization and genetic diversity analysis of allied taxa. Key words: Girardinia diversifolia, Himalayan nettle, DNA isolation.

Assessment of the effect of autohydrolysis treatment in banana’s pseudostem pulp

Banana’s pseudostem pulp (BPP) is a potential by-product obtained in the mechanical fiber extraction of banana’s pseudostem. Its chemical characterization revealed to have an interesting composition, with a high polysaccharides content and low content in lignin, which makes it particularly relevant for the biorefinery’s biochemical platform. Autohydrolysis pretreatment, studied under isothermal (140 °C) and non-isothermal conditions (140–220 °C), yielded oligosaccharides, mainly gluco-oligosaccharides, as the main soluble products. The highest oligosaccharides production (24 g/100 g raw material) was obtained at a severity factor of 2.3. Autohydrolysis pretreatment effectively disrupted the structure of the material, inducing an improvement of the enzymatic digestibility from 73% for the raw material up to 90% for the most severe conditions. Two stage autohydrolysis, with increasing severity, was also studied, allowing to obtain a higher amount of oligosaccharides (32 g/100 g raw material) and higher digestibility of the remaining solid (up to 97%).

VARIABILITY OF THE CONTENT OF FLAVONOIDS AND POLYSACCHARIDES OF BIDENS CERNUA HERB.

The aim of the research was to study the variability of the content of polysaccharides and flavonoids of Bidens cernua herb, depending on the terms of harvesting, drying conditions and place of growth on the territory of the Republic of Belarus. It was shown that the maximum polysaccharide content was observed in the phase of budding and mass flowering of the plant. Unlike polysaccharides, the content of flavonoids in the budding phase was significantly lower than in the mass flowering phase (p<0.05), which accounts for the maximum content of flavonoids, and in particular, luteolin-7-O-glucoside. The highest polysaccharide content was noted for raw plant materials undergone natural drying or at 40 and 60 °C without ventilation. An increase in the drying temperature or the use of ventilation during drying led to a significant decrease in the content of this group of biologically active substances. The content of flavonoids of Bidens cernua herb, dried at elevated temperature with ventilation, regardless of the drying temperature used, was higher than the content of this group of biologically active substances in comparison with samples of raw plant materials subjected to natural drying (p<0.05). A higher flavonoid content was also noted for Bidens cernua herb, dried without ventilation at 40 and 60 °C. The content of polysaccharides and flavonoids of Bidens cernua herb, depending on the harvesting region, varied between 35.64–90.52 mg/g and 23.11–49.86 mg/g, respectively, and was most dependent on the amount of precipitation per year region. Based on the results obtained, it is recommended to harvest Bidens cernua herb during mass flowering and to dry at 40 °C without ventilation.

The impact of particulate and soluble organic matter on physicochemical properties of extracellular polymeric substances in a microalga Neocystis mucosa SX

Microalgal harvesting is an important link for the integration microalgae-based wastewater treatment with biodiesel production. Extracellular polymAAeric substances (EPS) are considered to be an important factor affecting the flocculation of microalgae. Because the remarkable amount of particulate organic matter exists in real wastewater and is thought to be not readily biodegradable, the effect of particulate organic matter on EPS properties cannot be ignored. Nevertheless, the response of EPS in microalgae to particulate organic matter has still remained unclear. In the study, starch, glucose and sucrose were used to simulate particulate and soluble organic matter to investigate the effect of particulate and soluble organic matter on physicochemical properties of EPS in a microalga Neocystis mucosa SX. The results clearly showed that particulate organic matter significantly promoted the production of EPS, especially extracellular polysaccharides, in the microalga via the cell lysis and the stress induced by available carbon starvation. Compared to notable change on EPS content, the chemical structure and the monomer composition of extracellular polysaccharides did not significantly respond to particulate and soluble organic matter. However, the proportion of functional groups and monomers had a notable response. EPS in the microalga cultivated with particulate organic matter had a lower proportion of some hydrophilic groups C-OH and CO, compared to the microalga cultivated with soluble organic matter. The high content of extracellular polysaccharides and the low proportion of hydrophilic components in EPS as binding sites for the flocculation significantly reduced the flocculation efficiency of the microalga. The results were conducive to reveal the potential mechanism on the response of physicochemical properties of EPS to particulate and soluble organic matter in the process of microalgae-based wastewater treatment, which was essential for microalgal harvesting.

Influence of phenolic acid content on the antioxidant capacity of hemicellulose from sorghum plant fractions

Recovered hemicellulose fractions from biorefineries have the potential to improve overall process economics during the production of biofuels or other high value chemicals. A common hemicellulose found in many agricultural feedstocks is arabinoxylan (AX). This work investigated the influence of ferulic and p-coumaric acids on the antioxidant capability of AX hemicellulose recovered from sorghum bran, biomass, and bagasse. Sorghum bagasse and sorghum biomass AX contained the largest quantities of bound ferulic and p-coumaric acids at 13.1 mg/100 g and 6.3 mg/100 g, respectively. Antioxidant performance showed that sorghum bagasse AX hemicellulose produced the best reducing capability, while sorghum biomass and sorghum bran AX hemicellulose performed better as free radical scavengers. A reduction in free radical scavenging, as determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, occurred for sorghum bagasse and sorghum biomass AX hemicellulose at higher polysaccharide concentrations, which was either caused by the solution properties of the AX hemicelluloses or DPPH reaction reversibility in the presence of phenolic compounds with methoxy content. Alternatively, H2O2 scavenging by the AX hemicellulose revealed a dose-dependent response. Although scavenging effect was reduced at higher concentrations, sorghum bagasse AX hemicellulose functioned as having the best antioxidant capacity with respect to total reducing capability.

Glucose- lowering effect of Trametes orientalis polysaccharides in hyperglycemic and hyperlipidemic mice

To explore the glucose-lowering effect of the polysaccharide fractions of Trametes orientalis. The crude polysaccharides of T. orientalis were chromatographed on DEAE cellulose column using H2O and 0.5 mol/L NaCl solution as the eluent and DEAE-water and DEAE-salt with high polysaccharide contents were collected. The two fractions were separated using Sephadex G-100 gel column to obtain 4 polysaccharide fractions TOPW-1, TOPW-2, TOPS-1, and TOPS-2. The anti-oxidation activity of the polysaccharide fractions was investigated with ABTS method. The fractions TOPW-1 and TOPS-1 with consistent UV detection signals were collected and HPGPC was used to determine their relative molecular mass. The monosaccharide composition in homogeneous TOPW-1 was determined by acid hydrolysis combined with HPLC. The in vitro inhibitory activities of TOPW-1 and TOPS-1 against DPP4, adipocyte glucose intake and lipase activity were tested to preliminarily assess their glucose-lowering effect. In a mouse model of hyperglycemic and hyperlipidemic, the glucose-lowering effect of TOPS-1 (0.1, 0.2, and 0.4 g/kg) and its effect on blood lipid metabolism were investigated in comparison with Xiaoke pills (5 pills/kg) and Danshen tablets (0.5 g/kg). TOPW-1 was a homogeneous polysaccharide composed mainly of D-mannose, D-glucose, D-galactose, and D-fucose, with weak antioxidant and hypoglycemic effects. TOPS-1 was not a single polysaccharide and at the concentration of 500 μg/mL showed an high ABTS clearance rate (90.15%). In the mouse model of hyperglycemia and hyperlipidemia, treatment with TOPS-1 (0.2 g/kg) enhanced the activity of lipase and significantly reduced fasting glucose level and serum contents of total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol without causing death in the mice. The glucose-lowering effects of TOPS-1 was not significant at the low (0.1 g/kg) or high (0.4 g/kg) dose, and a high dose tended to increase the mortality of the mice. T. orientalis polysaccharides have anti-oxidation, glucose-lowering and lipid-lowering effects in mice, and their glucose-lowering effect is probably medicated by reducing oxidative stress and ameliorating lipid metabolism disorder.

Construction and screening of a glycosylphosphatidylinositol protein deletion library in Pichia pastoris

BackgroundGlycosylphosphatidylinositol (GPI)-anchored glycoproteins have diverse intrinsic functions in yeasts, and they also have different uses in vitro. In this study, the functions of potential GPI proteins in Pichia pastoris were explored by gene knockout approaches.ResultsThrough an extensive knockout of GPI proteins in P. pastoris, a single-gene deletion library was constructed for 45 predicted GPI proteins. The knockout of proteins may lead to the activation of a cellular response named the ‘compensatory mechanism’, which is characterized by changes in the content and relationship between cell wall polysaccharides and surface proteins. Among the 45 deletion strains, five showed obvious methanol tolerance, four owned high content of cell wall polysaccharides, and four had a high surface hydrophobicity. Some advantages of these strains as production hosts were revealed. Furthermore, the deletion strains with high surface hydrophobicity were used as hosts to display Candida antarctica lipase B (CALB). The strain gcw22Δ/CALB-GCW61 showed excellent fermentation characteristics, including a faster growth rate and higher hydrolytic activity.ConclusionsThis GPI deletion library has some potential applications for production strains and offers a valuable resource for studying the precise functions of GPI proteins, especially their putative functions.

Sulfated polysaccharide extracted from seaweed Gracilaria caudata attenuates acetic acid-induced ulcerative colitis

Marine macroalgae have high concentrations of sulfated polysaccharides (PLS) studies have demonstrated their antioxidant and anti-inflammatory effects. Certain structural features of PLS such as the formation of sulfate clusters are essential for their biological activities. PLS extracted from Gracilaria caudata have shown therapeutic potential and can be considered an alternative for the treatment of inflammatory bowel disease (IBD) such as ulcerative colitis (UC). The study objective is to evaluate an anti-inflammatory action of Gracilaria caudata PLS on acetic acid-induced intestinal damage in UC model in mice. Mice were treated with PLS from Gracilaria caudata 1.0, 3.0, and 10.0 mg/kg, intraperitoneally (ip) or dexamethasone 2.0 mg/kg, subcutaneously (sc) to determine the best dose of PLS to elicit an anti-inflammatory effect on UC. Colonic-tissue samples were collected for macroscopic analysis, wet weight, microscopic, and biochemical (MPO, GSH, MDA, NO3NO2, cytokine levels and Western blotting for iNOS) features. Treatment with PLS attenuated the colonic inflammatory process during the course of UC by reducing the macroscopic and microscopic scores and reducing the wet weight of the colon. Additionally, there was a reduction in MPO enzyme activity, GSH consumption, and reduction in MDA, NO3/NO2 and pro-inflammatory cytokine (IL-1β and TNF-α) concentrations and reduction in iNOS expression. This study indicates that Gracilaria caudata PLS have anti-inflammatory action on acetic acid-induced UC by reducing inflammatory infiltrate, oxidative stress, pro-inflammatory cytokine action, and iNOS expression. The data suggest that PLS have therapeutic potential against IBD such as UC.