Glycosides Research Articles

Unveiling the Dissolution Regularities of the Lignin-Carbohydrate Complex in Bamboo Cell Walls during Alkali Pretreatment.

Bamboo is a promising biomass resource. However, the complex multilayered structure and chemical composition of bamboo cell walls create a unique anti-depolymerization barrier, which increases the difficulty of separation and utilization of bamboo. In this study, the relationship between the connections of lignin-carbohydrate complexes (LCCs) within bamboo cell walls and their multilayered structural compositions was investigated. The chemical composition, structural properties, dissolution processes, and migration mechanisms of LCCs were analyzed. Alkali-stabilized LCC bonds were found to be predominantly characterized by phenyl glycoside (PhGlc) bonds along with numerous p-coumaric acid (PCA) linkage structures. As demonstrated by the NMR and CLSM results, the dissolution of the LCC during the alkaline pretreatment process was observed to migrate from the inner secondary wall (S-layer) of the bamboo fiber cell walls to the cell corner middle lamella (CCML) and compound middle lamella (CML), ultimately leading to its release from the bamboo. Furthermore, the presence of H-type lignin-FA-arabinoxylan linkage structures within the bamboo LCC was identified with their primary dissolution observed in the S-layer of the bamboo fiber cell walls. The study results provided a clear target for breaking down the anti-depolymerization barrier in bamboo, signifying a major advancement in achieving the comprehensive separation of bamboo components.

Evaluation of free radical‐induced structural changes and their effect on antioxidant and anti‐inflammatory activities of UV/H2O2‐degraded dextrans

AbstractAlthough ultraviolet (UV)/H2O2 treatment could effectively improve the bioactivities of polysaccharides, the relationship between free radical‐induced structural changes and the bioactivities of products remains unknown. Therefore, this work investigated the changes in the chemical characteristics and chain conformations of degraded dextrans by the UV/H2O2 system as well as their antioxidant and anti‐inflammatory activities. The apparent degradation efficiencies of dextrans under different UV/H2O2 parameters were first investigated. UV/H2O2 treatment effectively destroyed the pyranose rings and glycosidic bonds of dextrans and significantly improved their uronic acid and carboxy contents. Furthermore, conformational studies revealed that besides the rapid decrease in the molecular weight, the compact spherical conformation of dextrans was gradually depolymerized into the flexible random coil conformation. Moreover, the significant antioxidant and anti‐inflammatory activities of the degraded dextrans were mainly attributed to their more extended random coil chains, increased quantity of reducing groups, and lower molecular sizes. This study contributes to investigating the structure–activity relationship of polysaccharides prepared by free radicals‐mediated degradation.

In vitro digestion properties of Laiyang pear residue polysaccharides and it counteracts DSS-induced gut injury in mice via modulating gut inflammation, gut microbiota and intestinal barrier

The aim of this study was to explore the dynamic changes in the physicochemical properties of Laiyang pear residue polysaccharide (LPP) during in vitro digestion, as well as its protective effect on the intestines. Monosaccharide composition and molecular weight analysis showed that there was no significant change in LPP during the oral digestion stage. However, during the gastric and intestinal digestion stages, the glycosidic bonds of LPP were broken, leading to the dissociation of large molecular aggregates and a significant increase in reducing sugar content (CR) accompanied by a decrease in molecular weight. In addition, LPP exerted the intestinal protective ability via inhibiting gut inflammation, improving intestinal barrier, and regulating intestinal flora in DSS-induced mice. Specifically, LPP mitigated DSS-induced intestinal pathological damage of mice via enhancing intestinal barrier integrity and upregulating expressions of TJ proteins, and suppressed inflammation by inhibiting NF-κB signaling axis. Furthermore, LPP decreased the ratio of Firmicutes/Bacteroidetes, increased the relative abundance of Lactobacillus, and altered the diversity and the composition of gut microbiota in DSS-induced mice. Therefore, LPP had the potential to be a functional food that improved gut microbiota environment to enhance health and prevent diseases, such as a prebiotic.

Bottom-Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis.

Linear d-glucans are natural polysaccharides of simple chemical structure. They are comprised of d-glucosyl units linked by a single type of glycosidic bond. Noncovalent interactions within, and between, the d-glucan chains give rise to a broad variety of macromolecular nanostructures that can assemble into crystalline-organized materials of tunable morphology. Structure design and functionalization of d-glucans for diverse material applications largely relies on top-down processing and chemical derivatization of naturally derived starting materials. The top-down approach encounters critical limitations in efficiency, selectivity, and flexibility. Bottom-up approaches of d-glucan synthesis offer different, and often more precise, ways of polymer structure control and provide means of functional diversification widely inaccessible to top-down routes of polysaccharide material processing. Here the natural and engineered enzymes (glycosyltransferases, glycoside hydrolases and phosphorylases, glycosynthases) for d-glucan polymerization are described and the use of applied biocatalysis for the bottom-up assembly of specific d-glucan structures is shown. Advanced material applications of the resulting polymeric products are further shown and their important role in the development of sustainable macromolecular materials in a bio-based circular economy is discussed.

Synthesis of 4'-Thionucleoside Analogues Bearing a C2' Stereogenic All-Carbon Quaternary Center.

The design of novel 4'-thionucleoside analogues bearing a C2' stereogenic all-carbon quaternary center is described. The synthesis involves a highly diastereoselective Mukaiyama aldol reaction, and a diastereoselective radical-based vinyl group transfer to generate the all-carbon stereogenic C2' center, along with different approaches to control the selectivity of the N-glycosidic bond. Intramolecular SN2-like cyclization of a mixture of acyclic thioaminals provided analogues with a pyrimidine nucleobase. A kinetic bias favoring cyclization of the 1',2'-anti thioaminal furnished the desired β-D-4'-thionucleoside analogue in a 7:1 ratio. DFT calculations suggest that this kinetic resolution originates from additional steric clash in the SN2-like transition state for 1',4'-trans isomers, causing a significant decrease in their reaction rate relative to 1',4'-cis counterparts. N-glycosylation of cyclic glycosyl donors with a purine nucleobase enabled the formation of novel 2-chloroadenine 4'-thionucleoside analogues. These proprietary molecules and other derivatives are currently being evaluated both in vitro and in vivo to establish their biological profiles.

Multifaceted roles of plant glycosyl hydrolases during pathogen infections: more to discover.

Carbohydrates are hydrolyzed by a family of carbohydrate-active enzymes (CAZymes) called glycosidases or glycosyl hydrolases. Here, we have summarized the roles of various plant defense glycosidases that possess different substrate specificities. We have also highlighted the open questions in this research field. Glycosidases or glycosyl hydrolases (GHs) are a family of carbohydrate-active enzymes (CAZymes) that hydrolyze glycosidic bonds in carbohydrates and glycoconjugates. Compared to those of all other sequenced organisms, plant genomes contain a remarkable diversity of glycosidases. Plant glycosidases exhibit activities on various substrates and have been shown to play important roles during pathogen infections. Plant glycosidases from different GH families have been shown to act upon pathogen components, host cell walls, host apoplastic sugars, host secondary metabolites, and host N-glycans to mediate immunity against invading pathogens. We could classify the activities of these plant defense GHs under eleven different mechanisms through which they operate during pathogen infections. Here, we have provided comprehensive information on the catalytic activities, GH family classification, subcellular localization, domain structure, functional roles, and microbial strategies to regulate the activities of defense-related plant GHs. We have also emphasized the research gaps and potential investigations needed to advance this topic of research.

Development of Non-toxic Recombinant Ricin Vaccine and Evaluation of Vaccine Efficacy

Ricin is a highly toxic protein which is produced in the seeds of the castor oil plant. Ricin toxin A chain has ribosomal RNA N-glycosylase activity that irreversibly hydrolyses the N-glycosidic bond of the adenine residue at position 4324 within the 28S rRNA. In this study, we developed non-toxic recombinant ricin vaccine(R51) in <i>E. coli</i> expression system, and evaluated efficacy of the R51 according to adjuvants. When the R51 was administered using aluminum hydroxide as an adjuvant, the vaccine efficacy was higher than that of TLR agonists or aluminum phosphate. Because it is time-consuming to administer the vaccine three times at three-week intervals, we investigated the survival rate and antibody titer of mice according to the change of time interval of vaccination. Interestingly, there was no difference in survival rate and antibody titer when R51 was administered at 0, 1, and 3 weeks or 0, 2, and 4 weeks compared to when administered at 0, 3, and 6 weeks. Therefore, the developed R51 vaccine is promising to protect soldiers from Ricin attack.

Updated Progress on Polysaccharides with Anti-Diabetic Effects through the Regulation of Gut Microbiota: Sources, Mechanisms, and Structure-Activity Relationships.

Diabetes mellitus (DM) is a common chronic metabolic disease worldwide. The disturbance of the gut microbiota has a complex influence on the development of DM. Polysaccharides are one type of the most important natural components with anti-diabetic effects. Gut microbiota can participate in the fermentation of polysaccharides, and through this, polysaccharides regulate the gut microbiota and improve DM. This review begins by a summary of the sources, anti-diabetic effects and the gut microbiota regulation functions of natural polysaccharides. Then, the mechanisms of polysaccharides in regulating the gut microbiota to exert anti-diabetic effects and the structure-activity relationship are summarized. It is found that polysaccharides from plants, fungi, and marine organisms show great hypoglycemic activities and the gut microbiota regulation functions. The mechanisms mainly include repairing the gut burrier, reshaping gut microbiota composition, changing the metabolites, regulating anti-inflammatory activity and immune function, and regulating the signal pathways. Structural characteristics of polysaccharides, such as monosaccharide composition, molecular weight, and type of glycosidic linkage, show great influence on the anti-diabetic activity of polysaccharides. This review provides a reference for the exploration and development of the anti-diabetic effects of polysaccharides.

Organocatalyzed Stereoselective Glycosylation: An Overview of the Last Decade

Abstract: Even though there has been an important evolution in the synthesis of oligosaccharides, the efficient and stereoselective study of glycosidic bonds through non-toxic, moderate, and inexpensive techniques is one of the most challenging fields in organic synthesis. Glycosyl reactions play a fundamental role in biological material and structure-activity relationships, having numerous medicinal chemistry applications. For this, interesting strategies have evolved over the years to control the stereoselectivity of glycosidic bonds, including the manipulation of different reaction elements, mainly promoters or catalysts, but also involving the nature of donors and solvents. This review looks at glycosylation methodologies in the last decade resulting in the specific formation of alpha or beta glycosidic bonds.

Structural Characterization and Immunological Activity of Polysaccharide Degradation Products from Phlebopus portentosus

Phlebopus portentosus is an edible and medicinal mushroom with a delicious taste and high nutritional value. The oligosaccharides derived from P. portentosus may be the material basis for its biological activity. The degradation of polysaccharide and the maintenance of its activity after degradation are key steps in related research. This study applied an acid degradation method to prepare P. portentosus refined polysaccharide (PPRP) with a smaller molecular weight, and the optimal hydrolysis conditions determined were a temperature of 80 °C, an acid concentration of 2 mol/L, and a hydrolysis time of 2 h. The polysaccharide structure and immune activity were then further investigated. The results showed that the PPRP comprised two fractions with approximate weights of 61,600 Da and 5500 Da. The monosaccharide composition of PPRP was mannose, rhamnose, glucose, and galactose, with a molar ratio of 1.00: 22.24: 2.93: 1.03. The major functional groups included O-H, C-H, C-O, and C-O-C. The glycosidic bond types were mainly α- and β-glycosidic bonds. Cell experiments demonstrated that PPRP could significantly increase the proliferation of macrophages and enhance the cytotoxicity of NK cells. Moreover, PPRP also significantly promoted the proliferation of B lymphocytes and T lymphocytes, especially at a concentration of 200 μg/mL. This study furnishes scientific evidence underlining the significant potential of PPRP in immune activity, thereby serving as a material basis and scientific bedrock for further investigations into the mechanism of P. portentosus oligosaccharide activity.

Isolation and molecular characterization of cellulase-producing bacteria from waste dump site

Cellulases are collections of extracellular enzymes and a complex mixture of enzyme proteins with various specificities. Cellulases work together to hydrolyze glycosidic bonds and generate monomers of glucose for fermentation. This investigation aims to isolate and molecularly characterize Bacillus species with cellulolytic ability. Bacillus species were isolated from soil samples retrieved from a dump site and screened for cellulolytic ability on carboxyl methylcellulose (CMC) agar. The percentage hydrolysis efficiency of isolates was determined and cellulase produced was quantified using CMC assay method. Biochemical identification was by Analytical Profile Index (API) Kit 50CHB/20E and API web software while molecular characterization employed 16S rRNA gene sequencing and blast search analysis. Bacillus megaterium (FSP1) and Bacillus zanthoxyli (FSP4) exhibited their cellulolytic potentials by presenting zones of clearance of about 21 ± 2.08 and 7 ± 1.00 mm on CMCA with hydrolysis efficiency of 250 and 600 % respectively. Quantification of crude cellulase revealed cellulase activity of 85 and 74μmol/ml for both bacteria species. Biochemically, the cellulolytic bacteria were identified as Bacillus megaterium (FSP1) and Bacillus zanthoxyli (FSP4) while molecularly, they were identified as Bacillus megaterium 14581 (FSP1) and Bacillus zanthoxyli 1433 (FSP4) with Reference Sequence (RefSeq) accession numbers NR_116873 and NR_164882, and showing maximum sequence similarity of 99 and 96 % respectively. Results obtained from this investigation, suggests that both bacteria species characterised, possesses good cellulolytic ability and hence can be utilized for the production of the enzyme cellulase which has a wide range of industrial application.

In vitro batch fermentation demonstrates variations in the regulation of gut microbiota and metabolic functions by β-glucans of differing structures

The gut microbiota is widely acknowledged as a crucial factor in regulating host health. The structure of dietary fibers determines changes in the gut microbiota and metabolic differences resulting from their fermentation, which in turn affect gut microbe-related health effects. β-Glucan (BG) is a widely accessible dietary fiber to humans, and its structural characteristics vary depending on the source. However, the interactions between different structural BGs and gut microbiota remain unclear. This study used an in vitro fermentation model to investigate the effects of BG on gut microbiota, and microbiomics and metabolomics techniques to explore the relationship between the structure of BG, bacterial communities, and metabolic profiles. The four sources of BG (barley, yeast, algae, and microbial fermentation) contained different types and proportions of glycosidic bonds, which differentially altered the bacterial community. The BG from algal sources, which contained only β(1 → 4) glycosidic bonds, was the least metabolized by the gut microbiota and caused limited metabolic changes. The other three BGs contain more diverse glycosidic bonds and can be degraded by bacteria from multiple genera, causing a wider range of metabolic changes. This work also suggested potential synergistic degradation relationships between gut bacteria based on BG. Overall, this study deepens the structural characterization-microbial-functional understanding of BGs and provides theoretical support for the development of gut microbiota-targeted foods.

The structural characterization of a novel Chinese yam polysaccharide and its hypolipidemic activity in HFD-induced obese C57BL/6J mice

Obesity was considered as a rapidly growing chronic disease that influences human health worldwide. In this study, we investigated the primary structure characteristics of Chinese yam polysaccharide (CYP) and its role in regulating lipid metabolism in a high-fat diet (HFD)-fed obese mice. The molecular weight of CYP was determined to be 3.16 × 103 kDa. Periodic acid oxidation & smith degradation and nuclear magnetic resonance results suggested that CYP consists of 1 → 2, 1 → 2, 6, 1 → 4, 1 → 4, 6, 1→, or 1 → 6 glycoside bonds. The in vivo experiment results suggested that the biochemical indices, tissue sections, and protein regulation associated with lipid metabolism were changed after administering CYP in obese mice. In addition, the abundances of short-chain fatty acid (SCFA)-producing bacteria Lachnospiraceae, Lachnospiraceae_NK4A136_group, and Ruminococcaceae_UCG-014 were increased, and the abundances of bacteria Desulfovibrionaceae and Ruminococcus and metabolites of arginine, propionylcarnitine, and alloisoleucine were decreased after CYP intervention in obese mice. Spearman's correlation analysis of intestinal flora, metabolites, and lipid metabolism parameters showed that CYP may affect lipid metabolism in obese mice by regulating the intestinal environment. Therefore, CYP may be used as a promising nutritional intervention agent for lipid metabolism.

In sight the behavior of natural Bletilla striata polysaccharide hydrocolloids by molecular dynamics method

Plant polysaccharides, distinguished by diverse glycosidic bonds and various cyclic sugar units, constitute a subclass of primary metabolites ubiquitously found in nature. Contrary to common understanding, plant polysaccharides typically form hydrocolloids upon dissolution in water, even though both excessively high and low temperatures impede this process. Bletilla striata polysaccharides (BSP), chosen for this kinetic study due to their regular repeating units, help elucidate the relationship between polysaccharide gelation and temperature. It is suggested that elevated temperatures enhance the mobility of BSP molecular chains, resulting in a notable acceleration of hydrogen bond breakage between BSP and water molecules and consequently, compromising the conformational stability of BSPs to some extent. This study unveils the unique relationship between polysaccharide dissolution processes and temperature from a kinetics perspective. Consequently, the conclusion provides a dynamical basis for comprehending the extraction and preparation of natural plant polysaccharide hydrocolloids, pharmaceuticals and related fields.

The 4K reaction

The classical Koenigs-Knorr glycosidation of bromides or chlorides promoted with Ag2O or Ag2CO3 works only with reactive substrates (ideally both donor and acceptor). This reaction was found to be practically ineffective with unreactive donors such as per-O-benzoylated mannosyl bromide. Recently, it was discovered that the addition of catalytic (Lewis) acids to a silver salt-promoted reaction has a dramatic effect on the reaction rate and yield. A tentative mechanism for this cooperatively-catalyzed glycosylation reaction has been proposed, and the improved understanding of the reaction led to more efficient protocols and broader applications to a variety of glycosidic linkages. Since Ag2O-mediated activation was introduced by German chemists Koenigs and Knorr, and “cooperatively catalyzed” is Kooperativ Katalysiert in German, we refer to this new reaction as “the 4K reaction.”

A trapped covalent intermediate as a key catalytic element in the hydrolysis of a GH3 β-glucosidase: An X-ray crystallographic and biochemical study

Glycoside hydrolases (GHs) are industrially important enzymes that hydrolyze glycosidic bonds in glycoconjugates. In this study, we found a GH3 β-glucosidase (CcBgl3B) from Cellulosimicrobium cellulans sp. 21 was able to selectively hydrolyze the β-1,6-glucosidic bond linked glucose of ginsenosides. X-ray crystallographic studies of the ligand complex ginsenoside-specific β-glucosidase provided a novel finding that support the catalytic mechanism of GH3. The substrate was clearly identified within the catalytic center of wild-type CcBgl3B, revealing that the C1 atom of the glucose was covalently bound to the Oδ1 group of the conserved catalytic nucleophile Asp264 as an enzyme–glycosyl intermediate. The glycosylated Asp264 could be identified by mass spectrometry. Through site-directed mutagenesis studies with Asp264, it was found that the covalent intermediate state formed by Asp264 and the substrate was critical for catalysis. In addition, Glu525 variants (E525A, E525Q and E525D) showed no or marginal activity against pNPβGlc; thus, this residue could supply a proton for the reaction. Overall, our study provides an insight into the catalytic mechanism of the GH3 enzyme CcBgl3B.

Biochemical and in silico structural properties of a thermo-acid stable β-glucosidase from Beauveria bassiana

β-glucosidase hydrolyses the glycosidic bonds in cellobiose and cello-oligosaccharides, a critical step in the saccharification for biofuel production. Hence, the aim of this study was to gain insights into the biochemical and structural properties of a β-glucosidase from Beauveria bassiana, an entomopathogenic fungus. The β-glucosidase was purified to homogeneity using salt precipitation, ultrafiltration, and chromatographic techniques, attaining a specific activity of 496 U/mg. The molecular mass of the enzyme was then estimated via SDS-PAGE to be 116 kDa, while its activity pattern was confirmed by zymography using 4-methylumbelliferyl-β-d-glucopyranoside. Furthermore, the pH optima and temperature of the enzyme were found to be pH 5.0 and 60 °C respectively; its activity was significantly enhanced by Mg2+ and Na+ and was found to be relatively moderate in the presence of ethanol and dichloromethane. Molecular docking of the modelled B. bassiana β-glucosidase structure with the substrates, viz., 4-nitrophenyl β-d-glucopyranoside and cellobiose, revealed the binding affinity energies of −7.2 and −6.2 (kcal mol−1), respectively. Furthermore, the computational study predicted Lys-657, Asp-658, and Arg-1000 as the core amino acid residues in the catalytic site of the enzyme. This is the first investigation into a purified β-glucosidase from B. bassiana, providing valuable insights into the functional properties of carbohydrases from entomopathogenic fungal endophytes.

Ultrasound Assisted Aqueous Two‐Phase Extraction of Polysaccharides from Ophiopogon japonicus: Process Optimization, Structure Characterization, and Antioxidant Activity

AbstractUltrasound assisted aqueous two‐phase extraction (UATPE) is used to extract polysaccharides from Ophiopogon japonicus (OJPs). Experimental factors in UATPE process are optimized by response surface methodology. The optimal extraction conditions are obtained as follows: the ethanol concentration of 34%, ammonium sulfate concentration of 23%, solid‐to‐liquid ratio of 1:17 g/mL, and ultrasound power of 480 W, and the yield of OJPs is 9.41% ± 0.12%, and then the crude OJPs are further purified by different column chromatography to obtain a homogenous fraction (OJPs‐2‐SG), and identified its structure via different methods. OJPs‐2‐SG with a molecular weight of 1.25 × 105 Da is comprised of mannose (Man), galactose (Gal), glucose (Glc), and rhamnose (Rha) with a molar ratio of 5.15: 26.39: 68.72:8.41. Moreover, OJPs‐2‐SG contained α and β glycosidic bonds, and didn't showed a triple helix structure. Furthermore, OJPs‐2‐SG described irregular structures, and cylindrical and conical block like features. The IC50 values of scavenging 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), hydroxyl (OH), and superoxide (O2‐) radicals for OJPs‐2‐SG achieved 3.72 mg/mL, 3.89 mg/mL, and 8.71 mg/mL, respectively. These results provide important references for the extraction and application of polysaccharides.

Mitigating salinity stress through interactions between microalgae and different forms (free-living & alginate gel-encapsulated) of bacteria isolated from estuarine environments

Salinity stress in estuarine environments poses a significant challenge for microalgal survival and proliferation. The interaction between microalgae and bacteria shows promise in alleviating the detrimental impacts of salinity stress on microalgae. Our study investigates this interaction by co-cultivating Chlorella sorokiniana, a freshwater microalga, with a marine growth-promoting bacterium Pseudomonas gessardii, both of which were isolated from estuary. In this study, bacteria were encapsulated using sodium alginate microspheres to establish an isolated co-culture system, preventing direct exposure between microalgae and bacteria. We evaluated microalgal responses to different salinities (5 PSU, 15 PSU) and interaction modes (free-living, gel-encapsulated), focusing on growth, photosynthesis, cellular metabolism, and extracellular polymeric substances (EPS) properties. High salinity inhibited microalgal proliferation, while gel-fixed interaction boosted Chlorella growth rate by 50.7 %. Both attached and free-living bacteria restored Chlorella's NPQ to normal levels under salt stress. Microalgae in the free-living interaction group exhibited a significantly lower respiratory rate compared to the pure algae group (−17.2 %). Increased salinity led to enhanced EPS polysaccharide secretion by microalgae, particularly in interaction groups (19.7 %). Both salt stress and interaction increased the proportion of aromatic proteins in microalgae's EPS, enhancing its stability by modulating EPS glycosidic bond C-O-C and protein vibrations. This alteration caused microalgal cells to aggregate, free-living bacteria co-culture group, and fixed co-culture group increasing by 427.5 %, 567.1 %, and 704.1 %, respectively. In gel-fixed bacteria groups, reduced neutral lipids don't accumulate starch instead, carbon redirects to cellular growth, aiding salt stress mitigation. These synergistic activities between salinity and bacterial interactions are vital in mitigating salinity stress, improving the resilience and growth of microalgae in saline conditions. Our research sheds light on the mechanisms of microalgal-bacterial interactions in coping with salt stress, offering insights into the response of estuarine microorganisms to global environmental changes and their ecological stability.

Effects of radiation dose and dose rate on alginate and the use of radiation degraded alginate for peanut

Aqueous solutions of alginate (4 %) with or without hydrogen peroxide (0–2 % H2O2) were irradiated under a gamma Co-60 source. The effect of dose rate on the radiation scission yield (Gs) of resulting irradiated alginate was determined. At the dose of 20 kGy, the G(s) value of irradiated alginate decreased with the increase dose rate, suggesting that the irradiation at a suitable dose rate could further improve the radiation chemical yield of degradation. For the alginate irradiated at the same dose rate, G(s) value increased with the increase of H2O2 concentration. Average molecular weight (Mw) and polydispersity index (PI) of irradiated alginate rapidly decreased with the increase in dose and further decreased by addition of H2O2. The oligoalginate with Mw ~ 9800 g/mol was obtained by radiation degradation of 4 % alginate solution containing 2 % H2O2 at dose of 20 kGy. Radiation scission of glycoside bonds and formation of carbonyl groups (C=O) were indicated in UV and FTIR spectra of irradiated alginate. Peanut seedlings were fertilized with alginate and oligoalginate solutions, and the results showed that all growth parameters of the treated plants were better than those of the control. Furthermore, the oligoalginate prepared by gamma irradiation can be applied as a plant growth promoter for agriculture production.