| 1. |
- Zheng, Yuting, et al.
(författare)
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Recent Advances in Bioutilization of Marine Macroalgae Carbohydrates : Degradation, Metabolism, and Fermentation
- 2022
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 70:5, s. 1438-1453
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Tidskriftsartikel (refereegranskat)abstract
- Marine macroalgae are considered renewable natural resources due to their high carbohydrate content, which gives better utilization value in biorefineries and higher value conversion than first- and second-generation biomass. However, due to the diverse composition, complex structure, and rare metabolic pathways of macroalgae polysaccharides, their bioavailability needs to be improved. In recent years, enzymes and pathways related to the degradation and metabolism of macroalgae polysaccharides have been continuously developed, and new microbial fermentation platforms have emerged. Aiming at the bioutilization and transformation of macroalgae resources, this review describes the latest research results from the direction of green degradation, biorefining, and metabolic pathway design, including summarizing the the latest biorefining technology and the fermentation platform design of agarose, alginate, and other polysaccharides. This information will provide new research directions and solutions for the biotransformation and utilization of marine macroalgae.
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| 2. |
- Li, Yanping, et al.
(författare)
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Brown Algae Carbohydrates : Structures, Pharmaceutical Properties, and Research Challenges
- 2021
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Ingår i: Marine Drugs. - : MDPI AG. - 1660-3397. ; 19
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Forskningsöversikt (refereegranskat)abstract
- Brown algae (Phaeophyceae) have been consumed by humans for hundreds of years. Current studies have shown that brown algae are rich sources of bioactive compounds with excellent nutritional value, and are considered functional foods with health benefits. Polysaccharides are the main constituents of brown algae; their diverse structures allow many unique physical and chemical properties that help to moderate a wide range of biological activities, including immunomodulation, antibacterial, antioxidant, prebiotic, antihypertensive, antidiabetic, antitumor, and anticoagulant activities. In this review, we focus on the major polysaccharide components in brown algae: the alginate, laminarin, and fucoidan. We explore how their structure leads to their health benefits, and their application prospects in functional foods and pharmaceuticals. Finally, we summarize the latest developments in applied research on brown algae polysaccharides.
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| 3. |
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| 4. |
- Dan, Meiling, et al.
(författare)
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Current insights of factors interfering the stability of lytic polysaccharide monooxygenases
- 2023
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Ingår i: Biotechnology Advances. - : Elsevier. - 0734-9750 .- 1873-1899. ; 67, s. 108216-108216
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose and chitin are two of the most abundant biopolymers in nature, but they cannot be effectively utilized in industry due to their recalcitrance. This limitation was overcome by the advent of lytic polysaccharide monooxygenases (LPMOs), which promote the disruption of biopolymers through oxidative mechanism and provide a breakthrough in the action of hydrolytic enzymes. In the application of LPMOs to biomass degradation, the key to consistent and effective functioning lies in their stability. The efficient transformation of biomass resources using LPMOs depends on factors that interfere with their stability. This review discussed three aspects that affect LPMO stability: general external factors, structural factors, and factors in the enzyme-substrate reaction. It explains how these factors impact LPMO stability, discusses the resulting effects, and finally presents relevant measures and considerations, including potential resolutions. The review also provides suggestions for the application of LPMOs in polysaccharide degradation.
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| 5. |
- Hsiung, Shih-Yi, et al.
(författare)
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Structures of the xyloglucans in the monocotyledon family Araceae (aroids)
- 2023
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Ingår i: Planta. - : Springer Nature. - 0032-0935 .- 1432-2048. ; 257:2
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Tidskriftsartikel (refereegranskat)abstract
- The aquatic Araceae species Lemna minor was earlier shown to have xyloglucans with a different structure from the fucogalactoxyloglucans of other non-commelinid monocotyledons. We investigated 26 Araceae species (including L. minor), from five of the seven subfamilies. All seven aquatic species examined had xyloglucans that were unusual in having one or two of three features: < 77% XXXG core motif [L. minor (Lemnoideae) and Orontium aquaticum (Orontioideae)]; no fucosylation [L. minor (Lemnoideae), Cryptocoryne aponogetonifolia, and Lagenandra ovata (Aroideae, Rheophytes clade)]; and > 14% oligosaccharide units with S or D side chains [Spirodela polyrhiza and Landoltia punctata (Lemnoideae) and Pistia stratiotes (Aroideae, Dracunculus clade)]. Orontioideae and Lemnoideae are the two most basal subfamilies, with all species being aquatic, and Aroideae is the most derived. Two terrestrial species [Dieffenbachia seguine and Spathicarpa hastifolia (Aroideae, Zantedeschia clade)] also had xyloglucans without fucose indicating this feature was not unique to aquatic species.
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| 6. |
- Kao, Mu-Rong, et al.
(författare)
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Substrate Specificities of Variants of Barley (1,3)- and (1,3;1,4)-β-d-Glucanases Resulting from Mutagenesis and Segment Hybridization
- 2024
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 63:9, s. 1194-1205
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Tidskriftsartikel (refereegranskat)abstract
- Barley (1,3;1,4)-β-d-glucanase is believed to have evolved from an ancestral monocotyledon (1,3)-β-d-glucanase, enabling the hydrolysis of (1,3;1,4)-β-d-glucans in the cell walls of leaves and germinating grains. In the present study, we investigated the substrate specificities of variants of the barley enzymes (1,3;1,4)-β-d-glucan endohydrolase [(1,3;1,4)-β-d-glucanase] isoenzyme EII (HvEII) and (1,3)-β-d-glucan endohydrolase [(1,3)-β-d-glucanase] isoenzyme GII (HvGII) obtained by protein segment hybridization and site-directed mutagenesis. Using protein segment hybridization, we obtained three variants of HvEII in which the substrate specificity was that of a (1,3)-β-d-glucanase and one variant that hydrolyzed both (1,3)-β-d-glucans and (1,3;1,4)-β-d-glucans; the wild-type enzyme hydrolyzed only (1,3;1,4)-β-d-glucans. Using substitutions of specific amino acid residues, we obtained one variant of HvEII that hydrolyzed both substrates. However, neither protein segment hybridization nor substitutions of specific amino acid residues gave variants of HvGII that could hydrolyze (1,3;1,4)-β-d-glucans; the wild-type enzyme hydrolyzed only (1,3)-β-d-glucans. Other HvEII and HvGII variants showed changes in specific activity and their ability to degrade the (1,3;1,4)-β-d-glucans or (1,3)-β-d-glucans to larger oligosaccharides. We also used molecular dynamics simulations to identify amino-acid residues or structural regions of wild-type HvEII and HvGII that interact with (1,3;1,4)-β-d-glucans and (1,3)-β-d-glucans, respectively, and may be responsible for the substrate specificities of the two enzymes.
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| 7. |
- Li, Jing, et al.
(författare)
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Production of Structurally Defined Chito-Oligosaccharides with a Single N-Acetylation at Their Reducing End Using a Newly Discovered Chitinase from Paenibacillus pabuli
- 2021
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society. - 0021-8561 .- 1520-5118. ; 69:11, s. 3371-3379
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Tidskriftsartikel (refereegranskat)abstract
- Partially acetylated chito-oligosaccharides (paCOSs) are bioactive compounds with potential medical applications. Their biological activities are largely dependent on their structural properties, in particular their degree of polymerization (DP) and the position of the acetyl groups along the glycan chain. The production of structurally defined paCOSs in a purified form is highly desirable to better understand the structure/bioactivity relationship of these oligosaccharides. Here, we describe a newly discovered chitinase from Paenibacillus pabuli (PpChi) and demonstrate by mass spectrometry that it essentially produces paCOSs with a DP of three and four that carry a single N-acetylation at their reducing end. We propose that this specific composition of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) residues, as in GlcN(n)GlcNAc1, is due to a subsite specificity toward GlcN residues at the −2, −3, and −4 positions of the partially acetylated chitosan substrates. In addition, the enzyme is stable, as evidenced by its long shelf life, and active over a large temperature range, which is of high interest for potential use in industrial processes. It exhibits a kcatof 67.2 s–1 on partially acetylated chitosan substrates. When PpChi was used in combination with a recently discovered fungal auxilary activity (AA11) oxidase, a sixfold increase in the release of oligosaccharides from the lobster shell was measured. PpChi represents an attractive biocatalyst for the green production of highly valuable paCOSs with a well-defined structure and the expansion of the relatively small library of chito-oligosaccharides currently available.
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| 8. |
- Li, Jing, et al.
(författare)
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Structural analysis and biological activity of cell wall polysaccharides extracted from Panax ginseng marc
- 2019
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 135, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Ginseng marc is a major by-product of the ginseng industry currently used as animal feed or fertilizer. This fibrous, insoluble waste stream is rich in cell wall polysaccharides and therefore a potential source of ingredients for functional food with health-promoting properties. However, the extraction of these polysaccharides has proved problematic and their exact composition remains unknown. Here we have analysed the composition, structure and biological activity of polysaccharides from ginseng root, stem and leaf marc fractionated using a chelator and alkali solutions. The pectic fraction has been extracted from root marc in high abundance and can activate the production of interleukine-1α and the hematopoietic growth factor by RAW 264.7 murine macrophage cells, which are important immune regulators of T-cells during inflammatory responses and infection processes. Our study reveals the potential to increase the value of ginseng marc by generating carbohydrate-based products with a higher value than animal feed.
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| 9. |
- Li, Jing, et al.
(författare)
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Structural compositions and biological activities of cell wall polysaccharides in the rhizome, stem, and leaf of Polygonatum odoratum (Mill.) Druce
- 2022
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 521
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Tidskriftsartikel (refereegranskat)abstract
- Polygonatum odoratum is a perennial rhizomatous medicinal plant and different plant parts have been used in the treatment of various ailments. Herein, we have investigated the structural compositions of rhizome, leaf, and stem cell walls. We found 30–44% of polysaccharides in these wall preparations were cyclohexanediaminetetraacetic acid (CDTA) extractable, the proportion of heteromannans (HMs) in the rhizome is nearly three-fold compared to that of the leave and stem. The pectic polysaccharides of the rhizome are also structurally more diverse, with arabinans and type I and type II arabinogalactans being richest as shown by linkage study of the sodium carbonate (Na2CO3) extract. In addition, the 2-linked Araf was rhizome-specific, suggesting the cell walls in the rhizome had adapted to a more complex structure compared to that of the leaf and stem. Water-soluble polysaccharide fractions were also investigated, high proportion of Man as in 4-linked Manp indicated high proportion of HMs. The 21.4 kDa pectic polysaccharides and HMs derived from rhizome cell walls induced specific immune response in mice macrophage cells producing IL-1α and hematopoietic growth factors GM-CSF and G-CSF in vitro.
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| 10. |
- Wang, Damao, et al.
(författare)
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A colorimetric assay to rapidly determine the activities of lytic polysaccharide monooxygenases
- 2018
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Ingår i: Biotechnology for Biofuels. - : BMC, CAMPUS, 4 CRINAN ST, LONDON N1 9XW, ENGLAND. - 1754-6834. ; 11:215
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Tidskriftsartikel (refereegranskat)abstract
- Lytic polysaccharide monooxygenase (LPMOs) are enzymes that catalyze the breakdown of polysaccharides in biomass and have excellent potential for biorefinery applications. However, their activities are relatively low, and methods to measure these activities are costly, tedious or often reflect only an apparent activity to the polysaccharide substrates. Here, we describe a new method we have developed that is simple to use to determine the activities of type-1 (C1-oxidizing) LPMOs. The method is based on quantifying the ionic binding of cations to carboxyl groups formed by the action of type-1 LPMOs on polysaccharides. It allows comparisons to be made of activities under different conditions.
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