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Berezina OV, Rykov SV, Schwarz WH, Liebl W. Xanthan: enzymatic degradation and novel perspectives of applications. Appl Microbiol Biotechnol 2024; 108:227. [PMID: 38381223 PMCID: PMC10881899 DOI: 10.1007/s00253-024-13016-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 02/22/2024]
Abstract
The extracellular heteropolysaccharide xanthan, synthesized by bacteria of the genus Xanthomonas, is widely used as a thickening and stabilizing agent across the food, cosmetic, and pharmaceutical sectors. Expanding the scope of its application, current efforts target the use of xanthan to develop innovative functional materials and products, such as edible films, eco-friendly oil surfactants, and biocompatible composites for tissue engineering. Xanthan-derived oligosaccharides are useful as nutritional supplements and plant defense elicitors. Development and processing of such new functional materials and products often necessitate tuning of xanthan properties through targeted structural modification. This task can be effectively carried out with the help of xanthan-specific enzymes. However, the complex molecular structure and intricate conformational behavior of xanthan create problems with its enzymatic hydrolysis or modification. This review summarizes and analyzes data concerning xanthan-degrading enzymes originating from microorganisms and microbial consortia, with a particular focus on the dependence of enzymatic activity on the structure and conformation of xanthan. Through a comparative study of xanthan-degrading pathways found within various bacterial classes, different microbial enzyme systems for xanthan utilization have been identified. The characterization of these new enzymes opens new perspectives for modifying xanthan structure and developing innovative xanthan-based applications. KEY POINTS: • The structure and conformation of xanthan affect enzymatic degradation. • Microorganisms use diverse multienzyme systems for xanthan degradation. • Xanthan-specific enzymes can be used to develop xanthan variants for novel applications.
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Affiliation(s)
- Oksana V Berezina
- National Research Centre «Kurchatov Institute», Academician Kurchatov Sq. 1, 123182, Moscow, Russian Federation
| | - Sergey V Rykov
- National Research Centre «Kurchatov Institute», Academician Kurchatov Sq. 1, 123182, Moscow, Russian Federation
| | - Wolfgang H Schwarz
- Chair of Microbiology, Technical University of Munich, TUM School of Life Sciences, Emil-Ramann-Str. 4, 85354, Freising, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, TUM School of Life Sciences, Emil-Ramann-Str. 4, 85354, Freising, Germany.
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Xanthan gum in aqueous solutions: Fundamentals and applications. Int J Biol Macromol 2022; 216:583-604. [DOI: 10.1016/j.ijbiomac.2022.06.189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 11/24/2022]
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Effects of photo-stimulation with laser or LED on the composition of Xanthan gum produced in media containing distilled water or dialyzed or not produced water by means of Raman spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 213:112057. [DOI: 10.1016/j.jphotobiol.2020.112057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/07/2020] [Accepted: 10/15/2020] [Indexed: 12/29/2022]
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4
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Sampaio IC, Crugeira PJ, Soares LG, dos Santos JN, de Almeida PF, Pinheiro AL, Silveira L. Composition of Xanthan gum produced by Xanthomonas campestris using produced water from a carbonated oil field through Raman spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 213:112052. [DOI: 10.1016/j.jphotobiol.2020.112052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/16/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
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In-depth rheological characterization of genetically modified xanthan-variants. Carbohydr Polym 2019; 213:236-246. [DOI: 10.1016/j.carbpol.2019.02.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/15/2019] [Accepted: 02/16/2019] [Indexed: 11/19/2022]
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Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11. Appl Environ Microbiol 2019; 85:AEM.01800-18. [PMID: 30413476 DOI: 10.1128/aem.01800-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/27/2018] [Indexed: 11/20/2022] Open
Abstract
Under general aqueous conditions, xanthan appears in an ordered conformation, which makes its backbone largely resistant to degradation by known cellulases. Therefore, the xanthan degradation mechanism is still unclear because of the lack of an efficient hydrolase. Here, we report the catalytic properties of MiXen, a xanthan-degrading enzyme identified from the genus Microbacterium MiXen is a 952-amino-acid protein that is unique to strain XT11. Both the sequence and structural features suggested that MiXen belongs to a new branch of the GH9 family and has a multimodular structure in which a catalytic (α/α)6 barrel is flanked by an N-terminal Ig-like domain and by a C-terminal domain that has very few homologues in sequence databases and functions as a carbohydrate-binding module (CBM). Based on circular dichroism, shear-dependent viscosity, and reducing sugar and gel permeation chromatography analysis, we demonstrated that recombinant MiXen efficiently and randomly cleaved glucosidic bonds within the highly ordered xanthan substrate. A MiXen mutant free of the C-terminal CBM domain partially lost its xanthan-hydrolyzing ability because of decreased affinity toward xanthan, indicating the CBM domain assisted MiXen in hydrolyzing highly ordered xanthan via recognizing and binding to the substrate. Furthermore, side chain substituents and the terminal mannosyl residue significantly influenced the activity of MiXen via the formation of barriers to enzymolysis. Overall, the results of this study provide insight into the hydrolysis mechanism and enzymatic properties of a novel endotype xanthanase that will benefit future applications.IMPORTANCE This work characterized a novel endotype xanthanase, MiXen, and elucidated that the C-terminal carbohydrate-binding module of MiXen could drastically enhance the hydrolysis activity of the enzyme toward highly ordered xanthan. Both the sequence and structural analysis demonstrated that the catalytic domain and carbohydrate-binding module of MiXen belong to the novel branch of the GH9 family and CBMs, respectively. This xanthan cleaver can help further reveal the enzymolysis mechanism of xanthan and provide an efficient tool for the production of molecular modified xanthan with new physicochemical and physiological functions.
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Takemasa M, Nishinari K. Solution Structure of Molecular Associations Investigated Using NMR for Polysaccharides: Xanthan/Galactomannan Mixtures. J Phys Chem B 2016; 120:3027-37. [DOI: 10.1021/acs.jpcb.5b11665] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Makoto Takemasa
- School
of Creative Science and Engineering, Waseda University, Tokyo, Japan
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Production and purification of a novel xanthan lyase from a xanthan-degrading Microbacterium sp. strain XT11. ScientificWorldJournal 2014; 2014:368434. [PMID: 25054177 PMCID: PMC4099120 DOI: 10.1155/2014/368434] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 06/02/2014] [Accepted: 06/04/2014] [Indexed: 11/18/2022] Open
Abstract
A xanthan lyase was produced and purified from the culture supernatant of an excellent xanthan-modifying strain Microbacterium sp. XT11. Xanthan lyase was induced by xanthan but was inhibited by its structural monomer glucose. Its production by strain XT11 is much higher than that by all other reported strains. The purified xanthan lyase has a molecular mass of 110 kDa and a specific activity of 28.2 U/mg that was much higher than that of both Paenibacillus and Bacillus lyases. It was specific on the pyruvated mannosyl residue in the intact xanthan molecule, but about 50% lyase activity remained when xanthan was partially depyruvated. Xanthan lyase was optimally active at pH 6.0–6.5 and 40°C and alkali-tolerant at a high pH value of 11.0. The metal ions including K+, Ca2+, Na+, Mg2+, Mn2+, and Li+ strongly stimulated xanthan lyase activity but ions Zn2+ and Cu2+ were its inhibitor. Xanthan lyase should be a novel enzyme different from the other xanthan lyases ever reported.
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11
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Kool MM, Gruppen H, Sworn G, Schols HA. The influence of the six constituent xanthan repeating units on the order–disorder transition of xanthan. Carbohydr Polym 2014; 104:94-100. [DOI: 10.1016/j.carbpol.2013.12.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/23/2013] [Accepted: 12/25/2013] [Indexed: 10/25/2022]
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Roy A, Comesse S, Grisel M, Hucher N, Souguir Z, Renou F. Hydrophobically Modified Xanthan: An Amphiphilic but Not Associative Polymer. Biomacromolecules 2014; 15:1160-70. [DOI: 10.1021/bm4017034] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Audrey Roy
- University of
Le Havre, URCOM, EA 3221, FR CNRS 3038, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex, France
| | - Sébastien Comesse
- University of
Le Havre, URCOM, EA 3221, FR CNRS 3038, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex, France
| | - Michel Grisel
- University of
Le Havre, URCOM, EA 3221, FR CNRS 3038, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex, France
| | - Nicolas Hucher
- University of
Le Havre, URCOM, EA 3221, FR CNRS 3038, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex, France
| | - Zied Souguir
- Laboratoire
Polymeres Biopolymeres Surfaces, University of Rouen, F-76821 Mont St. Aignan, France
| | - Frédéric Renou
- University of
Le Havre, URCOM, EA 3221, FR CNRS 3038, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex, France
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Kool MM, Schols HA, Delahaije RJ, Sworn G, Wierenga PA, Gruppen H. The influence of the primary and secondary xanthan structure on the enzymatic hydrolysis of the xanthan backbone. Carbohydr Polym 2013; 97:368-75. [DOI: 10.1016/j.carbpol.2013.05.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/16/2013] [Accepted: 05/20/2013] [Indexed: 11/17/2022]
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14
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Establishment, in silico analysis, and experimental verification of a large-scale metabolic network of the xanthan producing Xanthomonas campestris pv. campestris strain B100. J Biotechnol 2013; 167:123-34. [DOI: 10.1016/j.jbiotec.2013.01.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/28/2013] [Accepted: 01/28/2013] [Indexed: 11/20/2022]
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15
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Fitzpatrick P, Meadows J, Ratcliffe I, Williams PA. Control of the properties of xanthan/glucomannan mixed gels by varying xanthan fine structure. Carbohydr Polym 2013; 92:1018-25. [DOI: 10.1016/j.carbpol.2012.10.049] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/18/2012] [Accepted: 10/19/2012] [Indexed: 11/30/2022]
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16
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Pinto EP, Furlan L, Vendruscolo CT. Chemical deacetylation natural xanthan (Jungbunzlauer®). POLIMEROS 2011. [DOI: 10.1590/s0104-14282011005000005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Borges CD, de Paula RC, Feitosa JP, Vendruscolo CT. The influence of thermal treatment and operational conditions on xanthan produced by X. arboricola pv pruni strain 106. Carbohydr Polym 2009. [DOI: 10.1016/j.carbpol.2008.07.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Pyruvated saccharides — Novel strategies for oligosaccharide synthesis. Top Curr Chem (Cham) 2008. [DOI: 10.1007/bfb0119224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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19
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Sereno NM, Hill SE, Mitchell JR. Impact of the extrusion process on xanthan gum behaviour. Carbohydr Res 2007; 342:1333-42. [DOI: 10.1016/j.carres.2007.03.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/12/2007] [Accepted: 03/22/2007] [Indexed: 11/16/2022]
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20
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Kim BS, Takemasa M, Nishinari K. Synergistic Interaction of Xyloglucan and Xanthan Investigated by Rheology, Differential Scanning Calorimetry, and NMR. Biomacromolecules 2006; 7:1223-30. [PMID: 16602742 DOI: 10.1021/bm050734+] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new synergistic interaction between tamarind seed xyloglucan and xanthan was found and investigated by rheology, differential scanning calorimetry (DSC), and NMR. The effect of the acetyl and pyruvate groups in the side chain in xanthan on the synergistic interaction was also examined. The shear moduli G' and G' ' of the mixture solution of xyloglucan and native (or acetate-free) xanthan increased steeply at around 22 degrees C upon cooling. An exothermic DSC peak appeared at the same temperature. A drastic decrease in the of the acetyl and pyruvate groups of the xanthan side chain was observed from 1H NMR spectra only in the mixture at low temperatures (<25 degrees C). It was found that the pyruvate group is more restricted in the mixture solution compared with the acetyl group. The mixture of xyloglucan and pyruvate-free xanthan showed no synergistic interaction. We concluded that this synergistic interaction is caused by the intermolecular binding between xyloglucan and xanthan, and, in the heterotypic junction zones, the xanthan side chain becomes a new state that is different from both the coil and helix states.
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Affiliation(s)
- Bo-Sook Kim
- Department of Food and Human Health Sciences, Osaka City University, 3-3-138 Sugimoto, Osaka 558-8585, Japan
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22
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Rodd A, Cooper-White J, Dunstan D, Boger D. Gel point studies for chemically modified biopolymer networks using small amplitude oscillatory rheometry. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00311-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Affiliation(s)
- I W Sutherland
- Institute of Cell and Molecular Biology, Edinburgh University, UK
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24
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Bresolin TM, Milas M, Rinaudo M, Reicher F, Ganter JL. Role of galactomannan composition on the binary gel formation with xanthan. Int J Biol Macromol 1999; 26:225-31. [PMID: 10569283 DOI: 10.1016/s0141-8130(99)00087-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The influence of the galactomannan characteristic ratios (M/G) on the temperature of gelation (Tg) and the gel strength of mixtures of galactomannan with xanthan is reported. Two galactomannans were investigated: one highly substituted from the seeds of Mimosa scabrella (M/G = 11), and the other, less substituted, from the endosperm of Schizolobium parahybae, with (M/G = 30) [Ganter JLMS, Zawadzki-Baggio SF, Leitner SC, Sierakowski MR, Reicher F. J Carbohydr Chem 1993;12:753]. The xanthan:galactomannan systems (4:2 g l(-1), in 5 mM NaCl) showed a temperature of gel formation (Tg) of 24 degrees C for that of S. parahybae [Bresolin TMB, Milas M, Rinaudo M and Ganter JLMS. Int J Biol Macromol 1998;23:263] and 20 degrees C for the galactomannan of M. scabrella, determined by viscoelastic measurements and microcalorimetry. A Tg of 40-50 degrees C was found by Shatwell et al. [Shatwell KP, Sutherland IW, Ross-Murphy SB, Dea ICM. Carbohydr Polym 1991;14:29] for locust bean gum-LBG (M/G = 43). Lundin and Hermansson [Lundin L, Hermansson AM. Carbohydr Polym 1995;26:129] reported a difference of 13 degrees C for Tg of two LBG samples with M/G = 3 (40 degrees C) and 5 (53 degrees C), in mixtures with xanthan. It appears that the more substituted galactomannans have lower temperatures of gelation in the presence of xanthan. The mechanism of gelation depends also on the M/G ratio. For the lower values it involves only disordered xanthan chains in contrast to M/G ratios higher than 3. In addition, the presence of the galactomannan from M. scabrella increased slightly the temperature of the conformational change (Tm) of xanthan probably due to the ionic strength contribution of proteins (3.9%) present in the galactomannan. On the other hand, the galactomannans from S. parahybae, with 1.5% of proteins and M. scabrella, with 2.4% of protein, did not show this effect, the Tm of xanthan alone or in a mixture being practically unchanged.
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Affiliation(s)
- T M Bresolin
- Centre de Recherches sur les Macromolécules Végétales-CNRS, affiliated with Université Joseph Fourier, Grenoble, France
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25
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Ruijssenaars HJ, de Bont JA, Hartmans S. A pyruvated mannose-specific xanthan lyase involved in xanthan degradation by Paenibacillus alginolyticus XL-1. Appl Environ Microbiol 1999; 65:2446-52. [PMID: 10347025 PMCID: PMC91360 DOI: 10.1128/aem.65.6.2446-2452.1999] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/1998] [Accepted: 03/24/1999] [Indexed: 11/20/2022] Open
Abstract
The xanthan-degrading bacterium Paenibacillus alginolyticus XL-1, isolated from soil, degrades approximately 28% of the xanthan molecule and appears to leave the backbone intact. Several xanthan-degrading enzymes were excreted during growth on xanthan, including xanthan lyase. Xanthan lyase production was induced by xanthan and inhibited by glucose and low-molecular-weight enzymatic degradation products from xanthan. A xanthan lyase with a molecular mass of 85 kDa and a pI of 7.9 was purified and characterized. The enzyme is specific for pyruvated mannosyl side chain residues and optimally active at pH 6.0 and 55 degrees C.
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Affiliation(s)
- H J Ruijssenaars
- Division of Industrial Microbiology, Department of Food Technology and Nutritional Sciences, Wageningen University, 6700 EV Wageningen, The Netherlands.
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Chiovitti A, Bacic A, Craik DJ, Munro SL, Kraft GT, Liao ML. Cell-wall polysaccharides from Australian red algae of the family Solieriaceae (Gigartinales, Rhodophyta): novel, highly pyruvated carrageenans from the genus Callophycus. Carbohydr Res 1997. [DOI: 10.1016/s0008-6215(97)00017-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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27
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Ross-Murphy S, Shatwell K, Sutherland I, Dea I. Influence of acyl substituents on the interaction of xanthans with plant polysaccharides. Food Hydrocoll 1996. [DOI: 10.1016/s0268-005x(96)80062-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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Gamini A, Mandel M. Physicochemical properties of aqueous xanthan solutions: static light scattering. Biopolymers 1994; 34:783-97. [PMID: 8025222 DOI: 10.1002/bip.360340610] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The secondary structure of xanthan in solutions of relatively low salt concentration and at room temperature has been investigated using static light scattering experiments. Additional evidence has been found for a dimeric structure at 25 degrees C in 0.01 M NaCl. From the experimental z-average mean square (ms) radius of gyration, a value for the persistence length p has been estimated, taking explicitly into account the polydispersity of the three samples used, which has been established by gel permeation chromatography (GPC) measurements. The experimental particle scattering functions of the three samples are consistent with theoretical estimates for polydisperse systems with the same value of p = 65 +/- 10 nm and the molar mass per unit length for a dimeric structure. This secondary structure remains unaffected by the ionic strength in the 0.005-0.01 M range. Partial aggregation seems to occur at higher NaCl concentrations. Light scattering and GPC data show that heating the xanthan 0.01 M NaCl solutions to about 70 degrees C considerably reduces the Mw of the low molar mass sample (2.3 x 10(5) g.mol-1), contrary to what is observed for the high molar mass sample (1.8 x 10(6) g.mol-1). These experimental findings can be accounted for by a partial temperature-induced dissociation of the xanthan dimers according to an all-or-none mechanism.
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Affiliation(s)
- A Gamini
- Department of Physical and Macromolecular Chemistry, Gorlaeus Laboratories, Leiden University, The Netherlands
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29
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Miertus S, Navarini L, Cesàro A. Configurational stability and molecular dynamics of acetal-linked pyruvate substituents in polysaccharides. Carbohydr Res 1994; 257:227-38. [PMID: 8013006 DOI: 10.1016/0008-6215(94)80037-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Pyruvate groups occur naturally in many microbial polysaccharides as nonsaccharidic components and significantly affect their physicochemical and biological properties. The configuration of the acetal carbon of pyruvate groups is mainly influenced by the favoured equatorial orientation of the methyl group. Evaluation of conformational energies has been carried out to assess the relative stabilities of the R and S isomers as a function of configuration and torsional angles for several residue models, including methyl 4,6-O-(1-carboxyethylidene)-alpha-D-galactopyranoside (1). Different levels of theoretical approach are used ranging from ab initio, semiempirical (AM1), and molecular mechanics (MM) methods up to molecular dynamics (MD). The higher stability of the isomer R of 1 was demonstrated by all of the methods used, thus giving full agreement with the NMR data on the natural compounds.
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Affiliation(s)
- S Miertus
- International Institute of Pure and Applied Chemistry, Trieste, Italy
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30
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Abstract
Sufficient well-characterized microbial exopolysaccharides are now available to permit extensive studies on the relationship between their chemical structure and their physical attributes. This is seen even in homopolysaccharides with relatively simple structures but is more marked when greater differences in structure exist, as are found in several heteropolysaccharides. The specific and sometimes unique properties have, in the case of several of these polymers, provided a range of commercial applications. The existence of "families" of structurally related polysaccharides also indicates the specific role played by certain structures and substituents; the characteristics of several of these microbial polysaccharide families will be discussed here. Thus, microbial exopolysaccharides frequently carry acyl groups which may profoundly affect their interactive properties although these groups often have relatively little effect on solution viscosity. Xanthan with or without acylation shows marked differences in synergistic gelling with plant gluco- and galacto-mannans, although the polysaccharides with different acylation patterns show similar viscosity. Similarly "gelrite" from the bacterium originally designated as Auromonas (Pseudomonas)elodea is of greater potential value after deacetylation, when it provides a valuable gelling agent, than it is as a viscosifier in the natural acylated form. The Klebsiella type 54 polysaccharide only forms gels when it, too, has been chemically deacetylated to give a structure equivalent to the Enterobacter XM6 polymer. Both these polysaccharides form gels due to the enhanced interaction with cations following deacylation and to the conformation adopted after removal of the acyl groups. Recent work in our laboratory suggests that deacetylation of certain bacterial alginates also significantly increases ion binding by these polysaccharides, making them more similar in their properties to algal alginates even although the alginates from some Pseudomonas species lack poly-L-guluronic acid sequences. The existence within families of polysaccharides of types in which monosaccharides are altered within a specific structure, or with varying side-chains, also gives an indication of the way in which such substituents affect the physical properties of the polymers in aqueous solution.
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Affiliation(s)
- I W Sutherland
- Institute of Cell and Molecular Biology, Division of Biology, University of Edinburgh, Scotland
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31
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Takigami S, Shimada M, Williams PA, Phillips GO. E.s.r. study of the conformational transition of spin-labelled xanthan gum in aqueous solution. Int J Biol Macromol 1993; 15:367-71. [PMID: 8110659 DOI: 10.1016/0141-8130(93)90055-q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The order to disorder transition of xanthan molecules in aqueous solutions has been studied using e.s.r. spectroscopy. Nitroxide spin-label was covalently attached to carboxyl groups on the xanthan side chains. The e.s.r. spectra obtained for aqueous spin-labelled xanthan solutions at varying ionic strengths contained both isotropic and anisotropic components at room temperature. The anisotropic component was attributed to the association of the side chains with the xanthan cellulosic backbone and was found to be present in greater proportions at increasing ionic strength. The spectra gradually changed with rising temperature and the proportion of anisotropic component decreased. This spectral change reflected the disruption of the side chain association with the backbone during the conformational change. Hysteresis effects were observed following sequential heating and cooling cycles suggesting that chain aggregation occurred.
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Affiliation(s)
- S Takigami
- Faculty of Engineering, Gunma University, Japan
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Stankowski JD, Mueller BE, Zeller SG. Location of a second O-acetyl group in xanthan gum by the reductive-cleavage method. Carbohydr Res 1993; 241:321-6. [PMID: 8472258 DOI: 10.1016/0008-6215(93)80123-v] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Navarini L, Cesàro A, Ross-Murphy SB. Viscoelastic properties of aqueous solutions of an exocellular polysaccharide from cyanobacteria. Carbohydr Polym 1992. [DOI: 10.1016/0144-8617(92)90091-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kitamura S, Takeo K, Kuge T, Stokke BT. Thermally induced conformational transition of double-stranded xanthan in aqueous salt solutions. Biopolymers 1991; 31:1243-55. [PMID: 1777578 DOI: 10.1002/bip.360311102] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The thermally induced conformational transition of double-stranded xanthans (degree of pyruvate substitution, DSp = 0.45) having Mw = 3.1, 5.7, and 20.3 x 10(5) has been studied in aqueous salt solutions by high-sensitivity differential scanning calorimetry (DSC). The double strandedness of these samples in the ordered conformation was ascertained by the value of mass per unit length, ML = 2090 +/- 270 g mol-1 nm-1, which was determined from the contour length obtained by electron microscopic observations and the molecular weight by light scattering measurements. The temperature at half completion of the transition T 1/2 for these samples increased linearly with the logarithm of the cation (Na+, K+) concentration. The plot of 1/T1/2 vs the natural logarithm of cation (Na+) concentration in mM for the sample with Mw = 5.7 x 10(5) (15-SX) yielded the equation 10(3)/T1/2 = 3.45-0.159 ln [Na+]. The specific enthalpy delta hcal for 15-SX, essentially independent of salt concentration above 20 mM, was 8.31 +/- 0.39 J/g (SD, n = 6). No systematic dependence of molecular weight on the transition temperature and the enthalpy was observed. Application of the Manning polyelectrolyte theory to the system using the DSC data suggested that the separation of the double strand of xanthan into two single chains was not completed at the temperature where the endothermic peak was finished. This suggestion is consistent with recent findings by light scattering measurements as a function of temperature. Our DSC study was extended to include four other samples from various sources. It was found that T1/2 and delta hcal depend on the pyruvate contents of the samples. For example, the t1/2 (t1/2/degrees C = T1/2/K - 237.15) values for samples with high pyruvate content (DSp = 0.9) and depyruvated (DSp = 0.14) in 20 mM aqueous NaCl were 48.8 and 85.3 degrees C, respectively. Two other samples showed relatively broad DSC curves having shoulders, which were resolved into two independent components. Thermodynamic parameters for each component were examined as a function of salt concentration, and the results obtained were interpreted in terms of the heterogeneity of the pyruvate content of the samples.
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Affiliation(s)
- S Kitamura
- Department of Agricultural Chemistry, Kyoto Prefectural University, Japan
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HWANG JAEKWAN, KOKINI JOZEFL. STRUCTURE AND RHEOLOGICAL FUNCTION OF SIDE BRANCHES OF CARBOHYDRATE POLYMERS. J Texture Stud 1991. [DOI: 10.1111/j.1745-4603.1991.tb00011.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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