Determination of the viscoelastic properties of a homologous series of the fermentation polymer xanthan gum

Arendt, Oliver; Kulicke, Werner‐Michael

doi:10.1002/(sici)1522-9505(19981001)259:1<61::aid-apmc61>3.3.co;2-m

Cited by 4 publications

(9 citation statements)

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“…Functional domains of MiXen were predicted by the InterProScan web server. MiXen consisted of a cellulase N-terminal Ig-like domain (Ala 34 to Glu 124 ), a putative family 9 glycoside hydrolase (GH9) catalytic domain (Asp 125 to Ser 580 ), and a suspected carbohydrate-binding module (CBM) at the C terminus (Arg 700 to Glu 848 ).…”

Section: Resultsmentioning

confidence: 99%

“…It is known that the final degree of enzymolysis could be influenced by the secondary xanthan structure (8), and that changes in xanthan structure depend on different factors, including temperature, pH, ionic strength, and modifications of the xanthan side chain (20,34,35). In this study, xanthan degradation was conducted under set temperature, pH, and ionic strength; thus, the effect of xanthan side chain modification on MiXen activity via changes in xanthan structure was further investigated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Yang

Sun

et al. 2019

Appl Environ Microbiol

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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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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Yang

Sun

et al. 2019

Appl Environ Microbiol

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“…Nevertheless, a more realistic representation leads to limit the mathematical development to four terms, which correspond to interactions between a maximum of four neighboring macromolecules 6 Specific viscosity of polysaccharide aqueous solutions as a function of overlap parameter: (□) xanthan gum in 0.1 M NaCl ( k H ≈ 0.6), data of Arendt et al; (·) guar gum in water ( k H ≈ 0.4), data of Launay et al; (▴) pullulan in water, data of Lazaridou et al; (○) chitosan in 0.3 M AcOH/0.05 M AcONa, data of Desbrieres …”

Section: Discussionmentioning

confidence: 99%

“…The temperature sensitivity of cellulose ethers is well-known. In particular, the thermothickening behavior observed with some of them has been largely described. − Other inverse temperature behaviors have been briefly reported with derivatives of chitosan or inulin and even for xanthan gum . Nevertheless, to the best of our knowledge, there is no detailed examination of the relation between the chemical structure of the polymers and the temperature sensitivity of their aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Aqueous Solutions of Native and Hydrophobically Modified Polysaccharides: Temperature Effect

Durand

Dellacherie

2006

Biomacromolecules

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Amphiphilic polysaccharides, obtained by the attachment of various hydrocarbon groups onto dextran, are studied in aqueous solutions. The viscosity of their aqueous solutions is examined as a function of concentration and temperature in the range 25-65 degrees C. Varying polymer concentration, viscosity follows a polynomial development of Huggins equation in which the coefficients can be calculated from the Huggins constant determined in the dilute domain (Matsuoka-Cowman equation). For all polymers, the solution viscosity follows an Arrhenius-like variation with temperature. The activation energy of the aqueous solutions is determined as a function of polymer concentration and structural characteristics (nature and amount of grafted hydrocarbon groups). The variation of activation energy with polymer concentration is shown to be consistent with predictions based on the Matsuoka-Cowman equation combined with the equation of Andrade. This conclusion is extended to other polysaccharides using data from the literature.

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“…Xanthan gum (XG) is a natural microbial hetero-polysaccharide produced by fermentation of the micro-organism Xanthomonas campestris [ 15 ]. It consists of a cellulosic backbone (1-4 β-linked d -glucose units) with a side-chain consisting of two d -mannose units and one d -glucuronic acid at the C3 atom of alternating glucose units ( Figure 1 b) [ 16 ]. Internal d -mannose, which is connected to the backbone, has an acetyl group at O6, while approximately 50% of the terminal d -mannose forms a pyruvic acid group between position C4 and C6 [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Protonation State and N-Acetylation of Chitosan on Its Interaction with Xanthan Gum: A Molecular Dynamics Simulation Study

et al. 2017

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Hydrophilic matrices composed of chitosan (CS) and xanthan gum (XG) complexes are of pharmaceutical interest in relation to drug delivery due to their ability to control the release of active ingredients. Molecular dynamics simulations (MDs) have been performed in order to obtain information pertaining to the effect of the state of protonation and degree of N-acetylation (DA) on the molecular conformation of chitosan and its ability to interact with xanthan gum in aqueous solutions. The conformational flexibility of CS was found to be highly dependent on its state of protonation. Upon complexation with XG, a substantial restriction in free rotation around the glycosidic bond was noticed in protonated CS dimers regardless of their DA, whereas deprotonated molecules preserved their free mobility. Calculated values for the free energy of binding between CS and XG revealed the dominant contribution of electrostatic forces on the formation of complexes and that the most stable complexes were formed when CS was at least half-protonated and the DA was ≤50%. The results obtained provide an insight into the main factors governing the interaction between CS and XG, such that they can be manipulated accordingly to produce complexes with the desired controlled-release effect.

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Determination of the viscoelastic properties of a homologous series of the fermentation polymer xanthan gum

Cited by 4 publications

References 0 publications

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Aqueous Solutions of Native and Hydrophobically Modified Polysaccharides: Temperature Effect

Effect of Protonation State and N-Acetylation of Chitosan on Its Interaction with Xanthan Gum: A Molecular Dynamics Simulation Study

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