Acetic acid bacteria encode two levansucrase types of different ecological relationship

Jakob, Frank; Quintero, Yamira; Musacchio, Andrea; Santos, Paulina Estrada‐de los; Hernández, Lázaro; Vogel, Rudi F.

doi:10.1111/1462-2920.14768

Cited by 19 publications

(17 citation statements)

References 101 publications

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“…However, it is yet unknown to what extent the size of levan influences its rheological properties. It was previously shown that levans produced by G. albidus TMW 2.1191 without external pH control are comparatively smaller in size at prolonged fermentation times, which might be due to (a combination of) continuous acidic hydrolysis, the intrinsic β-fructosidase activities of levansucrases or possibly additionally expressed β-fructosidases [10,20,35,36]. Accordingly, in the present study, the levan recovered from NaG medium after 48 h of incubation exhibited the lowest hydrodynamic volume/radius, at which an elevated nitrogen content was determined for this levan in comparison to the levans produced in Na-acetate buffers (pH 4.0 and 5.0).…”

Section: Discussionmentioning

confidence: 99%

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Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191

Hundschell

Braun

Wefers

et al. 2020

Foods

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Levan is a fructan-type exopolysaccharide which is produced by many microbes from sucrose via extracellular levansucrases. The hydrocolloid properties of levan depend on its molecular weight, while it is unknown why and to what extent levan is functionally diverse depending on its size. The aim of our study was to gain deeper insight into the size-dependent functional variability of levan. For this purpose, levans of different sizes were produced using the water kefir isolate Gluconobacter albidus TMW 2.1191 and subsequently rheologically characterized. Three levan types could be identified, which are similarly branched, but differ significantly in their molecular size and rheological properties. The smallest levan (<107 Da), produced without adjustment of the pH, exhibited Newton-like flow behavior up to a specific concentration of 25% (w/v). By contrast, larger levans (>108 Da) produced at pH ≥ 4.5 were shear-thinning, and the levan produced at pH 5.0 showed a gel-like behavior at 5% (w/v). A third (intermediate) levan variant was obtained through production in buffers at pH 4.0 and exhibited the properties of a viscoelastic fluid up to concentrations of 15% (w/v). Our study reveals that the rheological properties of levan are determined by its size and polydispersity, rather than by the amount of levan used or the structural composition.

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Section: Discussionmentioning

confidence: 99%

“…or Gluconobacter spp. produce levans [4][5][6][7][8][9][10]. Hence, levan is a natural component of sucrose-containing fermented foods such as sourdough breads [11], kefir [12] or natto [13,14].…”

Section: Introductionmentioning

confidence: 99%

Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191

Hundschell

Braun

Wefers

et al. 2020

Foods

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“…However, it is yet unknown to which extent the size of levan in fact influences its rheological properties. It was previously shown that levans produced by G. albidus TMW 2.1191 without external pH control are comparatively smaller in size at prolonged fermentation times, which might be due to (a combination of) continuous acidic hydrolysis, the intrinsic β-fructosidase activities of levansucrases or possibly additionally expressed β-fructosidases [9,19,32,33]. Accordingly, the levan recovered from NaG medium after 48 h of incubation in the present study exhibited the lowest hydrodynamic volume/radius.…”

Section: Discussionmentioning

confidence: 47%

“…or Gluconobacter spp. produce levans [3][4][5][6][7][8][9]. Hence, levan is a natural component of sucrose containing fermented foods like sourdough breads [10], kefir [11] or natto [12,13].…”

Section: Introductionmentioning

confidence: 99%

Size-Dependent Rheological Variability of Levan Produced by Gluconobacter Albidus TMW 2.1191

Hundschell¹,

Braun²,

Wefers³

et al. 2020

Preprint

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Levan is a fructan-type exopolysaccharide, which is produced by many microbes from sucrose via extracellular levansucrases. The hydrocolloid properties of levan depend on its molecular weight, while it is unknown why and to which extent levan is functionally diverse in dependence of its size. The aim of our study was to get deeper insights into the size-dependent, functional variability of levan. For this purpose, levans of different sizes were produced using the water kefir isolate Gluconobacter albidus TMW 2.1191 and subsequently rheologically characterized. Three levan types could be identified, which are similarly branched, but significantly differ in their molecular size and rheological properties among each other. The smallest levan (< 107 Da) produced without adjustment of the pH exhibited Newton-like flow behavior up to a specific concentration of 25% (w/v). On the contrary, larger levans (> 108 Da) produced at pH ≥ 4.5 were shear-thinning and showed a gel like behavior at ≥ 5% (w/v). A third (intermediate) levan variant was obtained via production in buffers at pH 4.0 and exhibited the properties of a viscoelastic fluid at ≥ 5% (w/v). Our study reveals that the variable size and composition of levan are controllable and more decisive for its functionality than the amount of exerted levan.

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“…6 ? Supplementary File 2), an additional expressed b-fructosidase (WP077802344) (Brandt et al 2017;Jakob et al 2019) and/or the possible intrinsic levanase activity (Méndez-Lorenzo et al 2015) of the levansucrase at certain conditions. The presented experimental approach could hence be used to control and trigger the sizes of globular levan molecules.…”

Section: Discussionmentioning

confidence: 99%

Insights into the pH-dependent, extracellular sucrose utilization and concomitant levan formation by Gluconobacter albidus TMW 2.1191

Jakob

Gebrande

Bichler

et al. 2020

Antonie van Leeuwenhoek

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Many bacteria and archaea produce the polydisperse fructose polymer levan from sucrose upon biofilm formation via extracellular levansucrases (EC 2.4.1.10). We have investigated levansucraserelease and -activities as well as molecular size of the levan formed by the acetic acid bacterium Gluconobacter albidus TMW 2.1191 at varying environmental pH conditions to obtain insight in the ecological role of its constitutively expressed levansucrase and the produced levan. A buffer system was established enabling the recovery of levansucrasecontaining supernatants from preincubated cell suspensions at pH 4.3-pH 5.7. The enzyme solutions were used to produce levans at different pH values and sucrose concentrations. Finally, the amounts and size distributions of the produced levans as well as the corresponding levansucrase activities were determined and correlated with each other. The data revealed that the levansucrase was released into the environment independently of its substrate sucrose, and that more levansucrase was released at pH C 5.0.The glucose release and formation of high molecular weight levans ([ 3.5 kDa) from 0.1 M initial sucrose was comparable between pH * 4.3-5.7 using equal amounts of released levansucrase. Hence, this type of levansucrase appears to be structurally adapted to changes in the extracellular pH and to exhibit a similar total activity over a wide acidic pH range, while it produced higher amounts of larger levan molecules at higher production pH and sucrose concentrations. These findings indicate the physiological adaptation of G. albidus TMW 2.1191 to efficient colonisation of sucrose-rich habitats via released levansucrases despite changing extracellular pH conditions in course of acid formation.

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Acetic acid bacteria encode two levansucrase types of different ecological relationship

Cited by 19 publications

References 101 publications

Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191

Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191

Size-Dependent Rheological Variability of Levan Produced by Gluconobacter Albidus TMW 2.1191

Insights into the pH-dependent, extracellular sucrose utilization and concomitant levan formation by Gluconobacter albidus TMW 2.1191

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