An influence of ethanol and temperature on products formation by different preparations of Zymomonas mobilis extracellular levansucrase

Vigants, Armands; Upite, D.; Scherbaka, Rita; Lukjanenko, Jekaterina; Ionina, Rita

doi:10.1007/s12223-012-0185-7

Cited by 13 publications

(11 citation statements)

References 19 publications

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“…The hydrolysis of the already-synthesized levan could result from a combination of factors such as enzymatic activities (Tanaka et al, 1978; Vigants et al, 2013) and acid hydrolysis or pH instability (Runyon et al, 2014; Sarilmiser et al, 2015). As reported for levansucrases from other bacterial species such as Z. mobilis (Yanase et al, 1992) and B. subtilis (Tanaka et al, 1978), levansucrases exhibit not only the fructosyltransferase activity, which transfers a fructose molecule from sucrose to the growing chain of levan (levan synthesis), but also an intrinsic levanase activity that releases a fructosyl moiety of a levan chain if water is used as acceptor (levan hydrolysis).…”

Section: Discussionmentioning

confidence: 99%

Fermentation pH Modulates the Size Distributions and Functional Properties of Gluconobacter albidus TMW 2.1191 Levan

2017

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Bacterial levan has gained an increasing interest over the last decades due to its unique characteristics and multiple possible applications. Levan and other exopolysaccharides (EPSs) production are usually optimized to obtain the highest concentration or yield while a possible change of the molecular size and mass during the production process is mostly neglected. In this study, the molar mass and radius of levan samples were monitored during fermentations with the food-grade, levan-producing acetic acid bacterium Gluconobacter (G.) albidus TMW 2.1191 in shake flasks (without pH control) and bioreactors (with pH control at 4.5, 5.5 and 6.5, respectively). In uncontrolled fermentations, the levan size/molar mass continuously decreased concomitantly with the continuous acidification of the nutrient medium. On the contrary, the amount, molar mass and size of levan could be directly influenced by controlling the pH during fermentation. Using equal initial substrate amounts, the largest weight average molar mass and geometric radius of levan were observed at constant pH 6.5, while the highest levan concentration was obtained at constant pH 4.5. Since there is a special demand to find suitable hydrocolloids from food-grade bacteria to develop novel gluten-free (GF) products, these differently produced levans were used for baking of GF breads, and the best quality improvement was obtained by addition of levan with the highest mass and radius. This work, therefore, demonstrates for the first time that one bacterial strain can produce specific high molecular weight fractions of one EPS type, which differ in properties and sizes among each other in dependence of the controllable production conditions.

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Section: Discussionmentioning

confidence: 99%

Fermentation pH Modulates the Size Distributions and Functional Properties of Gluconobacter albidus TMW 2.1191 Levan

2017

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“…1. Therefore the spectrum of oligomeric reaction products of Lsc3 is similar to that of levansucrases from G. diazotrophicus, Z. mobilis and B. megaterium [50,52,53,93]. A low yield of 6-kestose and absence of neokestose formation differentiate Lsc3 [96] from yeast and fungal b-fructofuranosidases [54][55][56][57][59][60][61].…”

Section: Synthesis Of Fos and Levan By Levansucrases Of Pseudomonas Bmentioning

confidence: 99%

“…Schwanniomyces occidentalis and Rhodotorula dairenensis) also produce a considerable amount of 6-kestose from sucrose [54][55][56]. For some levansucrases, such as the LevU of Z. mobilis [53], synthesis of neokestose has also been recorded. In neokestose (belongs to neo-FOS; DP 3; Fig.…”

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confidence: 99%

“…As this enzyme produces levan, it should also synthesize 6-kestose (DP 3; Figs 1 and 2) that does not accumulate as it is efficiently extended [50]. The Z. mobilis levansucrase also produces 1-kestose as the major oligosaccharidic product [52], but 6-kestose is also detected among the reaction products [53]. Interestingly, b-fructofuranosidases of several filamentous fungi (e.g.…”

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confidence: 99%

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Levansucrases of a Pseudomonas syringae pathovar as catalysts for the synthesis of potentially prebiotic oligo- and polysaccharides

2015

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“…Structural studies recently pointed out that the main differences between FOS and levan-producing enzymes are located on the surface loops [12,20]. Levansucrase from Z. mobilis; on the other hand, can produce both levan and FOS depending on the reaction conditions [9,21,22,23]. There are several studies investigating the Z. mobilis levansucrase product specificity based on amino acid mutagenesis approaches.…”

Section: Introductionmentioning

confidence: 99%

Structural Modelling and Structure-Function Analysis of <i>Zymomonas mobilis</i> Levansucrase

Bakar¹,

Türköz²

2017

SDÜ Fen Bil Enst Der

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Levansucrases are bacterial enzymes which produce fructan polymers from sucrose via hydrolysis and transfructosylation activities. These polymers; levan and fructooligosaccharides are valuable for food and pharmaceutical industries. Levansucrases from Gram-positive bacteria such as Bacillus subtilis tend to produce levan, while those from Gram-negative bacteria preferentially produce fructooligosaccharides. Zymomonas mobilis is an efficient levansucrase producer and its extracellular levansucrase can produce both fructooligosaccharides and levan depending on the reaction parameters. In this study, the structure of Z. mobilis levansucrase was modeled in order to help to understand the structure-function relationship of the enzyme. Furthermore, amino acids previously reported to be important for levansucrase activity were mapped on the model. The structural model presents a five-bladed propeller with a deep, negatively charged central pocket, similar to other bacterial levansucrases. Mapping showed that amino acids which previously reported to affect fructan length are located on the periphery of the structure covering the active site central pocket. Thus it is showed that, for the first time, that hydrolysis and transfructosylation reactions are catalyzed on different parts of Z. mobilis levansucrase structure. The structural location of the critical amino acids will pave the way to identify other residues which control fructan length by site directed mutagenesis without altering the overall fold of the enzyme.

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An influence of ethanol and temperature on products formation by different preparations of Zymomonas mobilis extracellular levansucrase

Cited by 13 publications

References 19 publications

Fermentation pH Modulates the Size Distributions and Functional Properties of Gluconobacter albidus TMW 2.1191 Levan

Fermentation pH Modulates the Size Distributions and Functional Properties of Gluconobacter albidus TMW 2.1191 Levan

Levansucrases of a Pseudomonas syringae pathovar as catalysts for the synthesis of potentially prebiotic oligo- and polysaccharides

Structural Modelling and Structure-Function Analysis of <i>Zymomonas mobilis</i> Levansucrase

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