Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

Sarılmışer, Hande Kazak; Ateş, Özlem; Ozdemir, Gonca; Arğa, Kazım Yalçın; Öner, Ebru Toksoy

doi:10.1016/j.jbiosc.2014.09.019

Cited by 82 publications

(31 citation statements)

References 51 publications

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“…Levans of Erwinia herbicola and Zymomonas mobilis have a moderate molecular weight (Table 1) and similar level of branching [70]. Most interestingly, the Halomonas smyrnensis levan which is of moderate molecular weight (Table 1), is characterized as unbranched [63]. According to our knowledge, this is the first example of an unbranched levan of bacterial origin.…”

Section: Resultsmentioning

confidence: 99%

A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass

et al. 2017

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Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a β-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3 of Pseudomonas syringae pv. tomato, its mutant Asp300Asn, levansucrases of Zymomonas mobilis, Erwinia herbicola, Halomonas smyrnensis as well as on levan isolated from timothy grass. For the first time a plant levan is shown as a perfect substrate for an endo-fructanase of a human gut bacterium. BT1760 degraded levans to FOS with degree of polymerization from 2 to 13. At optimal reaction conditions up to 1 g of FOS were produced per 1 mg of BT1760 protein. Low molecular weight (<60 kDa) levans, including timothy grass levan and levan synthesized from sucrose by the Lsc3Asp300Asn, were degraded most rapidly whilst levan produced by Lsc3 from raffinose least rapidly. BT1760 catalyzed finely at human body temperature (37°C) and in moderately acidic environment (pH 5–6) that is typical for the gut lumen. According to differential scanning fluorimetry, the Tm of the endo-levanase was 51.5°C. All tested levans were sufficiently stable in acidic conditions (pH 2.0) simulating the gastric environment. Therefore, levans of both bacterial and plant origin may serve as a prebiotic fiber for B. thetaiotaomicron and contribute to short-chain fatty acids synthesis by gut microbiota. In the genome of Bacteroides xylanisolvens of human origin a putative levan degradation locus was disclosed.

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Section: Resultsmentioning

confidence: 99%

A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass

et al. 2017

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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%

“…Levan concentration is influenced mainly by sucrose concentration, and also by other factors such as incubation time, temperature, initial pH, presence of yeast extract and Mg 2+ , NaCl, thiamine content, etc. (Ernandes and Garcia-Cruz, 2011; Santos et al, 2014; Silbir et al, 2014; Zhang et al, 2014; Santos-Moriano et al, 2015; Sarilmiser et al, 2015). …”

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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“…By increasing the oxidation degree, the anti-cancer activity also increased. Therefore, it was clearly demonstrated that the introduction of the chemically modified group, aldehydes, into the linear levan molecule could significantly enhance the antitumor activity of levan polysaccharide [121].…”

Section: Bacteriamentioning

confidence: 99%

Halophiles and Their Biomolecules: Recent Advances and Future Applications in Biomedicine

2019

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The organisms thriving under extreme conditions better than any other organism living on Earth, fascinate by their hostile growing parameters, physiological features, and their production of valuable bioactive metabolites. This is the case of microorganisms (bacteria, archaea, and fungi) that grow optimally at high salinities and are able to produce biomolecules of pharmaceutical interest for therapeutic applications. As along as the microbiota is being approached by massive sequencing, novel insights are revealing the environmental conditions on which the compounds are produced in the microbial community without more stress than sharing the same substratum with their peers, the salt. In this review are reported the molecules described and produced by halophilic microorganisms with a spectrum of action in vitro: antimicrobial and anticancer. The action mechanisms of these molecules, the urgent need to introduce alternative lead compounds and the current aspects on the exploitation and its limitations are discussed.

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Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

Cited by 82 publications

References 51 publications

A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass

A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass

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

Halophiles and Their Biomolecules: Recent Advances and Future Applications in Biomedicine

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