Nutritional requirements of Zymomonas mobilis CCT 4494 for levan production

Ernandes, Fernanda Maria Pagane Guereschi; García-Cruz, Crispin Humberto

doi:10.1590/s1516-89132011000300021

Cited by 11 publications

(4 citation statements)

References 27 publications

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“…However, generalizations should be avoided for the fermentation conditions due to the diversity of the nutritional and environmental requirements of the EPS producer strains (23). Optimum conditions for EPS synthesis are affected by limitations of nitrogen and phosphate sources, oxygen content, pH, temperature, proportion between the air and medium volume, agitation rate, inoculum size and also nutrients in the culture medium (24). Therefore, in this study, effective stimulating factors for microbial levan production by H. smyrnensis AAD6 T were investigated.…”

Section: Resultsmentioning

confidence: 99%

Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

Sarılmışer

Ateş

Ozdemir

et al. 2015

Journal of Bioscience and Bioengineering

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Section: Resultsmentioning

confidence: 99%

Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

Sarılmışer

Ateş

Ozdemir

et al. 2015

Journal of Bioscience and Bioengineering

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“…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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“…Studies by Ernandes and García‐Cruz () with free cells showed that increasing the sucrose concentration proportionately affects cell growth and levan formation. However, this was not observed in the present study.…”

Section: Resultsmentioning

confidence: 99%

Alginate/PVA Beads for Levan Production by Zymomonas mobilis

Lorenzetti

Moro

García-Cruz

2014

J Food Process Engineering

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The levan is a biopolymer of great importance to the food industry since it is capable of defining and modifying the structure of one food, acting as stabilizer, thickener, gelling agent and being largely responsible for the texture of processed foods. The levan production by bacterial cell immobilization may potentialize the results of these studies, having advantages such as: high cell concentrations inside the reactor, increase the substrate absorption rate, improve the performance and reduce the risk of microbial contamination. Thus, this study aims to evaluate the levan production by immobilized Zymomonas mobilis in hybrid system of alginate/polyvinyl alcohol (PVA) when submitted to different sucrose concentrations (5, 10, 25 and 30%), pH (5.7 and 7.0) and incubation temperature of 30C for 12, 18 and 24 h. The results showed that the best levan production rate was 18.66 g/L at 30% sucrose concentration, with productivity 1.55 g/L/h at pH 7.0. Practical Applications The biopolymer called levan is a nontoxic, nonmutagenic, odorless, tasteless and soluble dietary fiber; it has physiological effects that depend on its size and linkage type, and its fermentability. It can be produced by bacterial fermentation like Zymomonas mobilis. The administration of levan in human diet (5.5–6 g, twice a day) for 2–3 months reduced body weight and body fat mass. The input of levan showed in some studies an increase of divalent cation (Zn, Mg and Fe) and calcium absorption in rats. In the food industry, levan improves the rheological properties and functional characteristics of dairy products, such as yogurt. Its application includes use as a stabilizer, emulsifier, surface agent, encapsulating agent and flavor and fragrances carrier.

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Nutritional requirements of Zymomonas mobilis CCT 4494 for levan production

Abstract: ABSTRACT

Cited by 11 publications

References 27 publications

Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

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

Alginate/PVA Beads for Levan Production by Zymomonas mobilis

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