Kinetic modeling of oligosaccharide synthesis catalyzed by Leuconostoc mesenteroides NRRL B-1299 dextransucrase

Dols, M. J. L.; Remaud‐Siméon, Magali; Willemot, René‐Marc; Demuth, Bernd; Jördening, Hans‐Joachim; Buchholz, Klaus; Monsan, Pierre

doi:10.1002/(sici)1097-0290(19990505)63:3<308::aid-bit7>3.3.co;2-u

Cited by 6 publications

(10 citation statements)

References 21 publications

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“…As a consequence, though both soluble and insoluble dextransucrases were shown to produce ␣-1,2 GOS, the insoluble form of the enzyme (easily recovered and isolated) is used alone for the industrial process. The reaction kinetics have also been modeled recently (Dols et al, 1999) confirming the reaction scheme presented in Figure 1.…”

Section: Introductionsupporting

confidence: 56%

Factors affecting α,‐1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase

Dols‐Lafargue

Willemot

Monsan

et al. 2001

Biotech & Bioengineering

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The optimization of alpha-1,2 glucooligosaccharide (GOS) synthesis from maltose and sucrose by Leuconostoc mesenteroides NRRL B-1299 dextransucrase was achieved using experimental design and consecutive analysis of the key parameters. An increase of the pH of the reaction from 5.4 to 6.7 and of the temperature from 25 to 40 degrees C significantly favored alpha-1,2 GOS synthesis, thanks to a significant decrease of the side reactions, i.e., dextran and leucrose synthesis. These positive effects were not sufficient to compensate for the decrease of enzyme stability caused by the use of high pH and temperature. However, the critical parameters were the sucrose to maltose concentration ratio (S/M) and the total sugar concentration (TSC). Alpha1,2 GOS synthesis was favored at high S/M ratios. But using these conditions also led to an increase of side reactions which could be modulated by choosing the appropriate TSC. Finally, with S/M = 4 and TSC = 45% w/v, dextran and leucrose productions were limited and the final alpha-1,2 GOS yield reached 56.7%, the total GOS yield being 88%.

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Section: Introductionsupporting

confidence: 56%

Factors affecting α,‐1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase

Dols‐Lafargue

Willemot

Monsan

et al. 2001

Biotech & Bioengineering

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“…The cell growth on sucrose was reported to be virtually the same as the cell growth on the stoichiometrically equivalent mixture of glucose and fructose (25). The kinetics of cell growth and enzyme and exopolymer production have been well studied in our laboratory and can be found elsewhere (19,25).…”

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confidence: 94%

Effects of pH and Trace Minerals on Long-Term Starvation ofLeuconostoc mesenteroides

Kim

Thomas

Fogler

2000

Appl Environ Microbiol

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Laboratory experiments have definitively shown that exopolymer-producing bacteria have the potential to modify the flow of fluids in oil reservoirs to enhance oil production. Once injected into the reservoir, they will be subjected to a wide range of pH values and to starvation resulting from nutrient depletion. For successful field implementation it is necessary to have a fundamental understanding of these effects on the viability of bacteria. This paper addresses the effects of pH and trace minerals on cell viability of Leuconostoc mesenteroides during carbon source depletion. Two different carbon sources were used to grow cells before transferring the cells to starvation conditions: sucrose and a combination of glucose and fructose. These substrates were chosen because L. mesenteroides produces a significant amount of water-insoluble exopolymers (dextran) under sucrose-fed conditions, which may enhance cell survival under harsh conditions. The effects of dextran on the cell viability were tested at different pH values with and without trace minerals. The rate of cell death followed an exponential-decay law for different values of the solution pH. The optimal solution pH for survival was pH 5, whereas cells died rapidly at pH 3 and below and at pH 13 and above. The sucrose-fed cells showed a greater viability than cells fed glucose and fructose for all pH ranges tested. The results indicated that water-insoluble exopolymers help cells survive for longer periods of time under starvation conditions. The effects of trace minerals on cell culturability were tested at two pH values, 4.5 and 7. For both cases, cells showed a greater culturability (smaller decay rate constant) in the presence of trace minerals than without trace minerals. It was also found that the effects of trace minerals on cell culturability were greater for glucose-fructose-fed cells than for sucrose-fed cells. The Michaelis pH function theory was used for comparing the relationships between the cell decay rate and pH.

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“…We adopted a previously developed GTF model for the acceptor reaction (Heincke et al 1999). The significance of model parameters could be demonstrated by sensitivity analysis and the model has also been verified for other GTFs (Dols et al 1999). Equation (3) describes the substrate consumption neglecting substrate inhibition, which was not observed for this enzyme variant.…”

Section: Modelingmentioning

confidence: 99%

“…Particularly at high molar saccharide concentrations the sucrose concentration profiles were difficult to predict, which might suggest external transport limitations. Although GTFs exhibit multiple molecular interactions (Dols et al 1999;Heincke et al 1999;Ergezinger 2006), the kinetic model produces reasonable data with a low number of parameters. Next, modeling should integrate the in situ adsorption step.…”

Section: Characterization Of Gtf-r S628dmentioning

confidence: 99%

Development of a multiphase reaction system for integrated synthesis of isomaltose with a new glucosyltransferase variant

Erhardt¹,

Rosenstock²,

Hellmuth³

et al. 2009

Biocatalysis and Biotransformation

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A new genetically derived variant of the glucosyltransferase from Streptococcus oralis has been characterized physicochemically and kinetically. Compared with the industrially used glucosyltransferase from Leuconostoc mesenteroides, the enzyme variant GTF-R S628D possesses 25 times higher affinity for the specific glucosylation of glucose. For a concept of integrated reaction and product isolation, a fluidized bed reactor with in situ product removal was applied. The technical feasibility and the applicability of the kinetic models for reaction and adsorption could be demonstrated. The immobilized enzyme was stable (20% activity loss after 192 h) and product could be obtained with 90% purity. A bioprocess model was generated which allowed the integral assessment of the enzymatic synthesis and in situ product adsorption. The model is a powerful tool which assists with the localization of optimal process parameters. It was applied for the process evaluation of other glucosyltransferases and demonstrated key characteristics of each enzymatic system.

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Kinetic modeling of oligosaccharide synthesis catalyzed by Leuconostoc mesenteroides NRRL B-1299 dextransucrase

Cited by 6 publications

References 21 publications

Factors affecting α,‐1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase

Factors affecting α,‐1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase

Effects of pH and Trace Minerals on Long-Term Starvation ofLeuconostoc mesenteroides

Development of a multiphase reaction system for integrated synthesis of isomaltose with a new glucosyltransferase variant

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