Utilization of electron acceptors by lactobacilli isolated from sourdough

Stolz, Peter; Bcker, Georg; Hammes, Walter P.; Vogel, Rudi F.

doi:10.1007/bf01193208

Cited by 107 publications

(47 citation statements)

References 19 publications

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“…Sourdough isolates of rodent-adapted lineage III were not suitable for use in competition experiments because they produce reutericyclin, an antimicrobial compound that inhibits other strains of L. reuteri (21). Strains were inoculated in modified MRS (mMRS) broth (8) and incubated at 37°C overnight. Two culture cocktails were prepared as biological repeats by mixing equal volumes of one strain from each origin to obtain approximately equal cell counts at the time of inoculation.…”

Section: Methodsmentioning

confidence: 99%

“…Type I doughs propagated in temperate climates are generally dominated by Lactobacillus sanfranciscensis (3,4), but type I doughs propagated in tropical climates harbor thermophilic lactobacilli, including Lactobacillus reuteri (5,6). The frequent occurrence of L. sanfranciscensis has been attributed to the rapid growth of this organism, the efficient use of maltose as a carbon source, the use of fructose as an electron acceptor, and its small genome size (7)(8)(9)(10). In contrast, type II doughs are used as baking improvers to modify flavor, texture, or shelf life in industrial processes in the form of active dough or dough that has been stabilized by drying or pasteurization (1).…”

mentioning

confidence: 99%

“…Previous studies suggested that specific metabolic traits of lactic acid bacteria influence their growth rate in cereal substrates and determine their competitiveness in artisanal and industrial sourdough fermentations (8,10,12). However, experimental validation of the effects of specific metabolic traits of lactobacilli on their competitiveness in sourdough is generally lacking.…”

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confidence: 99%

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Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

Lin

Gänzle

2014

Appl Environ Microbiol

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This study determined the effects of specific metabolic traits of Lactobacillus reuteri on its competitiveness in sourdoughs. The competitiveness of lactobacilli in sourdough generally depends on their growth rate; acid resistance additionally contributes to competitiveness in sourdoughs with long fermentation times. Glycerol metabolism via glycerol dehydratase (gupCDE) accelerates growth by the regeneration of reduced cofactors; glutamate metabolism via glutamate decarboxylase (gadB) increases acid resistance by generating a proton motive force. Glycerol and glutamate metabolisms are lineage-specific traits in L. reuteri; therefore, this study employed glycerol dehydratase-positive sourdough isolates of human-adapted L. reuteri lineage I, glutamate decarboxylase-positive strains of rodent-adapted L. reuteri lineage II, as well as mutants with deletions in gadB or gupCDE. The competitivenesses of the strains were quantified by inoculation of wheat and sorghum sourdoughs with defined strains, followed by propagation of doughs with a 10% inoculum and 12-h or 72-h fermentation cycles. Lineage I L. reuteri strains dominated sourdoughs propagated with 12-h fermentation cycles; lineage II L. reuteri strains dominated sourdoughs propagated with 72-h fermentation cycles. L. reuteri 100-23⌬gadB was outcompeted by its wild-type strain in sourdoughs fermented with 72-h fermentation cycles; L. reuteri FUA3400⌬gupCDE was outcompeted by its wild-type strain in sourdoughs fermented with both 12-h and 72-h fermentation cycles. Competition experiments with isogenic pairs of strains resulted in a constant rate of strain displacement of the less competitive mutant strain. In conclusion, lineage-specific traits of L. reuteri determine the competitiveness of this species in sourdough fermentations.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

Lin

Gänzle

2014

Appl Environ Microbiol

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“…Heterofermentative lactic acid bacteria ferment hexoses by the hexose-monophosphate pathway to equimolar amounts of lactate, ethanol and CO 2 . In addition, O. oeni and some other lactic acid bacteria produce substantial amounts of erythritol and acetate and some glycerol (Veiga- Da-Cunha et al 1992, 1993Stolz et al 1995). Erythritol is formed via fructose-6-P, which is cleaved by phosphoketolase to erythrose-4-P and acetyl-P. Erythrose-4-P is reduced to erythritol, and from acetyl-P acetate or ethanol are produced.…”

Section: Introductionmentioning

confidence: 98%

Significance of pantothenate for glucose fermentation by Oenococcus oeni and for suppression of the erythritol and acetate production

Richter

Vlad

Unden

2001

Archives of Microbiology

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The heterofermentative lactic acid bacterium Oenococcus oeni requires pantothenic acid for growth. In the presence of sufficient pantothenic acid, glucose was converted by heterolactic fermentation stoichiometrically to lactate, ethanol and CO2. Under pantothenic acid limitation, substantial amounts of erythritol, acetate and glycerol were produced by growing and resting bacteria. Production of erythritol and glycerol was required to compensate for the decreasing ethanol production and to enable the synthesis of acetate. In ribose fermentation, there were no shifts in the fermentation pattern in response to pantothenate supply. In the presence of pantothenate, growing O. oeni contained at least 10.2 microM HSCoA, whereas the HSCoA content was tenfold lower after growth in pantothenate-depleted media. HSCoA and acetyl-CoA are cosubstrates of phosphotransacetylase and acetaldehyde dehydrogenase from the ethanol pathway. Both enzymes were found with activities commensurate with their function in ethanol production during heterolactic fermentation. From the kinetic data of the enzymes and the HSCoA and acetyl-CoA contents, it can be calculated that, under pantothenate limitation, phosphotransacetylase, and in particular acetaldehyde dehydrogenase activities become limiting due to low levels of the cosubstrates. Thus HSCoA deficiency represents the major limiting factor in heterolactic fermentation of glucose under pantothenate deficiency and the reason for the shift to erythritol, acetate, and glycerol fermentation.

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“…This savoury taste is produced by adding sourdough to the dough, which contains yeast and lactic acid bacteria (Birch et al, 2013;Gobbetti, 1998). Sourdough is used to reduce the pH (Kunz, 1994;Stolz et al, 1995) as well as improving the sensory properties (Kunz, 1994;Thiele et al, 2002). The sourdough is produced by fermentation, whereby lactic acid bacteria produce acetate (Birch et al, 2013) and lactic acid as a function of ambient conditions (Ternes, 2008).…”

Section: Introductionmentioning

confidence: 99%

Influence of calcium acetate on rye bread volume

et al. 2016

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The positive accepted savoury taste of rye bread is dependent on acetate concentration in the dough of such breads. In order to study how calcium acetate influences rye bread properties, the pH of rye doughs fortified with calcium acetate and the resulting volume of the breads were measured. Furthermore, CD 2 formation of yeast with added calcium acetate and yeast with different pH levels (4, 7, 9) were measured. Thereby, it was determined that the addition of calcium acetate increased the pH of dough from 4.42 to 5.29 and significantly reduced the volume of the breads from 1235.19 mL to 885.52 mL. It could be proven that bread volume was affected by a 30.9% lower CD 2 amount production of yeast, although bread volume was not affected by changing pH levels. Due to reduced bread volume, high concentrations of calcium acetate additions are not recommended for improving rye bread taste.

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Utilization of electron acceptors by lactobacilli isolated from sourdough

Cited by 107 publications

References 19 publications

Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

Significance of pantothenate for glucose fermentation by Oenococcus oeni and for suppression of the erythritol and acetate production

Influence of calcium acetate on rye bread volume

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