Contribution of glutamate decarboxylase in Lactobacillus reuteri to acid resistance and persistence in sourdough fermentation

Su, Marcia Shu-Wei; Schlicht, Sabine; Gänzle, Michael G.

doi:10.1186/1475-2859-10-s1-s8

Cited by 110 publications

(114 citation statements)

References 43 publications

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“…L. reuteri 100-23, although a rodent isolate, ferments sourdough. As demonstrated by Su et al (23), addition of glutamate to a suspension of 100-23 cells in acidified phosphate buffer improved survival 100-fold relative to that in buffer alone. A strain mutated in the glutamate decarboxylase gene, a ⌬gadB strain, did not have improved survival.…”

Section: Discussionmentioning

confidence: 87%

Lactobacillus reuteri 100-23 Modulates Urea Hydrolysis in the Murine Stomach

Wilson

Loach

Lawley

et al. 2014

Appl Environ Microbiol

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cComparisons of in vivo (mouse stomach) and in vitro (laboratory culture) transcriptomes of Lactobacillus reuteri strain 100-23 were made by microarray analysis. These comparisons revealed the upregulation of genes associated with acid tolerance, including urease production, in the mouse stomach. Inactivation of the ureC gene reduced the acid tolerance of strain 100-23 in vitro, and the mutant was outcompeted by the wild type in the gut of ex-Lactobacillus-free mice. Urine analysis showed that stable isotope-labeled urea, administered by gavage, was metabolized to a greater extent in Lactobacillus-free mice than animals colonized by strain 100-23. This surprising observation was associated with higher levels of urease activity and fecal-type bacteria in the stomach digesta of Lactobacillus-free mice. Despite the modulation of urea hydrolysis in the stomach, recycling of urea nitrogen in the murine host was not affected since the essential amino acid isoleucine, labeled with a stable isotope, was detected in the livers of both Lactobacillus-free and 100-23-colonized animals. Therefore, our experiments reveal a new and unexpected impact of Lactobacillus colonization on urea hydrolysis in the murine gut.

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Section: Discussionmentioning

confidence: 87%

Lactobacillus reuteri 100-23 Modulates Urea Hydrolysis in the Murine Stomach

Wilson

Loach

Lawley

et al. 2014

Appl Environ Microbiol

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“…A study by Yokoyama et al (2002) explains the use of L. brevis IFO-12005 for the production of γ-aminobutyric acid from the residue of alcohol distillery. Recently, a study has reported that L. reuteri 100-23 play a role in acid resistance during fermentation owing to the production of GAD (Su et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Screening and kinetics of glutaminase and glutamate decarboxylase producing lactic acid bacteria from fermented Thai foods

Woraharn¹,

Lailerd²,

Sivamaruthi³

et al. 2014

Food Sci. Technol (Campinas)

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L-glutaminase and glutamic acid decarboxylase (GAD) catalyzes the hydrolysis of L-glutamine and glutamate, respectively. L-glutaminase widely used in cancer therapy along with a combination of other enzymes and most importantly these enzymes were used in food industries, as a major catalyst of bioconversion. The current investigation was aimed to screen and select L-glutaminase, and GAD producing lactic acid bacteria (LAB). A total of 338 LAB were isolated from fermented meat, fermented fish, fermented soya bean, fermented vegetables and fruits. Among 338 isolates, 22 and 237 LAB has been found to be positive for L-glutaminase and GAD, respectively. We found that 30 days of incubation at 35 ºC and pH 6.0 was the optimum condition for glutaminase activity by G507/1. G254/2 was found to be the best for GAD activity with the optimum condition of pH 6.5, temperature 40 ºC and ten days of incubation. These LAB strains, G507/1 and G254/2, were identified as close relative of Lactobacillus brevis ATCC 14869 and Lactobacillus fermentum NBRC 3956, respectively by 16S rRNA sequencing. Further, improvements in up-stream of the fermentation process with these LAB strains are currently under development.Keywords: L-glutaminase; glutamic acid decarboxylase; lactic acid bacteria and 16S rRNA sequencing.Practical Application: LABs based safe starter culture for the fermentation of mushroom to produce high GABA.

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“…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). The elevated temperatures, long fermentation times, and high water content select for thermophilic and acid-resistant organisms (9,11,12). L. reuteri prevails in type I and type II sourdoughs fermented at elevated temperatures (2,4,5).…”

mentioning

confidence: 99%

“…Strains of L. reuteri have evolved into phylogenetically distinct and host-adapted lineages (13), with lineage-specific metabolic and genetic traits reflecting adaptation to different hosts (14). Some rodent-lineage strains are acid resistant due to the presence of the glutamate decarboxylase GadB (12,15). Human-lineage strains convert glycerol or 1,2-propanediol to regenerate NAD ϩ (14,16,17).…”

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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Contribution of glutamate decarboxylase in Lactobacillus reuteri to acid resistance and persistence in sourdough fermentation

Cited by 110 publications

References 43 publications

Lactobacillus reuteri 100-23 Modulates Urea Hydrolysis in the Murine Stomach

Lactobacillus reuteri 100-23 Modulates Urea Hydrolysis in the Murine Stomach

Screening and kinetics of glutaminase and glutamate decarboxylase producing lactic acid bacteria from fermented Thai foods

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

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