scholarly journals Taxonomic Structure and Monitoring of the Dominant Population of Lactic Acid Bacteria during Wheat Flour Sourdough Type I Propagation Using Lactobacillus sanfranciscensis Starters

2008 ◽  
Vol 75 (4) ◽  
pp. 1099-1109 ◽  
Author(s):  
Sonya Siragusa ◽  
Raffaella Di Cagno ◽  
Danilo Ercolini ◽  
Fabio Minervini ◽  
Marco Gobbetti ◽  
...  

ABSTRACTThe structure and stability of the dominant lactic acid bacterium population were assessed during wheat flour sourdough type I propagation by using singly nine strains ofLactobacillus sanfranciscensis. Under back-slopping propagation with wheat flour type 0 F114, cell numbers of presumptive lactic acid bacteria varied slightly between and within starters. As determined by randomly amplified polymorphic DNA-PCR and restriction endonuclease analysis-pulsed-field gel electrophoresis analyses, only three (LS8, LS14, and LS44) starters dominated throughout 10 days of propagation. The others progressively decreased to less than 3 log CFU g−1. Partial sequence analysis of the 16S rRNA andrecAgenes and PCR-denaturating gradient gel electrophoresis analysis using therpoBgene allowed identification ofWeissella confusa,Lactobacillus sanfranciscensis,Lactobacillus plantarum,Lactobacillus rossiae,Lactobacillus brevis,Lactococcus lactissubsp.lactis,Pediococcus pentosaceus, andLactobacillusspp. as the dominant species of the raw wheat flour. At the end of propagation, one autochthonous strain ofL. sanfranciscensiswas found in all the sourdoughs. Except forL. brevis, strains of the above species were variously found in the mature sourdoughs. Persistent starters were found in association with other biotypes ofL. sanfranciscensisand withW. confusaorL. plantarum. Sourdoughs were characterized for acidification, quotient of fermentation, free amino acids, and community-level catabolic profiles by USING Biolog 96-well Eco microplates. In particular, catabolic profiles of sourdoughs containing persistent starters behaved similarly and were clearly differentiated from the others. The three persistent starters were further used for the production of sourdoughs and propagated by using another wheat flour whose lactic acid bacterium population in part differed from the previous one. Also, in this case all three starter strains persisted during propagation.

2012 ◽  
Vol 78 (15) ◽  
pp. 5328-5340 ◽  
Author(s):  
Fabio Minervini ◽  
Anna Lattanzi ◽  
Maria De Angelis ◽  
Raffaella Di Cagno ◽  
Marco Gobbetti

ABSTRACTSeven mature type I sourdoughs were comparatively back-slopped (80 days) at artisan bakery and laboratory levels under constant technology parameters. The cell density of presumptive lactic acid bacteria and related biochemical features were not affected by the environment of propagation. On the contrary, the number of yeasts markedly decreased from artisan bakery to laboratory propagation. During late laboratory propagation, denaturing gradient gel electrophoresis (DGGE) showed that the DNA band corresponding toSaccharomyces cerevisiaewas no longer detectable in several sourdoughs. Twelve species of lactic acid bacteria were variously identified through a culture-dependent approach. All sourdoughs harbored a certain number of species and strains, which were dominant throughout time and, in several cases, varied depending on the environment of propagation. As shown by statistical permutation analysis, the lactic acid bacterium populations differed among sourdoughs propagated at artisan bakery and laboratory levels.Lactobacillus plantarum,Lactobacillus sakei, andWeissella cibariadominated in only some sourdoughs back-slopped at artisan bakeries, andLeuconostoc citreumseemed to be more persistent under laboratory conditions. Strains ofLactobacillus sanfranciscensiswere indifferently found in some sourdoughs. Together with the other stable species and strains, other lactic acid bacteria temporarily contaminated the sourdoughs and largely differed between artisan bakery and laboratory levels. The environment of propagation has an undoubted influence on the composition of sourdough yeast and lactic acid bacterium microbiotas.


2001 ◽  
Vol 68 (1) ◽  
pp. 139-144 ◽  
Author(s):  
GIUSEPPE BLAIOTTA ◽  
GIANCARLO MOSCHETTI ◽  
ERMENEGILDA SIMEOLI ◽  
ROSAMARIA ANDOLFI ◽  
FRANCESCO VILLANI ◽  
...  

Lactic acid bacteria (LAB) play an important role in food fermentation, as the products obtained with their aid are characterized by hygienic safety, storage stability and attractive sensory properties. A major aim of the research in this field is the selection of LAB strains that could be used. Hence it is very important to be able to apply a reliable method to distinguish a particular strain specifically and unambiguously, which allows studies of population dynamics of mixed cultures and monitoring starter strains during fermentation (Ramos & Harlander, 1990).Molecular methods are a powerful alternative to the traditional differentiation of bacteria. A highly reproducible method for characterizing and distinguishing closely related strains, is represented by REA-PFGE (restriction endonuclease analysis by pulsed-field gel electrophoresis) performed by infrequently cutting endonucleases. Genetic differentiation of strains in several species of LAB has been successfully performed by this technique (Moschetti et al. 1997; Villani et al. 1997) obtaining very clear and reproducible restriction patterns (Moschetti et al. 1998).In this study selected inoculated strains (lactococci or lactobacilli) were monitored by REA-PFGE during the whole process of water-buffalo ‘cacioricotta’ cheese-making. This product is a typical and traditional cheese in southern Italy produced from cow, goat, ewe or water-buffalo milk. The original technology of this preparation permits the recovery of whey proteins due to the high heat treatment of whole milk employed, allowing interesting yields to be achieved in terms of cheese. The use of starters is not common in traditional technology but low acid protection of the final product suggested the use of LAB as starter (Emaldi et al. 1987).


2002 ◽  
Vol 68 (12) ◽  
pp. 6193-6201 ◽  
Author(s):  
Maria De Angelis ◽  
Liberato Mariotti ◽  
Jone Rossi ◽  
Maurizio Servili ◽  
Patrick F. Fox ◽  
...  

ABSTRACT The cytoplasmic extracts of 70 strains of the most frequently isolated sourdough lactic acid bacteria were screened initially for arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) activities, which comprise the ADI (or arginine dihydrolase) pathway. Only obligately heterofermentative strains such as Lactobacillus sanfranciscensis CB1; Lactobacillus brevis AM1, AM8, and 10A; Lactobacillus hilgardii 51B; and Lactobacillus fructivorans DD3 and DA106 showed all three enzyme activities. Lactobacillus plantarum B14 did not show CK activity. L. sanfranciscensis CB1 showed the highest activities, and the three enzymes were purified from this microorganism to homogeneity by several chromatographic steps. ADI, OTC, and CK had apparent molecular masses of ca. 46, 39, and 37 kDa, respectively, and the pIs were in the range of 5.07 to 5.2. The OTCs, CKs, and especially ADIs were well adapted to pH (acidic, pH 3.5 to 4.5) and temperature (30 to 37°C) conditions which are usually found during sourdough fermentation. Internal peptide sequences of the three enzymes had the highest level of homology with ADI, OTC, and CK of Lactobacillus sakei. L. sanfranciscensis CB1 expressed the ADI pathway either on MAM broth containing 17 mM arginine or during sourdough fermentation with 1 to 43 mM added arginine. Two-dimensional electrophoresis showed that ADI, OTC, and CK were induced by factors of ca. 10, 4, and 2 in the whole-cell extract of cells grown in MAM broth containing 17 mM arginine compared to cells cultivated without arginine. Arginine catabolism in L. sanfranciscensis CB1 depended on the presence of a carbon source and arginine; glucose at up to ca. 54 mM did not exert an inhibitory effect, and the pH was not relevant for induction. The pH of sourdoughs fermented by L. sanfranciscensis CB1 was dependent on the amount of arginine added to the dough. A low supply of arginine (6 mM) during sourdough fermentation by L. sanfranciscensis CB1 enhanced cell growth, cell survival during storage at 7°C, and tolerance to acid environmental stress and favored the production of ornithine, which is an important precursor of crust aroma compounds.


1971 ◽  
Vol 34 (11) ◽  
pp. 521-525 ◽  
Author(s):  
J. R. Stamer ◽  
B. O. Stoyla ◽  
B. A. Dunckel

The effects of pH values and NaCl concentrations on the growth rates of five species of lactic acid bacteria commonly associated with the sauerkraut fermentation were determined in filter-sterilized cabbage juice. Growth rates of all cultures, with the exception of Pediococcus cerevisiae, were retarded by addition of salt, lower pH, or interaction of both pH and salt. Based upon lag and generation times, P. cerevisiae was the culture most tolerant to the pH and salt concentration employed, whereas Streptococcus faecalis was the most sensitive species. Of the heterofermentative cultures, Lactobacillus brevis was less subject to growth inhibition than Leuconostoc mesenteroides. Under conditions simulating those found during the initial phases of the sauerkraut fermentation (2.25% salt, pH 6.2), L. mesenteroides displayed the shortest lag and generation times of all cultures examined. This rapid growth rate coupled with a marked accelerated death rate may explain, in part, the reason this species is both the first to dominate and the first to die during the early phases of the sauerkraut fermentation. Although cabbage juice previously fermented by L. mesenteroides appears to inhibit growth of P. cerevisiae, it had no apparent inhibitory or stimulatory effects on the other cultures.


2015 ◽  
Vol 6 (4) ◽  
pp. 505-512 ◽  
Author(s):  
M. Yakovlieva ◽  
T. Tacheva ◽  
S. Mihaylova ◽  
R. Tropcheva ◽  
K. Trifonova ◽  
...  

In recent years, many authors have investigated the possible antidiabetic effect of lactic acid bacteria. Lactobacillus species constitute a major part of the lactic acid bacteria group and have been found to exhibit beneficial effects on the development of diabetes and its complications. In the current study, we investigated the effects of newly characterised Bulgarian Lactobacillus strains, Lactobacillus brevis 15 and Lactobacillus plantarum 13, on blood glucose levels and body weight of rats fed a fructose-enriched diet. An experiment was conducted over a period of 8 weeks with 24 2-month-old Wistar rats randomly assigned to receive a standard diet (Con, control group), fructose-enriched diet (Fr group), standard diet with probiotics given twice a week (Pro group), and fructose-enriched diet with probiotics given twice a week (Pro+Fr group). At the end of the experimental period, a statistically significant increase in body weight was observed in all experimental groups (P<0.0001). The highest rise was seen in the fructose group (Fr, 169±19 g), followed by the Pro+Fr group (153±15 g), Pro group (149±13 g), and Con group (141±5 g). Moreover, the final blood glucose levels had risen significantly in the groups receiving fructose either without (Fr; P<0.0001) or with lactobacilli (Pro+Fr; P=0.002), while the rise was insignificant in the group of rats given probiotic supplementation only (Pro, P=0.071) and inexistent in the Con group (P=0.999). The highest elevation of blood glucose levels was observed in the Fr group (3.18 mmol/l), followed by the Pro+Fr group (2.00 mmol/l) whereas the Pro group showed the lowest levels (0.60 mmol/l). The results of our study suggest that the newly characterised Bulgarian Lactobacillus strains, L. brevis 15 and L. plantarum 13, could be considered as possible probiotics and might be able to prevent some metabolic disturbances.


10.5219/1604 ◽  
2021 ◽  
Vol 15 ◽  
pp. 995-1004
Author(s):  
Aleš Vavřiník ◽  
Kateřina Štůsková ◽  
Adrian Alumbro ◽  
Methusela Perrocha ◽  
Lenka Sochorová ◽  
...  

The presented work aimed to study the inhibition using nanoparticles produced by the green synthesis in selected acetic acid and lactic acid bacteria, which are related to viticulture. The degree of ability to eliminate silver particles produced by green syntheses was determined using the plate method on Petri dishes. This is done using two different approaches - the method of direct application of the solution to the surface of the inoculated medium (determination of inhibition zones) and the method of application using nanoparticles to the inoculated medium. Gluconobacter oxydans (CCM 3618) and Acetobacter aceti (CCM 3620T) were studied from acet acetic bacteria. The lactic acid bacteria were Lactobacillus brevis (CCM 1815) and Pediococcus damnosus (CCM 2465). The application of silver nanoparticles was always in concentrations of 0, 0.0625, 0.125, 0.25, 0.5, and 1 g.L-1. All applied concentrations of silver nanoparticles showed an inhibitory effect on the monitored microorganisms. Silver particles could be used in wine technology for their antibacterial effects, mainly to inhibit microorganisms during vinification, as a substitute for sulfur dioxide.


2016 ◽  
Vol 33 (No. 5) ◽  
pp. 458-463 ◽  
Author(s):  
M. Magala ◽  
Z. Kohajdová ◽  
J. Karovičová ◽  
M. Greifová ◽  
J. Hojerová

We investigated the suitability of rice flour for fermented beverage production using various strains of lactic acid bacteria. Fermentation led to a decrease in pH from 5.04&ndash;5.17 to 3.74&ndash;4.35. At the same time, total acidity increased (1.28&ndash;2.59&nbsp;g/l) due to lactic acid (0.59&ndash;2.76 g/l) and acetic acid (0.11&ndash;0.30 g/l) production. Fermentation of rice beverages also caused a gradual decrease in glucose and fructose concentration. Lactic acid bacteria proliferated in the first phases of fermentation, and cell counts reached a maximum after 12 h. The highest growth rate (v<sub>LAB</sub> = 0.44 Log<sub>10</sub> CFU/ml/h) was observed in a sample with the culture of Lactobacillus brevis CCM 1815. Viscosity of beverages decreased significantly after 24&nbsp;h of fermentation. The highest values of sensory parameters were observed in a monoculture of Lactobacillus plantarum CCM 7039 and in a sample with a mixed culture of Lactobacillus plantarum CCM 7039 and Bifidobacterium longum CCM 4990.


2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Luchan Gong ◽  
Cong Ren ◽  
Yan Xu

ABSTRACT Lactic acid bacteria often encounter a variety of multiple stresses in their natural and industrial fermentation environments. The glutamate decarboxylase (GAD) system is one of the most important acid resistance systems in lactic acid bacteria. In this study, we demonstrated that GlnR, a nitrogen regulator in Gram-positive bacteria, directly modulated γ-aminobutyric acid (GABA) conversion from glutamate and was involved in glutamate-dependent acid resistance in Lactobacillus brevis. The glnR deletion strain (ΔglnR mutant) achieved a titer of 284.7 g/liter GABA, which is 9.8-fold higher than that of the wild-type strain. The cell survival of the glnR deletion strain was significantly higher than that of the wild-type strain under the condition of acid challenge and was positively correlated with initial glutamate concentration and GABA production. Quantitative reverse transcription-PCR assays demonstrated that GlnR inhibited the transcription of the glutamate decarboxylase-encoding gene (gadB), glutamate/GABA antiporter-encoding gene (gadC), glutamine synthetase-encoding gene (glnA), and specific transcriptional regulator-encoding gene (gadR) involved in gadCB operon regulation. Moreover, GABA production and glutamate-dependent acid resistance were absolutely abolished in the gadR glnR deletion strain. Electrophoretic mobility shift and DNase I footprinting assays revealed that GlnR directly bound to the 5′-untranslated regions of the gadR gene and gadCB operon, thus inhibiting their transcription. These results revealed a novel regulatory mechanism of GlnR on glutamate-dependent acid resistance in Lactobacillus. IMPORTANCE Free-living lactic acid bacteria often encounter acid stresses because of their organic acid-producing features. Several acid resistance mechanisms, such as the glutamate decarboxylase system, F1Fo-ATPase proton pump, and alkali production, are usually employed to relieve growth inhibition caused by acids. The glutamate decarboxylase system is vital for GAD-containing lactic acid bacteria to protect cells from DNA damage, enzyme inactivation, and product yield loss in acidic habitats. In this study, we found that a MerR-type regulator, GlnR, was involved in glutamate-dependent acid resistance by directly regulating the transcription of the gadR gene and gadCB operon, resulting in an inhibition of GABA conversion from glutamate in L. brevis. This study represents a novel mechanism for GlnR's regulation of glutamate-dependent acid resistance and also provides a simple and novel strategy to engineer Lactobacillus strains to elevate their acid resistance as well as GABA conversion from glutamate.


2007 ◽  
Vol 73 (22) ◽  
pp. 7283-7290 ◽  
Author(s):  
S. Siragusa ◽  
M. De Angelis ◽  
R. Di Cagno ◽  
C. G. Rizzello ◽  
R. Coda ◽  
...  

ABSTRACT The concentrations of γ-aminobutyric acid (GABA) in 22 Italian cheese varieties that differ in several technological traits markedly varied from 0.26 to 391 mg kg−1. Presumptive lactic acid bacteria were isolated from each cheese variety (total of 440 isolates) and screened for the capacity to synthesize GABA. Only 61 isolates showed this activity and were identified by partial sequencing of the 16S rRNA gene. Twelve species were found. Lactobacillus paracasei PF6, Lactobacillus delbrueckii subsp. bulgaricus PR1, Lactococcus lactis PU1, Lactobacillus plantarum C48, and Lactobacillus brevis PM17 were the best GABA-producing strains during fermentation of reconstituted skimmed milk. Except for L. plantarum C48, all these strains were isolated from cheeses with the highest concentrations of GABA. A core fragment of glutamate decarboxylase (GAD) DNA was isolated from L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48 by using primers based on two highly conserved regions of GAD. A PCR product of ca. 540 bp was found for all the strains. The amino acid sequences deduced from nucleotide sequence analysis showed 98, 99, 90, and 85% identity to GadB of L. plantarum WCFS1 for L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48, respectively. Except for L. lactis PU1, the three lactobacillus strains survived and synthesized GABA under simulated gastrointestinal conditions. The findings of this study provide a potential basis for exploiting selected cheese-related lactobacilli to develop health-promoting dairy products enriched in GABA.


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