Showing papers on "Leuconostoc published in 2003"
TL;DR: The differential distribution of species found suggests specific ecological reasons for the establishment of sites of actual microbial growth in the cheese, with implications of significance in understanding the ecology of food systems and with the aim of achieving optimization of the fermentation technologies as well as preservation of traditional products.
Abstract: The microbial diversity occurring in Stilton cheese was evaluated by 16S ribosomal DNA analysis with PCR-denaturing gradient gel electrophoresis. DNA templates for PCR experiments were directly extracted from the cheese as well as bulk cells harvested from a variety of viable-count media. The variable V3 and V4-V5 regions of the 16S genes were analyzed. Closest relatives of Lactococcus lactis, Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus curvatus, Leuconostoc mesenteroides, Staphylococcus equorum, and Staphylococcus sp. were identified by sequencing of the DGGE fragments. Fluorescently labeled oligonucleotide probes were developed to detect Lactococcus lactis, Lactobacillus plantarum, and Leuconostoc mesenteroides in fluorescence in situ hybridization (FISH) experiments, and their specificity for the species occurring in the community of Stilton cheese was checked in FISH experiments carried out with reference cultures. The combined use of these probes and the bacterial probe Eub338 in FISH experiments on Stilton cheese sections allowed the assessment of the spatial distribution of the different microbial species in the dairy matrix. Microbial colonies of bacteria showed a differential location in the different parts of the cheese examined: the core, the veins, and the crust. Lactococci were found in the internal part of the veins as mixed colonies and as single colonies within the core. Lactobacillus plantarum was detected only underneath the surface, while Leuconostoc microcolonies were homogeneously distributed in all parts observed. The combined molecular approach is shown to be useful to simultaneously describe the structure and location of the bacterial flora in cheese. The differential distribution of species found suggests specific ecological reasons for the establishment of sites of actual microbial growth in the cheese, with implications of significance in understanding the ecology of food systems and with the aim of achieving optimization of the fermentation technologies as well as preservation of traditional products.
280 citations
TL;DR: One hundred and thirteen strains of lactic acid bacteria (LAB) were selected from 351 isolates from 15 samples of traditionally fermented household bushera from Uganda and also from laboratory-preparedBushera using API 50 CHL kits and additional biochemical tests to assess their ability to ferment 49 carbohydrates.
279 citations
TL;DR: The potential to produce the biogenic amines tyramine, histamine and putrescine, was investigated for lactic acid bacteria of various origin, including commercial malolactic starter cultures, type strains and 78 strains isolated from Spanish grape must and wine.
250 citations
TL;DR: Folate production was further investigated in L. lactis as a model organism for metabolic engineering and in S. thermophilus for direct translation to (dairy) applications, and an inverse relationship was observed between growth rate and folate production.
Abstract: A variety of lactic acid bacteria were screened for their ability to produce folate intracellularly and/or extracellularly. Lactococcus lactis, Streptococcus thermophilus, and Leuconostoc spp. all produced folate, while most Lactobacillus spp., with the exception of Lactobacillus plantarum, were not able to produce folate. Folate production was further investigated in L. lactis as a model organism for metabolic engineering and in S. thermophilus for direct translation to (dairy) applications. For both these two lactic acid bacteria, an inverse relationship was observed between growth rate and folate production. When cultures were grown at inhibitory concentrations of antibiotics or salt or when the bacteria were subjected to low growth rates in chemostat cultures, folate levels in the cultures were increased relative to cell mass and (lactic) acid production. S. thermophilus excreted more folate than L. lactis, presumably as a result of differences in the number of glutamyl residues of the folate produced. In S. thermophilus 5,10-methenyl and 5-formyl tetrahydrofolate were detected as the major folate derivatives, both containing three glutamyl residues, while in L. lactis 5,10-methenyl and 10-formyl tetrahydrofolate were found, both with either four, five, or six glutamyl residues. Excretion of folate was stimulated at lower pH in S. thermophilus, but pH had no effect on folate excretion by L. lactis. Finally, several environmental parameters that influence folate production in these lactic acid bacteria were observed; high external pH increased folate production and the addition of p-aminobenzoic acid stimulated folate production, while high tyrosine concentrations led to decreased folate biosynthesis.
221 citations
TL;DR: The present study, the first to fully document rice-associated LAB, showed a very diverse community of LAB with a relatively high number of species involved in the fermentation process of paddy rice silage and enabling the future design of appropriate inoculants aimed at improving its fermentation quality.
Abstract: A total of 161 low-G+C-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical characters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Weissella. Analysis of the 16S ribosomal DNA (rDNA) was used to confirm the presence of the predominant groups indicated by phenotypic analysis and to determine the phylogenetic affiliation of representative strains. The virtually complete 16S rRNA gene was PCR amplified and sequenced. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank reference strains (between 98.7 and 99.8%). Phylogenetic trees based on the 16S rDNA sequence displayed high consistency, with nodes supported by high bootstrap values. With the exception of one species, the genetic data was in agreement with the phenotypic identification. The prevalent LAB, predominantly homofermentative (66%), consisted of Lactobacillus plantarum (24%), Lactococcus lactis (22%), Leuconostoc pseudomesenteroides (20%), Pediococcus acidilactici (11%), Lactobacillus brevis (11%), Enterococcus faecalis (7%), Weissella kimchii (3%), and Pediococcus pentosaceus (2%). The present study, the first to fully document rice-associated LAB, showed a very diverse community of LAB with a relatively high number of species involved in the fermentation process of paddy rice silage. The comprehensive 16S rDNA-based approach to describing LAB community structure was valuable in revealing the large diversity of bacteria inhabiting paddy rice silage and enabling the future design of appropriate inoculants aimed at improving its fermentation quality.
199 citations
TL;DR: In three different dairies located in Peloponess region (Southern Greece), traditional Feta cheese trials took place February to March using mixtures of sheep's and goat's milk, and only small variations in the evolution of microbial groups were observed during the whole ripening period.
197 citations
TL;DR: A sequential use of the three enzymes is proposed to simplify LAB wine identification, first MseI, then BfaI and finally, if necessary, AluI digestion, able to discriminate 32 of the 36 LAB reference species tested and allowed the identification of 342 isolates from musts and wines.
182 citations
TL;DR: The results presented demonstrate that Leuc.
152 citations
TL;DR: In this article, 30 lactic acid bacteria (LAB) isolated from Armada cheese, Sobado variety, were screened for their acidifying capacity and enzymatic activity, that included the rapid API-ZYM system, the proteolytic activity, amino-, di-, and carboxypeptidase activity and the caseinolytic activity.
128 citations
TL;DR: The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.
Abstract: Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.
TL;DR: Enterococcus faecium strain EK13 isolated from cattle dung water produces two bacteriocins, enterocin A and P, with an inhibitory effect against the strain of the genera Enterococcus, Leuconostoc, Lactobacillus, Streptococcus and Listeria (in different origin).
Abstract: Aims: The partial characterization of bacteriocins produced by an environmental strain Enterococcus faecium EK13, isolated from cattle dung water.
Methods and Results: A bacteriocin was partially purified by ammonium sulphate precipitation, followed by a SP-Sepharose column, reverse-phase chromatography and N-terminal region sequenced. The anti-microbial substance produced was found to be a heat-stable polypeptide with molecular mass 4·83 kDa, which was determined by N-terminal amino acid sequencing to be enterocin A. A second substance was specified by PCR as enterocin P. Bacteriocins were stable at 4 and −20°C for long storage periods. The optimum of bacteriocin production was observed in the range of pH 5·0–6·5 at 30 and 37°C. The most active substances are produced by strain EK13 in logarithmic growth phase and bacteriocins are produced after 1 h of fermentation. The highest activity detected in fermentation experiments was 51 200 AU ml−1 and the most sensitive indicator strain was found to be Listeria innocua LMG 13568. Differences in bacteriocin activity against two indicators could be explained by more than one type of enterocin production by strain EK13, or with different mode of action or in different sensitivity of strains.
Conclusion:Enterococcus faecium strain EK13 isolated from cattle dung water produces two bacteriocins, enterocin A and P, with an inhibitory effect against the strain of the genera Enterococcus, Leuconostoc, Lactobacillus, Streptococcus, Staphylococcus, Bacillus and Listeria (in different origin).
Significance and Impact of the Study:Enterococcus faecium EK13 environmental strain is a new producer of enterocin A and P. The E. faecium EK13, isolated from cattle dung water, is presented with the further aim to utilize it for waste treatment by biotechnological processes.
TL;DR: The gene coding for inulosucrase in Leuconostoc citreum CW28, islA, was cloned, sequenced, and expressed in Escherichia coli and it was found that this fructosyltransferase is a natural chimeric enzyme resulting from the substitution of the catalytic domain of alternansucrase by a fructan binding domain.
Abstract: The gene coding for inulosucrase in Leuconostoc citreum CW28, islA, was cloned, sequenced, and expressed in Escherichia coli. The recombinant enzyme catalyzed inulin synthesis from sucrose like the wild-type enzyme. Inulosucrase presents an unusual structure: its N-terminal region is similar to the variable region of glucosyltransferases, its catalytic domain is similar to fructosyltransferases from various microorganisms, and its C-terminal domain presents similarity to the glucan binding domain from alternansucrase, a glucosyltransferase from Leuconostoc mesenteroides NRRL B-1355. From sequence comparison, it was found that this fructosyltransferase is a natural chimeric enzyme resulting from the substitution of the catalytic domain of alternansucrase by a fructosyltransferase. Two different forms of the islA gene truncated in the C-terminal glucan binding domain were successfully expressed in E. coli and retained their ability to synthesize inulin but lost thermal stability. This is the first report of an inulosucrase bearing structural features of both glucosyltransferases and fructosyltransferases.
TL;DR: The practical use of the bacteriocin producing Leuconostoc carnosum 4010 is optimized in order to inhibit the growth of Listeria monocytogenes in sliced meat products.
Abstract: T . J A C O B S E N , B . B . B U D D E A N D A . G . K O C H . 2003. Aims: To optimize the practical use of the bacteriocin producing Leuconostoc carnosum 4010 in order to inhibit the growth of Listeria monocytogenes in sliced meat products. Methods and Results: Four different methods for biopreservation using the partially purified bacteriocin or the living culture of Leuc. carnosum 4010 were evaluated. The methods using the living protective culture added to the sliced gas packed meat product were more effective in preventing growth of L. monocytogenes than the use of the partially purified leucocins 4010 or bacteriocin produced during fermentation before heat treatment of the saveloy. The application method giving the highest reduction in L. monocytogenes used nozzles for sprinkling the protective culture on all surfaces of each slice of the meat product. In the control samples without the protective culture, L. monocytogenes grew to ca .1 0 7 CFU g )1 , whereas for the application method using nozzles for distributing the protective culture, counts of L. monocytogenes never exceeded 10 CFU g )1 during 4 weeks of storage at 10� C. Conclusions: The live cells of the bacteriocin producing Leuc. carnosum 4010 was the most efficient method as it inhibited the growth of L. monocytogenes in cooked, sliced and gas packed saveloy stored at 5 and 10� C for 4 weeks. Significance and Impact of the Study: The results indicate that biopreservation with lactic acid bacteria is a suitable alternative to chemical preservatives. An even distribution of the protective culture was found to be essential for the efficacy of the protective culture in pilot plant trials.
TL;DR: Although the bacteria were initially below the detection limit in model cooked meat products, the bacterial counts increased to 108 CFU/g at 10°C after 7 to 12 days.
Abstract: Three kinds of lactic acid bacteria were isolated from spoiling cooked meat products stored below 10°C. They were identified as Leuconostoc mesenteroides subsp. mesenteroides, Lactococcus lactis subsp. lactis, and Leuconostoc citreum. All three strains grew well in MRS broth at 10°C. In particular, L. mesenteroides subsp. mesenteroides and L. citreum grew even at 4°C, and their doubling times were 23.6 and 51.5 h, respectively. On the other hand, although the bacteria were initially below the detection limit (<10 CFU/g) in model cooked meat products, the bacterial counts increased to 108 CFU/g at 10°C after 7 to 12 days.
TL;DR: To screen bacteriocin‐producing lactic acid bacteria (LAB) in 52 type and reference strains, which have not previously been studied, with respect to bacteriaiocins, and to characterize the presence of bacteriOCins.
Abstract: Aims: To screen bacteriocin-producing lactic acid bacteria (LAB) in 52 type and reference strains, which have not previously been studied, with respect to bacteriocins, and to characterize the presence of bacteriocins.
Methods and Results: Only Enterococcus faecium JCM 5804T showed bacteriocin-like activity. It inhibited the growth of Lactobacillus spp., Enterococcus spp., Clostridium spp., Listeria monocytogenes, and vancomycin resistant Enterococcus (VRE). However, it was not effective against Gram-negative strains, Weisella spp., Leuconostoc spp., Lactococcus spp., or methicillin resistant Staphylococcus aureus (MRSA). The inhibitory activity of Ent. faecium JCM 5804T was inactivated by proteinase K, trypsin, α-chymotrypsin, and papain, but not by lysozyme, lipase, catalase, or β-glucosidase. The inhibitory activity was stable at 100°C for 30 min, and had a pH range from 2 to 10. The molecular weight of the partially purified bacteriocin(s) was approx. 4·5 kDa, according to tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Polymerase chain reaction and direct sequencing methods identified three different types of bacteriocins produced by Ent. faecium JCM 5804T, enterocin A, enterocin B, and enterocin P-like bacteriocin.
Conclusion:Enterococcus faecium JCM 5804T produced three different types of bacteriocins, and they inhibited LAB and pathogens.
Significance and Impact of Study: This is the first report of enterocin A, enterocin B, and enterocin P-like bacteriocin, detected in Ent. faecium JCM 5804T among LAB type and reference strains.
TL;DR: Despite the high LAB numbers detected, radical spoilage changes such as unpleasant odor, slime production and formation of gas were not seen and B. thermosphacta did not form a significant part of the bacterial population since none of the levels exceeded the spoilage threshold level of 10(5) CFU/g reported in previous studies for this organism.
TL;DR: Ribosomal DNA-based techniques including the analysis of profiles generated by ISR amplification, ISR restriction and ARDRA have been evaluated as molecular tools for identifying Carnobacterium, Lactobacillus, Leuconostoc and Pediococcus and can be considered useful for taxonomic purposes.
TL;DR: A study about the effect of phosphate concentration on cell propagation in a semicontinuous shake-flask culture is described, and an increase on biomass and on the enzyme activity was found when phosphate enriched medium was used.
Abstract: Leuconostoc mesenteroides NRRL B512F is the main strain used in industrial fermentations to produce dextransucrase and dextran. This process has been studied since the Second World War, when it was used as blood plasma expander. A study about the effect of phosphate concentration on cell propagation in a semicontinuous shake-flask culture is described in this work. Dextransucrase is obtained by fermentation of the Leuconostoc mesenteroides NRRL B512F in the presence of sucrose as substrate, a nitrogen source (corn liquor or yeast extract) and minerals. Phosphate is currently used in order to buffer the culture medium. Cell propagation can be done through a repeated batch culture, where dilution in a fresh medium is made with relatively short periods. The standard medium for dextransucrase production is prepared using 0.1 M of K(2)HPO(4). In this work the level of phosphate was increased to 0.3 M, and an increase on biomass and on the enzyme activity was found when phosphate enriched medium was used. Higher phosphate buffer concentration was also able to keep the pH values above 5.0 during the entire process, avoiding enzyme denaturation.
TL;DR: The results show that dextransucrase can be efficiently expressed and secreted in a non-Leuconostoc, heterologous host and is able to drive dextran synthesis.
Abstract: The gene encoding the dextransucrase DsrD from the industrial strain Leuconostoc mesenteroides Lcc4 was isolated by PCR using degenerate primers recognizing conserved regions present in other dextransucrase-encoding genes from Leuconostoc spp. and Southern blot analyses on total genomic DNA. N-terminal sequence analysis of the active protein recovered in the culture showed that the secreted protein of 165 kDa is devoid of a 42 aa prepeptide which is removed post-translationally, most likely by signal peptidase cleavage. Primer extension and Northern blot analysis identified a monocistronic dsrD mRNA with two transcription initiation sites. Expression of the dextransucrase DsrD was investigated in pH-controlled fed-batch cultures via Northern blot analysis and enzyme activity measurement during the experiments. Sucrose levels of 20 g l−1 were shown to induce the DsrD biosynthesis around 10-fold. The combination of pH-controlled fed-batch fermentation and Northern analysis clearly showed that dsrD expression was related to the growth of the bacteria. dsrD was transferred to and expressed in Lactococcus lactis MG1363. Controlled fed-batch cultures revealed that active dextransucrase was produced and secreted by the recombinant L. lactis strain. The expression was independent of sucrose levels. These results show that dextransucrase can be efficiently expressed and secreted in a non-Leuconostoc, heterologous host and is able to drive dextran synthesis.
TL;DR: Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various Lactobacilli strains.
Abstract: Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus. Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate primers based on homologous boxes of known glucosyltransferase (gtf) genes of lactic acid bacteria strains allowed cloning of fragments of 10 putative gtf genes from eight different glucan producing Lactobacillus strains (five Lactobacillus reuteri strains, one Lactobacillus fermentum strain, one Lactobacillus sake strain and one Lactobacillus parabuchneri strain). Sequence analysis revealed that these lactobacilli possess a large variation of (putative) gtf genes, similar to what has been observed for Leuconostoc and Streptococcus strains. Homologs of GTFA of Lb. reuteri 121 (synthesizing reuteran, a unique glucan with α(1 → 4) and α-(1 → 6) glycosidic bonds) (Kralj et al., 2002) were found in three of the four other Lb. reuteri strains tested. The other Lactobacillus GTF fragments showed the highest similarity with GTF enzymes of Leuconostoc spp.
TL;DR: This PCR-RFLP method enables the rapid and reliable identification of Leuconostoc species and to distinguish them from the other phylogenetically related lactic acid bacteria in food samples.
Journal Article•
TL;DR: Based on results, pediocin PD-1 effectively inhibited the growth of O. oeni and may provide an alternative to chemical preservatives.
Abstract: While malolactic bacteria are known to stabilize wine and change its organoleptic properties, uncontrolled malolactic fermentation may cause spoilage. Use of SO2 to inhibit microbial growth is strictly regulated, and demands for safe alternatives to chemical preservatives has led to increased interest in natural antimicrobial substances. Pediocin PD-1, an antimicrobial peptide produced by Pediococcus damnosus NCFB 1832, is active against a number of lactic acid bacteria, including malolactic strains of Lactobacillus, Leuconostoc , and Oenococcus spp. Antimicrobial activity of pediocin PD-1 remained constant (1600 AU/mL) for 28 days in dry-fermented (yeast fermented) grape must adjusted to pH 3 and 4, respectively. However, antimicrobial activity decreased to 800 and 600 AU/mL after 48 hr in the same must when adjusted to pH 6 and 7, respectively. A complete loss in antimicrobial activity was recorded after 48 hr of incubation in grape must with a pH of 8 or 9. No change in antimicrobial activity was detected when pediocin PD-1 was incubated in must containing 15% (v/v) ethanol, 100 mg/L SO2, or a combination thereof. When Oenococcus oeni was cultured in Chardonnay must (pH 3.8) and must supplemented with yeast extract (pH 3.8) the viable cell numbers of O. oeni decreased from 1 x 106 cfu/mL to less than 10 CFU/mL after 4 days of incubation in the presence of 30 AU/mL pediocin PD-1. Pediocin PD-1 did not inhibit the growth of a commercial starter culture strain of Saccharomyces cerevisiae or a mutant with an impaired cell wall structure caused by deletion of the CWP2 gene (Δ cwp2 ). Based on results, pediocin PD-1 effectively inhibited the growth of O. oeni and may provide an alternative to chemical preservatives.
TL;DR: One hundred and thirty lactic acid bacteria (Lactococcus, Lactobacillus and Leuconostoc), isolated from Tenerife cheese, were technologically characterized, finding interesting differences within genera, species and strains.
Abstract: Summary One hundred and thirty lactic acid bacteria (Lactococcus, Lactobacillus and Leuconostoc), isolated from Tenerife cheese, were technologically characterized. Interesting differences within genera, species and strains were found. None of the strains showed lipolytic activity on tributyrin agar while the majority exhibited proteolytic activity on calcium caseinate agar. Citrate was metabolized exclusively by 98.3% of the lactobacilli isolates. Lactococcus lactis ssp. lactis showed the highest acidifying and proteolytic activities in milk, although considerable inter-strain variations were found. Lactobacilli had the highest aminopeptidolytic activity. Dipeptidase activity was displayed by most lactic acid bacteria isolates with the higher specific activity exhibited by Lc. lactis ssp. lactis strains. Leuconostoc isolates had the highest esterolytic and β-galactosidase activity.
Journal Article•
TL;DR: The composition of lactic acid population in five kinds of seafood packaged in two different modified atmospheres, MAP1 and MAP2, represents the prevalent microbial group, especially in tuna, shrimps and sword- fish, whereas MAP2 seems to favour Lactobacillus spp.
Abstract: The composition of lactic acid population in five kinds of seafood (salmon, tuna, shrimps, swordfish and cuttlefish) packaged in two different modified atmospheres, MAP1 (80 O 2 /20 N 2 ) and MAP2 (40 CO 2 /60 N 2 ), at 4 °C for 6 days was investigated. The isolates were heterofermentative rods belonging to Carnobacterium, Lactobacillus, and cocci of the Leuconostoc genus. The determination of phenotypical characters and a new polymerase chain reaction primer were used to distinguish Carnobacterium from Lacto- bacillus. The microorganisms found varied with the kind of seafood and the gas composi- tion of the modified atmospheres: in MAP1, richer of oxygen than MAP2, Carnobacte- rium spp. represents the prevalent microbial group, especially in tuna, shrimps and sword- fish, whereas MAP2 seems to favour Lactobacillus spp. Cocci, belonging to Leuconostoc spp., were dominant in salmon and cuttlefish independently of gas composition.
TL;DR: During the storage of boza the total number of the lactic acid bacteria increased slightly up to 48 h, while the number of yeasts increased considerably, in accordance with the changes in viable count of lactic Acid bacteria and their activity.
Abstract: A total of 293 strains of lactic acid bacteria and 78 yeast strains from original Bulgarian boza were isolated. The rod-shaped strains were identified as Lactobacillus salivarius, Lactobacillus sakei, Lactobacillus maltaromicus, Lactobacillus fermentum, Lactobacillus parabuchneri, Lactobacillus paracasei subsp. paracasei and Weissella confusa. The strains of genus Leuconostoc were identified as Leuconostoc lactis, Leuconostoc amelibiosum, Leuconostoc mesenteroides subsp. dextranicum and Leuconostoc pseuclomesenteroides. The yeasts isolated belonged to the species Saccharomyces cerevisiae, Pichia membranifaciens, Dekkera bruxellensis and Nadsonici commutata. During the storage of boza the total number of the lactic acid bacteria increased slightly up to 48 h, while the n umber of yeasts increased considerably. The changes in pH and total acidity during the storage of boza were in accordance with the changes in viable count of lactic acid bacteria and their activity.
TL;DR: This review deals with culture media for the detection, selective isolation and cultivation of different groups of lactic acid bacteria (LAB) and suggests a need for a suitable medium for testing susceptibility to antibiotics.
Abstract: This review deals with culture media for the detection, selective isolation and cultivation of different groups of lactic acid bacteria (LAB). Numerous elective and semi-selective media are available and currently used for LAB. Most of them have been developed to isolate certain groups of LAB from a specific habitat, such as meat or dairy products. These media can be rendered more selective by the addition of specific inhibitory agents or by reducing the pH. Members of the genera Lactobacillus, Leuconostoc, Pediococcus and Weissella (so-called LLPW group) share a number of physiological similarities and generally respond in the same way to conditions or compounds inhibitory to non-LAB. Therefore, most culture media developed for the detection of Lactobacillus or Leuconostoc are not completely selective for the respective genus. Carnobacteria can easily be distinguished from the LLPW group by their non-aciduric nature. However, because of physiological similarities to the genus Enterococcus, such as ability to grow at pH values up to 9.5, media developed for the selective isolation of Carnobacterium do not suppress growth of enterococci which often share the same habitat. Several useful selective media are available for beer pediococci, Tetragenococcus and Oenococcus, organisms characterised by specific properties associated with their adaptation to special environments. Because of the growing interest in probiotic strains and the inhabitants of the intestine, many media have been proposed in recent years for selective isolation of particular species or strains from those habitats, typically containing mixed populations of different LAB. Similarily, the increasing attention to safety aspects of LAB used as starter or probiotic cultures has emphasised the need for the development of a suitable medium for testing susceptibility to antibiotics.
Journal Article•
TL;DR: Leuconostoc sp.
Abstract: Infections by Leuconostoc species bacteria are uncommon, and usually affect patients with an underlying disease, or those fitted with a venous catheter or subjects previously treated with vancomycin. The most common clinical presentation is fever secondary to a central venous line infection. We report a case of Leuconostoc sp. bacteremia in an otherwise apparently healthy 2.5 month-old infant. The patient was successfully treated with cefotaxime. Leuconostoc sp. is an emerging pathogen that should be considered in the differential diagnosis of vancomycin-resistant Gram-positive bacteremia.
01 Jan 2003
TL;DR: In this article, the authors investigated the isolation, identification and antibacterial activity of lactic acid bacteria related to Kimchi fermentation and found that the results did not coincide in several cases, however, their results did coincide in some cases, such as Leuconostoc mesenteriodes, Leu. carnosum, Lactobacillus curvatus, Lac. Leu, Weissela kimchi, W. cibaria, and Pediococcus pentosaceus.
Abstract: This study was carried out to investigate the isolation, identification , and antibacterial activity of lactic acid bacteria related to Kimchi fermentation. Diluted kimchi soup was plated on the MRS agar media with CaCo©u and incubated at 25iE for 2 days . A total of 27 strains of lactic acid bacteria from various indigenous, spontaneously fermented vegetables were isolated. Combined methods of Bergey's manual of systematic bacteriology, BPB media analysis and 16S rDAN sequence analysis were applied for identification, however, their results did dnot coincide in several cases. Isolated lactic acid bacteria could be classified by the 16S rDNA sequence analysis as Leuconostoc mesenteriodes, Leu. carnosum, Lactobacillus curvatus, Lac. pentosus, Weissela kimchi, W. cibaria, and Pediococcus pentosaceus. Leu. carnosum has not been reported in kimchi lactic acid bacteria