Weissella Hellenica Research Articles

Identification and characterization of lactic acid bacteria isolated from mixed pasture of timothy and orchardgrass, and its badly preserved silage

In order to understand the relationship between lactic acid bacteria (LAB) species and silage fermentation, a total of 65 LAB strains isolated from mixed pasture of timothy (Phleum pratense L.) and orchardgrass (Dactylis glomerata L.), and its badly preserved silages were subjected to phenotypic and genetic analysis. According to these analyses, the isolates were divided into 13 groups, including Enterococcus gallinarum, Lactobacillus acidipiscis, L. coryniformis subsp. coryniformis, L. coryniformis subsp. torquens, L. curvatus, L. paraplantarum, L. plantarum subsp. argentoratensis, L. plantarum subsp. plantarum, L. sakei subsp. carnosus, Lactococcus garvieae, Lactococcus lactis subsp. cremoris, Leuconostoc pseudomesenteroides, Pediococcus acidilactici, Pediococcus pentosaceus, Weissella hellenica, Weissella paramesenteroides and Carnobacterium divergens. This is the first report to document that C. divergens, L. acidipiscis, L. sakei subsp. carnosus, L. garvieae, phenotypically novel L. lactis subsp. cremoris, E. gallinarum and W. hellenica are present in vegetative forage crops. L. plantarum group strains were most frequently isolated from the badly preserved silages. Some isolates showed a wide range of growth preferences for carbohydrate utilization, optimal growth pH and temperature in vitro, indicating that they have a high growth potential. These results are useful in understanding the diversity of LAB associated with decayed silage of timothy and orchardgrass.

Characterization of the dominant microflora in naturally fermented camel milk shubat

This study aimed to characterize the dominant microflora in shubat, a special fermented product prepared from unheated two-humped camel milk. In the seven investigated samples of shubat, lactic acid bacteria and yeasts were the dominant microorganisms with the number ranging from log 6.8 to 7.6 cfu/ml and from log 4.3 to 4.7 cfu/ml, respectively. Using phenotypic and molecular methods, a total of 48 LAB isolates were identified as Lactobacillus sakei, Enterococcus faecium, Lactobacillus helveticus, Leuconstoc lactis, Enterococcus feacalis, Lactobacillus brevis and Weissella hellenica, whereas 15 yeast isolates were identified as Kluyveromyces marxianus, Kazahstan uiosporus, and Candida ethanolica. Results showed also that Lactobacillus and Enterococcus as well as Kluyveromyces were the predominant genera, with the most frequently isolated species being Lactobacillus sakei and Enterococcus faecium as well as Kluyveromyces maxius, respectively. This is the first report on the characterization of dominant microflora of shubat in China.

Characterization of exopolysaccharide (EPS) produced by Weissella hellenica SKkimchi3 isolated from kimchi

Weissella hellenica SKkimchi3 produces the higher exopolysaccharide (EPS) on sucrose than lactose, glucose, and fructose at pH 5 and 20 degrees C. Sucrose was exclusively used to cultivate SKkimchi3 in all experiments base on the EPS production tests. The molecular mass of EPS, as determined by gel permeation chroma-tography, was 203,000. (1)H and (13)C NMR analysis indicated that the identity of EPS may be a glucan. When EPS, starch, and cellulose was treated with a-amylase, glucoamylase, glucosidase, and cellulase, glucose was produced from starch and cellulose but was not produced from EPS. Based on HPLC analysis, elemental analysis, (1)H and (13)C NMR analysis, and enzymatic hydrolysis tests, EPS was estimated to be a glucan. EPS suspension was not precipitated even by centrifugation at 10,000xg for 60 min, and EPS made the fermented milk and bacterial culture viscous.

Leuconostoc carnosum Associated with Spoilage of Refrigerated Whole Cooked Hams in Greece

A polyphasic taxonomic approach was used to identify a major atypical group of gas-forming, arginine-negative lactic acid bacteria associated with spoilage of whole (nonsliced) refrigerated (4°C) cooked hams produced in two Greek industrial meat plants. Biochemical characterization revealed that the ham isolates shared their phenotypic properties with Leuconostoc carnosum, Weissella viridescens, and Weissella hellenica. However, gas chromatographic analysis of cellular fatty acids clearly differentiated the ham isolates from the Weissella spp. None of the isolates contained eicosenoic acid (n-C20:1), which is typically synthesized by W. viridescens, but all strains contained high amounts of C19cycl acid, which is absent in W. hellenica and has been found in trace amounts in W. viridescens. All strains had similar cellular fatty acid profiles, which were qualitatively similar to those of the cellular fatty acids of L. carnosum. In addition to the phenotypic and chemotaxonomic tests, three representative isolates were studied using a lactic acid bacteria database, which employs 16S and 23S HindIII restriction fragment length polymorphism patterns as operational taxonomic units in a numerical analysis. The isolate patterns were identical to those of the L. carnosum type strain, NCFB 2776T. Based on the polyphasic taxonomic approach, the dominating lactic acid bacteria group was identified as L. carnosum.

Usefulness of Rapid GC Analysis of Cellular Fatty Acids for Distinguishing Weissella viridescens, Weissella paramesenteroides, Weissella hellenica and some Non-identifiable, Arginine-negative Weissella Strains of Meat Origin

In an attempt to differentiate between Weissella viridescens, W. paramesenteroides, W. hellenica and some atypical arginine-negative Weissella isolates from meats, their cellular fatty acid composition was determined by a rapid GC method. Results showed that W. viridescens synthesized eicosenoic (n-C20:1) acid, while the other two species did not. Meanwhile, unlike W. paramesenteroides, W. hellenica lacked cyclopropane fatty acids with 19 carbon atoms, i.e. dihydrosterculic or lactobacillic acid. Weissella viridescens contained zero to low amounts (< 1%) of C19 cycl. Original meat isolates identified as W. viridescens or W. hellenica shared similar fatty acid profiles with the respective type strains, whereas the "wild" atypical Weissella isolates resembled more with W. paramesenteroides, and all together with Leuconostoc mesenteroides subsp. mesenteroides. Interesting variations were noted in the total C19 cycl contents among unidentified Weissella, being generally consistent with their grouping based on the type of lactate they formed and the whole-cell protein profile similarity they shared.

Specific probiotic characterization of Weissella hellenica DS-12 isolated from flounder intestine.

A total of 199 microorganisms were isolated from the intestinal contents of flounder (Paralichthys olivaceus) in a fish farm in Seoul, Korea. Among these strains, DS-12 was selected as a candidate for flounder probiotics because of its excellent exhibition of antimicrobial activity against fish pathogens such as edwardsiella, pasteurella, aeromonas, and vibrio, and initiate growth in 10% NaCl, 10% bile, and in broth at pH 3 for 90 min. This strain was Gram-positive, and catalase-negative coccoid rods that produced gas from glucose and formed more than 90% of lactate as the D(-) isomer. This organism is positioned at a cluster in the genus Weissella on the phylogenetic tree based on 16S rRNA sequences, which were assigned to Weissella hellenica on the basis of DNA-DNA relatedness. However, the type strain of W. hellenica JCM 10103(T) had no antibacterial activity against the fish pathogenic bacteria and was found to be quite different from the DS-12 strain in some sugar fermentation patterns of alpha-methyl-D-glucoside, esculine, cellobiose, melibiose, D-raffinose, and D-turanose, being especially unable to grow at 15 and 35 degrees C in 7% NaCl and 10% bile. The results obtained in the present study demonstrated that the type strain of W. hellenica had no probiotic characteristics, but the strain DS-12 could be used as a specific probiotic for flounder.

Atypical Leuconostoc-like Weissella Strains isolated from Meat, Sharing Low Phenotypic Relatedness with the so far Recognized Arginine-negative Weissella spp. as Revealed by SDS-PAGE of Whole Cell Proteins

Summary The levels of phenotypic relatedness among 34 atypical, arginine-negative Weissella strains isolated from naturally fermented Greek dry salami and the species Weissella paramesenteroides (type strain), Weissella hellenica (five strains including type strain), Weissella viridescens (four strains and a reference strain) and Leuconostoc mesenteroides subsp. mesenteroides (one strain) were determined by numerical analysis of whole cell protein profiles. W. paramesenteroides was phenotypically more closely related to Lc. mesenteroides rather than to W. hellenica and W. viridescens. Clearly separated from these four species, atypical Weissella strains formed three distinct clusters, which were also of low phenotypic similarity to each other. Two of the clusters were tight and comprised strains capable of producing solely D-lactate. The third cluster was very diverse as consisted of four subgroups and an “intruder” strain. Most strains of this cluster formed D(L)-lactate. Based on the SDS-PAGE findings, evidence was provided that atypical sausage isolates may represent new, unidentified Weissella taxons of meat origin.

Taxonomic studies on some leuconostoc‐like organisms from fermented sausages: description of a new genus Weissella for the Leuconostoc paramesenteroides group of species

Taxonomic studies were performed on some unknown Leuconostoc-like organisms from fermented Greek sausage. Comparative 16S rRNA sequence analysis showed the unidentified organisms represent a new line within the Leuconostoc paramesenteroides group of species. On the basis of the results of this and earlier phylogenetic investigations, it is proposed that Leuconostoc paramesenteroides and related species be reclassified in a new genus Weissella. In addition a new species, Weissella hellenica, is proposed for the isolates from fermented sausage.