Partial characterization of bacteriocins produced by human Lactococcus lactis and Pediococccus acidilactici isolates

AIMS: The aim of this study was to isolate bacteriocin-producing lactic acid bacteria (LAB) from human intestine. METHODS AND RESULTS: A total of 111 LAB were isolated from human adult stool and screened for their bacteriocin production. Neutralized cell-free supernatants from Lactococcus lactis subsp. lactis MM19 and Pediococcus acidilactici MM33 showed antimicrobial activity. The antimicrobials in the supernatant from a culture of L. lactis inhibited Enterococcus faecium, various species of Lactobacillus and Staphylococcus aureus; while those in the supernatant from a culture of P. acidilactici inhibited Enterococcus spp., some lactobacilli and various serotypes of Listeria monocytogenes. The antimicrobial metabolites were heat-stable and were active over a pH range of 2-10. The antimicrobial activities of the supernatants of both bacteria were inhibited by many proteases but not by catalase. The plate overlay assay allowed an approximation of size between 3.5 and 6 kDa for both antimicrobial substances. CONCLUSIONS: As the antagonistic factor(s) produced by L. lactis MM19 and P. acidilactici MM33 were sensitive to proteolytic enzymes, it could be hypothesized that bacteriocins were involved in the inhibitory activities. Inhibition spectrum and biochemical analysis showed that these bacteria produced two distinct bacteriocins. SIGNIFICANCE AND IMPACT OF THE STUDY: We are the first to isolate bacteriocin-producing strains of Pediococcus and Lactococcus from human intestine. These strains might be useful for control of enteric pathogens.     

Use of hydrolysates from Atlantic cod (Gadus morhua L.) viscera as a complex nitrogen source for lactic acid bacteria

Hydrolysates of cod viscera were tested as an alternative to commonly used complex nitrogen sources (peptones and/or extracts) for the type strains of the lactic acid bacteria Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus sakei and Pediococcus pentosaceus. Comparative studies with MRS-like media containing different nitrogen sources showed that all the fish hydrolysates performed equally well or better than commercial extracts/peptones for all selected lactic acid bacteria.     

Characterization and antimicrobial spectrum of bacteriocins produced by lactic acid bacteria isolated from traditional Bulgarian dairy products

Aims:  To isolate bacteriocin-producing lactic acid bacteria (LAB) with high wide spectrum antibacterial activity and to characterize their inhibitory peptides.
Method and Results:  Seven LAB strains [ Lactobacillus casei ssp. rhamnosus (PC5), Lactobacillus delbrueckii ssp. bulgaricus (BB18), Lactococcus lactis ssp. lactis (BCM5, BK15), Enterococcus faecium (MH3), Lactobacillus plantarum (BR12), Lactobacillus casei ssp. casei (BCZ2)], isolated from authentic Bulgarian dairy products were capable of producing bacteriocins, inhibiting the widest range of pathogenic bacteria. The bacteriocins were resistant to heating at 121°C for 15 min, stable at pH 2–10, sensitive to protease, insensitive to α-amylase and lipase. Two of bacteriocins produced by Lact. bulgaricus BB18 (bulgaricin BB18) and E. faecium MH3 (enterocin MH3) were purified and the molecular masses were determined. The N -terminal amino acid sequence of bulgaricin BB18 did not show strong homology to other known bacteriocins.
Conclusions:  Lactobacillus bulgaricus BB18 and E. faecium MH3 produce two novel bacteriocins highly similar to the pediocin-like nonlantibiotics.
Significance and Impact of the Study:  The two bacteriocins are potential antimicrobial agents and, in conjunction with their producers, may have use in applications to contribute a positive effect on the balance of intestinal microflora. Furthermore, bulgaricin BB18 strongly inhibits Helicobacter pylori .     

Screening for proteolytically active lactic acid bacteria and bioactivity of peptide hydrolysates obtained with selected strains

Applied Microbiology and Biotechnology - In a screening for proteolytically active lactic acid bacteria, three strains, Lactobacillus delbrueckii ssp. lactis 92202, Lactobacillus helveticus 92201,...     

Biodiversity of lactic acid bacteria in Moroccan soft white cheese (Jben)

The bacterial diversity occurring in traditional Moroccan soft white cheese, produced in eight different regions in Morocco, was studied. A total of 164 lactic acid bacteria were isolated, purified and identified by whole-cell protein fingerprinting and rep-PCR genomic fingerprinting. The majority of the strains belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Enterococcus. Sixteen species were identified: Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, Lactobacillus brevis, Lactobacillus buchneri, Lactococcus lactis, Lactococcus garvieae, Lactococcus raffinolactis, Leuconostoc pseudomesenteroides, Leuconostoc mesenteroides, Leuconostoc citreum, Eterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus saccharominimus and Streptococcus sp.     

Preliminary characterization of lactic acid bacteria isolated from Zlatar cheese

AIMS: Isolation, characterization and identification of lactic acid bacteria (LAB) from artisanal Zlatar cheese during the ripening process and selection of strains with good technological characteristics. METHODS AND RESULTS: Characterization of LAB was performed based on morphological, physiological and biochemical assays, as well as, by determining proteolytic activity and plasmid profile. rep-polymerase chain reaction (PCR) analysis and 16S rDNA sequencing were used for the identification of LAB. PCR analysis was performed with specific primers for detection of the gene encoding nisin production. Strains Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactobacillus brevis, Lactococcus lactis subsp. lactis, Enterococcus faecium and Enterococcus faecalis were the main groups present in the Zlatar cheese during ripening. CONCLUSIONS: Temporal changes in the species were observed during the Zlatar cheese ripening. Mesophilic lactobacilli are predominant microflora in Zlatar cheese. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study we determined that Zlatar cheese up to 30 days old could be used as a source of strains for the preparation of potential starter cultures in the process of industrial cheese production. As the Serbian food market is adjusting to European Union regulations, the standardization of Zlatar cheese production by using starter culture(s) based on autochtonous well-characterized LAB will enable the industrial production of this popular cheese in the future.     

Spread and variability of the integrase gene in Lactobacillus delbrueckii ssp. lactis strains and phages isolated from whey starter cultures

AIMS: To determine the presence, diffusion and variability of the integrase (int) gene in Lactobacillus delbrueckii ssp. lactis isolated from natural whey starters used for the production of Italian hard cheeses. METHODS AND RESULTS: A PCR-based protocol aimed to amplify an internal fragment of the int gene was optimized taking into account phage genome sequences available from public databases. Thirty-seven of the 39 strains tested showed the presence of the putative int gene. Southern blot hybridization experiments confirmed data obtained by PCR. The presence of the putative int gene was observed also in 20 of 23 Lact. delbrueckii ssp. lactis lytic phages isolated from the same starter cultures used to isolate strains. Phylogenetic analysis of partial int gene revealed a high similarity both within and between strain- and phage-derived sequences. Sixty per cent of the int-positive strains resulted inducible with mitomycin C, and two of them released active phage particles. CONCLUSIONS: Our preliminary findings seem to suggest that an important number of Lact. delbrueckii ssp. lactis strains associated with the whey starters are lysogenic. SIGNIFICANCE AND IMPACT OF THE STUDY: Further contribution to obtain a clearer picture of the complex relationship between thermophilic lactic acid bacteria phage and host in whey starters for Italian, hard-cooked cheeses.     

Antimicrobial susceptibility of lactic acid bacteria isolated from a cheese environment

In the production of the Spanish traditional blue-veined Cabrales cheese, lactic acid bacteria strains free of antibiotic resistance that have a transferrable capacity are necessary as components of a specific starter. To select for these bacteria, the minimum inhibitory concentration (MIC) of 12 antibiotics and 2 mixtures (containing beta-lactamase inhibitor and penicillin) were determined by microbroth and agar dilution techniques in 146 strains belonging to the genera Lactococcus, Enterococcus, Lactobacillus, and Leuconostoc. The antibiotic-resistance profiles of Lactococcus and Enterococcus species were different from those of Lactobacillus and Leuconostoc, but clear genus- or species-associated patterns were not observed. Cefoxitin and metronidazole were not effective against bacteria of these genera. The MICs of beta-lactam antibiotics for lactobacilli and leuconostoc isolates were higher than those for lactococci and enterococci, but no strain was clinically resistant. All lactobacilli and leuconostoc isolates were resistant to high levels of vancomycin, a type of resistance not seen among the tested members of the genera Lactococcus and Enterococcus. The majority of the observed resistance appeared to be either intrinsic or nonspecific, although some strains of Lactococcus lactis, Enterococcus spp., and Lactobacillus spp. were resistant to antibiotics, such as chloramphenicol, erythromycin, clindamycin, or tetracycline.     

Characterization and determination of origin of lactic acid bacteria from a sorghum-based fermented weaning food by analysis of soluble proteins and amplified fragment length polymorphism fingerprinting

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known, and these organisms have been characterized extensively by using different techniques. In this study, 180 lactic acid bacterial strains isolated from sorghum powder (44 strains) and from corresponding fermented (93 strains) and cooked fermented (43 strains) porridge samples that were prepared in 15 households were characterized by using biochemical and physiological methods, as well as by analyzing the electrophoretic profiles of total soluble proteins. A total of 58 of the 180 strains were Lactobacillus plantarum strains, 47 were Leuconostoc mesenteroides strains, 25 were Lactobacillus sake-Lactobacillus curvatus strains, 17 were Pediococcus pentosaceus strains, 13 were Pediococcus acidilactici strains, and 7 were Lactococcus lactis strains. L. plantarum and L. mesenteroides strains were the dominant strains during the fermentation process and were recovered from 87 and 73% of the households, respectively. The potential origins of these groups of lactic acid bacteria were assessed by amplified fragment length polymorphism fingerprint analysis.     

In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acid bacteria during sourdough fermentation

AIMS: To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation. METHODS AND RESULTS: A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the non-interference with the growth of the starter strain Lact. sanfranciscensis CB1. CONCLUSIONS: In situ active bacteriocins influence the microbial consortium of sourdough LAB and can "support" the dominance of insensitive strains during sourdough fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The in situ bacteriocinogenic activity of selected lactococci enables the persistence of insensitive Lact. sanfranciscensis strains, useful to confer good characteristics to the dough, at a higher cell concentration with respect to other LAB of the same ecosystem.     

Dominant lactic acid bacteria and their technological properties isolated from the Himalayan ethnic fermented milk products

Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.     

内蒙古呼伦贝尔地区传统发酵乳中乳酸菌的多样性分析

【目的】对内蒙古呼伦贝尔地区传统发酵乳制品中乳酸菌资源的生物多样性进行研究。【方法】采用纯培养和16S rRNA基因序列分析法对内蒙古呼伦贝尔地区传统发酵乳中的乳酸菌进行多样性分析。【结果】从8份传统发酵乳制品(6份酸牛奶和2份酸马奶)样品中分离到24株乳酸菌,通过16S rRNA基因序列分析和系统进化关系分析将24株乳酸菌鉴定为2株Lactobacillus kefiranofaciens、2株Lactobacillus kefiri、5株Lactobacillus paracasei、3株Lactobacillus plantarum、1株Lactobacillus rhamnosus、6株Lactococcus lactis subsp.lactis、2株Leuconostoc mesenteroides subsp.dextranicum、2株Streptococcus thermophilus和1株Enterococcus faecium。【结论】Lactococcus lactis subsp.lactis为内蒙古呼伦贝尔地区传统发酵乳制品的优势菌种,占总分离株的25%,其次为Lactobacillus paracasei,占总分离株的20.83%。     

Functional compounds in fermented buckwheat sprouts

Fermented buckwheat sprouts (FBS) are used as multifunctional foods. Their production process includes fermentation with lactic acid bacteria. The major strains were found to include Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus pentosus, Lactococcus lactis subsp. lactis, and Pediococcus pentosaceus in an investigation of the lactic acid bacteria. We searched for the functional components, and nicotianamine (NA) and 2″-hydroxynicotianamine (HNA) were identified as angiotensin I-converting enzyme (ACE) inhibitors. NA and HNA increased during fermentation. Indole-3-ethanol was identified as an antioxidant (a SOD active substance), and may have been generated from tryptophan during fermentation because it was not contained in green buckwheat juice. A safety test demonstrated that FBS contained were safe functional food components, showing negative results in buckwheat allergy tests. Any buckwheat allergy substances might have been degraded during the fermentation process.     

Usefulness of length heterogeneity-PCR for monitoring lactic acid bacteria succession during maize ensiling

The use of length-heterogeneity PCR was explored to monitor lactic acid bacteria succession during ensiling of maize. Bacterial diversity was studied during the fermentation of 30-day-old maize in optimal and spoilage-simulating conditions. A length heterogeneity PCR profile database of lactic acid bacteria isolated from the silage and identified by 16S rRNA gene sequencing was established. Although interoperonic 16S rRNA gene length polymorphisms were detected in some isolates, strain analysis showed that most of the lactic acid bacteria species thriving in silage could be discriminated by this method. The length heterogeneity PCR profiles of bacterial communities during maize fermentation were compared with those on a database. Under optimal fermentation conditions all the ecological indices of bacterial diversity, richness and evenness, deduced from community profiles, increased until day thirteen of fermentation and then decreased to the initial values. Pediococcus and Weissella dominated, especially in the first days of fermentation. Lactococcus lactis ssp. lactis and Lactobacillus brevis were mainly found after six days of fermentation. A peak corresponding to Lactobacillus plantarum was present in all the fermentation phases, but was only a minor fraction of the population. Unsuitable fermentation conditions and withered maize leaves in the presence of oxygen and water excess caused an enrichment of Enterococcus sp. and Enterobacter sp.     

Lactic acid bacteria associated with wine grapes from several Australian vineyards

AIMS: The detection and isolation of lactic acid bacteria by enrichment methods from wine grapes cultivated in vineyards located in New South Wales, Australia. METHODS AND RESULTS: Enrichment cultures in de Man, Rogosa and Sharpe (MRS) broth, MRS + ethanol (5%), MRS broth supplemented with 15% (v/v) tomato juice (MRST), pH 5.5 and 3.5 and autoenrichment in grape juice homogenate were used to detect lactic acid bacteria on wine grapes. Bacteria were isolated from enrichment cultures by plating onto MRS and MRST agar and identified by 16S rDNA sequence analysis and phenotypical methods. A molecular method, PCR-denaturing gradient gel electrophoresis (DGGE) was also used to examine the bacteria that developed in enrichment cultures. Species of Lactobacillus, Enterococcus, Lactococcus and Weissella were detected in enrichments by plating and PCR-DGGE. Other bacteria (Sporolactobacillus, Asaia, Bacillus ssp.) were also found in some enrichment cultures. The principal malolactic bacterium, Oenococcus oeni, was not isolated. CONCLUSIONS: The incidence and populations of lactic acid bacteria on wine grapes were very low. Damaged grape berries showed a greater presence of these bacteria than undamaged berries. The diversity of bacterial species isolated from the grapes was greater than those previously reported and represented both lactic acid bacteria and nonlactic acid bacteria. Some of these bacteria (i.e. Lactobacillus lindneri, Lactobacillus kunkeei) could be detrimental to wine production. Oenococcus oeni was not found on grapes, but its recovery could be obscured by overgrowth from other species. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactic acid bacteria are significant in wine production because they conduct the malolactic fermentation and cause stuck or sluggish alcoholic fermentation and wine spoilage. This study investigates wine grapes as a potential source of these bacteria.     

Development and Characterization of Lactose-Positive Pediococcus Species for Milk Fermentation

Bacteriophages against Streptococcus thermophilus are a growing problem in the Italian cheese industry. One possible control method involves replacing S. thermophilus in mozzarella starter blends with lactic acid bacteria from a different genus or species. In this study, we evaluated lactose-positive pediococci for this application. Because we could not identify any commercially available pediococci with fast acid-producing ability in milk, we transformed Pediococcus pentosaceus ATCC 25744, P. pentosaceus ATCC 25745, and Pediococcus acidilactici ATCC 12697 by electroporation with pPN-1, a 35-kb Lactococcus lactis lactose plasmid. Transformants of P. pentosaceus ATCC 25745 and P. acidilactici ATCC 12697 were then used to examine lactose-positive pediococci for properties related to milk fermentation. Both transformants rapidly produced acid and efficiently retained pPN-1 in lactose broth, and neither bacterium was attacked by bacteriophages in whey collected from commercial cheese facilities. Paired starter combinations of Pediococcus spp. and Lactobacillus helveticus LH100 exhibited synergistic pH reduction in milk, and small-scale cheese trials showed that these cultures could be used to manufacture part-skim mozzarella cheese. Results demonstrate that lactose-positive pediococci have potential as replacement cocci for S. thermophilus in Italian cheese starter blends and may facilitate development of new strain rotation schemes to combat S. thermophilus bacteriophage problems in mozzarella cheese plants.     

Characterization of bacteriocin-like inhibitory substances (BLIS) from sourdough lactic acid bacteria and evaluation of their in vitro and in situ activity

AIMS: To identify and characterize bacteriocion-producing lactic acid bacteria (LAB) in sourdoughs and to compare in vitro and in situ bacteriocin activity of sourdough- and nonsourdough LAB. METHODS AND RESULTS: Production of antimicrobial compounds by 437 Lactobacillus strains isolated from 70 sourdoughs was investigated. Five strains (Lactobacillus pentosus 2MF8 and 8CF, Lb. plantarum 4DE and 3DM and Lactobacillus spp. CS1) were found to produce distinct bacteriocin-like inhibitory substances (BLIS). BLIS-producing Lactococcus lactis isolated from raw barley showed a wider inhibitory spectrum than sourdough LAB, but they did not inhibit all strains of the key sourdough bacterium Lb. sanfranciscensis. Antimicrobial production by Lb. pentosus 2MF8 and Lc. lactis M30 was also demonstrated in situ. CONCLUSIONS: BLIS production by sourdough LAB appears to occur at a low frequency, showing limited inhibitory spectrum when compared with BLIS-producing Lc. lactis. Nevertheless, they are active BLIS producers under sourdough and bread-making conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The activity of BLIS has been demonstrated in situ. It may influence the complex sourdough microflora and support the implantation and stability of selected insensitive bacteria, such as Lb. sanfranciscensis, useful to confer good characteristics to the dough.     

DNA-DNA homology, physiological characteristics and distribution of lactic acid bacteria isolated from maize silage

Lactic acid bacteria represent a dynamic bacterial group in maize silages. their establishment, variations and characterization have been studied by investigating 22 samples taken at different times during the ensilage process. After a preliminary screening based on physiological characteristics, 100 of 229 strains isolated were chosen for further taxonomic investigation. Twenty-nine strains of homo-fermentative lactobacilli were identified as Lactobacillus plantarum, L. casei and L. coryniformis subsp. coryniformis ; 24 heterofermentative strains were allotted to the species L. buchneri, L. brevis, L. fermentum and Leuconostoc paramesenteroides ; 22 coccal strains were assigned to Pediococcus pentosaceus and P. acidilactici and 25 coccal strains were identified as Enterococcus faecium, Streptococcus lactis and Strep. bovis. A few strains remained unidentified.     

Autolytic activity and pediocin-induced lysis in Pediococcus acidilactici and Pediococcus pentosaceus strains

AIMS: To evaluate the autolytic phenotype of Pediococcus acidilactici and P. pentosaceus, the peptidoglycan hydrolases content and the effect of pediocin AcH/PA-1 and autolysins on cell lysis. METHODS AND RESULTS: The autolytic phenotype of Pediococcus strains was evaluated under starvation conditions in potassium phosphate buffer. The strains tested showed an extent of autolysis ranging between 40 and 90% after 48 h of starvation at 37 degrees C. Peptidoglycan hydrolase content was evaluated by renaturing sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) using cells of Micrococcus lysodeikticus as a target for the enzymatic activity and a major activity band migrating at about 116 kDa was detected. Additional secondary lytic bands migrating in a range of molecular weight between 45 and 110 kDa were also detected. The lytic activity, evaluated in the presence of different chemicals, was retained in 15 mM CaCl2 and in a range of pH between 5 and 9.5 but was strongly reduced in presence of 8% NaCl and in the presence of protease inhibitors. The substrate specificity of peptidoglycan hydrolases of Pediococcus strains was evaluated in renaturing SDS-PAGE incorporating cells of different bacterial species. Lytic activity was detected against cells of Lactococcus lactis subsp. lactis, L. delbrueckii subsp. bulgaricus, Lactobacillus helveticus and Listeria monocytogenes. The interaction between pediocin AcH/PA-1 and autolysis was evaluated and a relevant effect of bacteriocin in cell-induced lysis was observed. CONCLUSIONS: The autolytic phenotype is widely distributed among P. acidilactici and P. pentosaceus and the rate of autolysis is high in the majority of the analysed strains. Several autolytic bands, detected by renaturing SDS-PAGE, retained their activity against several lactic acid bacteria and L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: The characterization of the autolytic phenotype of Pediococcus acidilactici and P. pentosaceus strains should expand the knowledge of their role in fermentation processes where these species occur as primary or secondary bacterial population.     

Phylogenetic diversity of lactic acid bacteria associated with paddy rice silage as determined by 16S ribosomal DNA analysis

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.