Probiotic and milk technological properties of Lactobacillus brevis

Probiotic properties of lactobacilli species isolated from children's feces

In the present research, the 20 lactobacilli isolated from children feces aged 4-15 years old were investigated for their capabilities to survive at pH 2.0, 2.5, 3.0 and in the presence of 0.25, 0.50 and 0.75% bile salts, their effect on the growth of pathogens, in addition to their sensitivity against 13 selected antibiotics. All the lactobacilli strains were able to survive in low pH and bile salt conditions at pH 2.0 and 0.25% bile salt for 2 h. Moreover, all lactobacilli strains exhibited inhibitory activity against Escherichia coli ATCC 11229, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213. In addition, all lactobacilli strains indicated resistance to teicoplanin, vancomycin, and bacitracin. The amount of exopolysaccharide (EPS) produced by the strains was 70 and 290 mg/L. The capabilities to autoaggregation and coaggregate with E. coli ATCC 11229 of the strains were also evaluated. High EPS-producing strains indicated significant autoaggregation and coaggregation capability with test bacteria (p < 0.01). The maximum cholesterol removal (76.5%) was observed by strain Lactobacillus pentosus T3, producing a high amount of exopolysaccharide, in 0.3%oxgall concentration (p < 0.05). Our results demonstrate that the capability to EPS production, acid-bile tolerance, antimicrobial activity, antibiotic resistance, aggregation and cholesterol removal of lactobacilli could be utilized for preliminary screening in order to identify potentially probiotic bacteria suitable for human.

The gut microbiome: the role of a virtual organ in the endocrinology of the host

The human microbiome contains a vast array of microbes and genes that show greater complexity than the host's own karyome; the functions of many of these microbes are beneficial and show co-evolution with the host, while others are detrimental. The microbiota that colonises the gut is now being considered as a virtual organ or emergent system, with properties that need to be integrated into host biology and physiology. Unlike other organs, the functions that the gut microbiota plays in the host are as yet not fully understood and can be quite easily disrupted by antibiotics, diet or surgery. In this review, we look at some of the best-characterised functions that only the gut microbiota plays and how it interacts with the host's endocrine system and we try to make it clear that the 21st-century biology cannot afford to ignore this facet of biology, if it wants to fully understand what makes us human.

Screening of Lactobacillus isolated from pork sausages for potential probiotic use and evaluation of the microbiological safety of fermented products

The aim of this study was to select strains of Lactobacillus isolated from pork sausage for use as probiotics. Lactobacillus isolates were evaluated in tests based on probiotic characteristics and microbiological safety. The UFLA SAU 14, 52, and 91 isolates were differentiated by coaggregation with Listeria monocytogenes, production of lactic acid, and survival at pH 2. UFLA SAU 172 and 187 isolates had high levels of coaggregation with Salmonella Typhi and Escherichia coli, tolerance to pancreatic fluid, and adhesion to chloroform. UFLA SAU 20 and 34 isolates were characterized by exopolysaccharide production, autoaggregation, and resistance to simulated intestinal fluid. UFLA SAU 185, 238, and 258 isolates exhibited resistance to bile and adhesion to xylene. A cocktail of these 10 Lactobacillus isolates with potential probiotic properties was inoculated into pork sausage and inhibited the growth of L. monocytogenes.

Genomic analysis by deep sequencing of the probiotic Lactobacillus brevis KB290 harboring nine plasmids reveals genomic stability

We determined the complete genome sequence of Lactobacillus brevis KB290, a probiotic lactic acid bacterium isolated from a traditional Japanese fermented vegetable. The genome contained a 2,395,134-bp chromosome that housed 2,391 protein-coding genes and nine plasmids that together accounted for 191 protein-coding genes. KB290 contained no virulence factor genes, and several genes related to presumptive cell wall-associated polysaccharide biosynthesis and the stress response were present in L. brevis KB290 but not in the closely related L. brevis ATCC 367. Plasmid-curing experiments revealed that the presence of plasmid pKB290-1 was essential for the strain's gastrointestinal tract tolerance and tendency to aggregate. Using next-generation deep sequencing of current and 18-year-old stock strains to detect low frequency variants, we evaluated genome stability. Deep sequencing of four periodic KB290 culture stocks with more than 1,000-fold coverage revealed 3 mutation sites and 37 minority variation sites, indicating long-term stability and providing a useful method for assessing the stability of industrial bacteria at the nucleotide level.

Effects of Enteric-coated Lactoferrin Tablets Containing Lactobacillus brevis subsp. coagulans on Fecal Properties, Defecation Frequency and Intestinal Microbiota of Japanese Women with a Tendency for Constipation: a Randomized Placebo-controlled Crossover Study

The effects of oral administration of enteric-coated tablets containing lactoferrin (LF; 100 mg/tablet) and heat-killed Lactobacillus brevis subsp. coagulans FREM BP-4693 (LB; 6×10⁹ bacteria/tablet) on fecal properties were examined in 32 Japanese women (20–60 years of age) with a tendency for constipation (defecation frequency at equal to or less than 10 times/2 weeks) by a double-blind placebo-controlled crossover design. A significant increase in defecation days per week was obserbed in the subjects who ingested the tablets containing LF and LB compared with the placebo group. The number of bifidobacteria in feces also significantly increased compared with the placebo group. In an in vitro study, LF and tryptic hydrolysate of LF, but not peptic hydrolysate of LF, upregulated the growth of Bifidobacterium longum ATCC15707 when added to the culture. These results demonstrate the capability of the enteric-coated tablets containing LF and LB in improving intestinal function and suggest that they have a growth promoting function for bifidobacteria.

Screening for probiotic properties of strains isolated from feces of various human groups

The present study searched for potential probiotic strains from various human fecal samples. A total of 67 aerobic and 38 anaerobic strains were isolated from 5 different categories of human feces. Systematic procedures were used to evaluate the probiotic properties of the isolated strains. These showed about 75-97% survivability in acidic and bile salt environments. Adhesion to intestinal cell line Caco-2 was also high. The isolates exhibited hydrophobic properties in hexadecane. The culture supernatants of these strains showed antagonistic effects against pathogens. The isolates were resistant to a simulated gastrointestinal environment in vitro. Of the 4 best isolates, MAbB4 (Staphylococcus succinus) and FIdM3 (Enterococcus fecium), were promising candidates for a potential probiotic. S. succinus was found to be a probiotic strain, which is the second such species reported to date in this particular genus. A substantial zone of inhibition was found against Salmonella spp., which adds further support to the suggestion that the probiotic strain could help prevent intestinal infection. This study suggested that the human flora itself is a potential source of probiotics.

Modification of the technical properties of Lactobacillus johnsonii NCC 533 by supplementing the growth medium with unsaturated fatty acids

The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 μg/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 μg/ml). Following acid exposure, significantly higher (P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical properties underlying probiotic survivability can be affected by nutrient composition of the growth medium.

Probiotic properties of Lactobacillus strains isolated from the feces of breast-fed infants and Taiwanese pickled cabbage

This study assessed potential probiotic Lactobacillus strains isolated from the feces of breast-fed infants and from Taiwanese pickled cabbage for their possible use in probiotic fermented foods by evaluating their (i) in vitro adhesive ability, resistance to biotic stress, resistance to pathogenic bacteria, and production of β-galactosidase; (ii) milk technological properties; and (iii) in vivo adhesive ability, intestinal survival and microbial changes during and after treatment. Five Lactobacillus isolates identified as Lactobacillus reuteri F03, Lactobacillus paracasei F08, Lactobacillus rhamnosus F14, Lactobacillus plantarum C06, and Lactobacillus acidophilus C11 that showed resistance to gastric juice and bile salts were selected for further evaluation of their probiotic properties. All the strains demonstrated the ability to adhere to Caco-2 cells, particularly, strain L. plantarum C06 and L. reuteri F03 showed satisfactory abilities, which were similar to that of the reference strain L. rhamnosus GG. The strains L. paracasei F08 and L. acidophilus C11 had the highest β-galactosidase activity. Most of the strains were resistant to aminoglycosides and vancomycin but sensitive to ampicillin, erythromycin, and penicillin. All the 5 strains elicited antibacterial activity against both Gram-positive (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) and -negative (Escherichia coli and Salmonella enterica) pathogens. Moreover, the strains L. reuteri F03, L. paracasei F08, and L. plantarum C06 could grow rapidly in milk without nutrient supplementation and reached 10⁸ cfu/mL after 24 h of fermentation at 37 °C. The viable cell counts of the 3 strains remained above 10⁷ cfu/mL after 21 d of storage at 4 °C. In the animal feeding trial, the number of intestinal lactobacilli increased significantly after administration of milk fermented with the 3 strains, and the counts of fecal coliforms and Clostridium perfringens were markedly reduced. Lactobacillus strains could also survive in the ileal intestinal tissue of the treated rats. Technologically interesting Lactobacillus isolates may be used in the future as probiotic starter cultures for manufacturing novel fermented foods.

Hypocholesterolaemic effect of dietary inclusion of two putative probiotic bile salt hydrolase-producing Lactobacillus plantarum strains in Sprague-Dawley rats

The purpose of the present study was to evaluate the anti-hypercholesterolaemic effects of two putative probiotic bile salt hydrolase (Bsh)-producing Lactobacillus plantarum strains, i.e. Lp91 and Lp21, in rats. L. plantarum Lp91 exhibited excellent tolerance to low pH and high bile salt concentrations as well as showed potential Bsh activity, cholesterol assimilation and cholesterol co-precipitation ability along with L. plantarum Lp21 and NCDO82 strains. Furthermore, the potential effect of L. plantarum Lp91 on plasma cholesterol level was evaluated in Sprague-Dawley rats. Five treatment groups of rats (n 6) were fed experimental diets: normal diet, hypercholesterolaemic diet (HD), HD plus L. plantarum Lp91 (HD91) at ≥ 1·0 × 108 colony-forming units (cfu)/g, HD plus microencapsulated L. plantarum Lp91 (HDCap91) at ≥ 1·0 × 108 cfu/g and HD plus L. plantarum Lp21 (HD21) at ≥ 1·0 × 108 cfu/g for 3 weeks. Feed intake and feed efficiency differed significantly among the five groups. After 21 d of dietary treatment, comparative analysis revealed 23·26, 15·71 and 15·01 % reduction in total cholesterol, 21·09, 18·77 and 18·17 % reduction in TAG, 38·13, 23·22 and 21·42 % reduction in LDL-cholesterol, and the corresponding HDL-cholesterol values increased at the rate of 18·94, 10·30 and 7·78 % in treated groups HD91, HDCap91 and HD21, respectively. Faecal excretion of cholic acid and faecal lactobacilli counts were significantly higher in the probiotic treatment groups than in the control groups. In conclusion, these results suggest that the indigenous L. plantarum Lp91 strain has the potential to be explored as a probiotic in the management of hypercholesterolaemia.

Characterization and separate activities of the two promoters of the Lactobacillus brevis S-layer protein gene

Lactobacillus brevis ATCC 8287 possesses a surface (S)-layer protein SlpA, the gene of which is very efficiently expressed. To study the expression signals of the slpA gene, several different reporter plasmids, based on the low-copy-number vector pKTH2121 derived from pGK12, were constructed. In the reporter plasmids, only one of the two consecutive slpA promoters (P1, P2) was placed upstream of the Lactobacillus helveticus proline iminopeptidase (pepI) gene, and defined parts of the sequences upstream of the promoter were deleted. As indicated by reporter enzyme activities, both promoters were efficiently recognized at different growth stages in L. brevis. An upstream region important for the full activity of P1 was identified. The quantification of pepI-specific mRNA in L. brevis and SDS-PAGE indicated that slpA expression is not regulated at the post-transcriptional level and revealed no regulation of slpA promoters under the conditions tested. The high expression levels of both slpA and the reporter gene in L. brevis were found to remain at a high level after the addition of bile or pancreatin in the growth medium or after a change of the carbon source, which is advantageous for the potential use of SlpA as a carrier in live oral vaccines.

Structural characterization of teichoic acids from Lactobacillus brevis

Teichoic acids are a major constituent of the cell wall of Gram-positive bacteria. Structural characterization of lipoteichoic and teichoic acids isolated from Lactobacillus brevis was undertaken using 1D and 2D NMR experiments as well as chemical methodology. Compositional analysis indicated the presence of high amounts of glycerol, glucose, and alanine. In the case of LTA octadecenoic acid was also detected. The basic LTA/WTA structure was identified as 1,3-poly(glycerol phosphate) nonstoichiometrically substituted at C-2 of the glycerol residues with D-Ala or alpha-D-Glc. In the case of LTA a higher amount of Ala could be detected and partial alanylation at position C-6 of the Glc could also be observed.

Safety assessment of Lactobacillus brevis KB290 as a probiotic strain

Lactobacillus brevis KB290 (KB290), a plant-derived probiotic lactic acid bacterium, reportedly improves gut health and stimulates immune function. Here we extensively investigated the geno-, acute, subacute, and subchronic toxicity of KB290 and its bacterial translocation potential. KB290 was non-mutagenic in the bacterial reverse mutation assay by the preincubation method. In the single oral dose toxicity test, KB290 at 10(9) cfu/ml was nontoxic at maximum capacity (20 ml/kg). When 10(8), 10(9), or 10(10) cfu/kg was administered daily to rats by gavage for 2 weeks (subacute assay), we observed no clear treatment-related effect and no evidence of bacterial translocation from the gastrointestinal tract. When it was administered for 13 weeks (subchronic assay), we again observed no clear treatment-related effect and no significant toxicological effect. Based on those results, we consider 10(10) cfu/kg per day, the highest dose tested, to be the no observed adverse effect level (NOAEL). These results suggest that KB290 is safe for human consumption.

Probiotic properties of Lactobacillus rhamnosus and Lactobacillus paracasei isolated from human faeces

BACKGROUND

The possibility of using microbes to maintain health, and to prevent or treat disease is a topic as old as microbiology. The research of novel probiotic strains is important in order to satisfy the increasing request of the market and to obtain functional products in which the probiotic cultures are more active and with better probiotic characteristics than those already present on the market.

AIM OF THE STUDY

In this study, the probiotic potential of Lactobacillus strains isolated from Italian elderly human faeces was investigated.

METHODS

The Lactobacillus strains were identified and examined for resistance to gastric acidity and bile toxicity, adhesion to HT-29 cells, antimicrobial activities, antibiotic susceptibility and plasmid profile. Survival of the strains through human intestine was examined in a 3 months human feeding trial.

RESULTS

Two strains, Lactobacillus rhamnosus IMC 501 and Lactobacillus paracasei IMC 502, tolerated well low pH and bile acids. In antimicrobial activity assays, both strains showed inhibitory properties towards selected potential harmful microorganisms, particularly against Candida albicans. The two selected strains expressed high in vitro adherence to HT-29 cells increasing this characteristic when they are used in combination and they were resistant to vamcomycin, colistin sulphate, gentamicin, oxolinic acid and kanamycin. Moreover, the two strains could be recovered from stools of volunteers after the feeding trials.

CONCLUSIONS

Lactobacillus rhamnosus IMC 501 and L. paracasei IMC 502 present favourable strain-specific properties for their utilisation as probiotics in functional foods and the high adhesion ability of the L. rhamnosus IMC 501 and L. paracasei IMC 502 used in combination, confirmed by both in vitro and in vivo study, indicate that the two bacterial strains could be used as health-promoting bacteria.

Surface location of individual residues of SlpA provides insight into the Lactobacillus brevis S-layer

Bacterial surface layer (S-layer) proteins are excellent candidates for in vivo and in vitro nanobiotechnological applications because of their ability to self-assemble into two-dimensional lattices that form the outermost layer of many Eubacteria and most Archaea species. Despite this potential, knowledge about their molecular architecture is limited. In this study, we investigated SlpA, the S-layer protein of the potentially probiotic bacterium Lactobacillus brevis ATCC 8287 by cysteine-scanning mutagenesis and chemical modification. We generated a series of 46 mutant proteins by replacing single amino acids with cysteine, which is not present in the wild-type protein. Most of the replaced amino acids were located in the self-assembly domain (residues 179 to 435) that likely faces the outer surface of the lattice. As revealed by electron microscopy, all the mutant proteins were able to form self-assembly products identical to that of the wild type, proving that this replacement does not dramatically alter the protein conformation. The surface accessibility of the sulfhydryl groups introduced was studied with two maleimide-containing marker molecules, TMM(PEG)(12) (molecular weight [MW], 2,360) and AlexaFluor488-maleimide (MW = 720), using both monomeric proteins in solution and proteins allowed to self-assemble on cell wall fragments. Using the acquired data and available domain information, we assigned the mutated residues into four groups according to their location in the protein monomer and lattice structure: outer surface of the lattice (9 residues), inner surface of the lattice (9), protein interior (12), and protein-protein interface/pore regions (16). This information is essential, e.g., in the development of therapeutic and other health-related applications of Lactobacillus S-layers.

Identification and characterization of domains responsible for self-assembly and cell wall binding of the surface layer protein of Lactobacillus brevis ATCC 8287

BACKGROUND

Lactobacillus brevis ATCC 8287 is covered by a regular surface (S-) layer consisting of a 435 amino acid protein SlpA. This protein is completely unrelated in sequence to the previously characterized S-layer proteins of Lactobacillus acidophilus group.

RESULTS

In this work, the self-assembly and cell wall binding domains of SlpA were characterized. The C-terminal self-assembly domain encompassed residues 179-435 of mature SlpA, as demonstrated by the ability of N-terminally truncated recombinant SlpA to form a periodic structure indistinguishable from that formed by full length SlpA. Furthermore, a trypsin degradation analysis indicated the existence of a protease resistant C-terminal domain of 214 amino acids. By producing a set of C-terminally truncated recombinant SlpA (rSlpA) proteins the cell wall binding region was mapped to the N-terminal part of SlpA, where the first 145 amino acids of mature SlpA alone were sufficient for binding to isolated cell wall fragments of L. brevis ATCC 8287. The binding of full length rSlpA to the cell walls was not affected by the treatment of the walls with 5% trichloroacetic acid (TCA), indicating that cell wall structures other than teichoic acids are involved, a feature not shared by the Lactobacillus acidophilus group S-layer proteins characterized so far. Conserved carbohydrate binding motifs were identified in the positively charged N-terminal regions of six Lactobacillus brevis S-layer proteins.

CONCLUSION

This study identifies SlpA as a two-domain protein in which the order of the functional domains is reversed compared to other characterized Lactobacillus S-layer proteins, and emphasizes the diversity of potential cell wall receptors despite similar carbohydrate binding sequence motifs in Lactobacillus S-layer proteins.

New convenient defined media for [35S]methionine labelling and proteomic analyses of probiotic lactobacilli

AIMS

To develop experimental conditions for efficient protein radiolabelling and two-dimensional (2D) polyacrylamide gel electrophoresis for investigation of stress proteomes of probiotic Lactobacillus spp.

METHODS AND RESULTS

Three chemically defined media (CDM) optimized from a commercial medium supported rapid growth of the probiotic Lactobacillus rhamnosus E97800, Lactobacillus brevis ATCC 8287 and Lactobacillus reuteri E97849, and a broad range of other lactic acid bacteria. These CDM allowed efficient protein radiolabelling, requiring as little as 200 mul of logarithmic culture and pulse-chase labelling of 20 min to detect c. 300 distinct protein spots in a mini-scale 2D-gel. Proteins including DnaK, GroEL and ClpATPases were identified from the 2D-gels by immunoblotting.

CONCLUSIONS

Radiolabelling coupled with 2D gel electrophoresis provides a sensitive means to monitor changes in protein synthesis rates in probistic lactobacilli.

SIGNIFICANCE AND IMPACT OF THE STUDY

Efficient tools for proteomic analyses of probiotic Lactobacillus were developed and applied for stress-response studies.

Suplementação de iogurte de soja com frutooligossacarídeos: características probióticas e aceitabilidade

OBJETIVO: Foram avaliadas as características probióticas dos microorganismos utilizados no preparo de iogurte de soja suplementado com os prebióticos oligofrutose e inulina (frutooligossacarídeos), suas características físico-químicas, microbiológicas e índice de aceitação. MÉTODOS: A formulação contendo extrato de soja em pó, oligofrutose e inulina, obtida por fermentação durante seis horas, em estufa mantida à temperatura de 42ºC, foi caracterizada e comparada a uma formulação de iogurte de soja sem suplementação quanto à viscosidade, perfil de textura e características probióticas. RESULTADOS: O fermento misto utilizado no preparo do iogurte (Lactobacillus bulgaricus e Streptococcus thermophilus) apresentou resistência à bile e ao ácido. Os prebióticos mantiveram a viabilidade das bactérias láticas até o 28º dia de armazenamento, em nível superior ao necessário para caracterizar um alimento probiótico. O iogurte suplementado apresentou pH de 4,63 e acidez de 0,37%, maior viscosidade, coesividade e adesividade e menor dureza que o iogurte sem suplementação. O índice de aceitação do iogurte de soja suplementado com prebióticos foi de 71,20%. CONCLUSÃO: Lactobacillus bulgaricus e Streptococcus thermophilus são probióticos e frutooligossacarídeos são ingredientes que mantêm a viabilidade das bactérias láticas no iogurte de soja, propiciando a formulação de um produto com boa aceitabilidade.

Survival of probiotic lactobacilli in acidic environments is enhanced in the presence of metabolizable sugars

Lactobacillus rhamnosus GG is an industrially significant probiotic strain with proven health benefits. In this study, the effect of glucose on L. rhamnosus GG survival was analyzed in simulated gastric juice at pH 2.0. It was found that the presence of 19.4 mM glucose resulted in up to 6-log10-enhanced survival following 90 min of exposure. Further work with dilute HCl confirmed that glucose was the sole component responsible. Comparative analysis with other Lactobacillus strains revealed that enhanced survival was apparent in all strains, but at different pH values. The presence of glucose at concentrations from 1 to 19.4 mM enhanced L. rhamnosus GG survival from 6.4 to 8 log10 CFU ml(-1) in simulated gastric juice. The mechanisms behind the protective effect of glucose were investigated. Addition of N',N'-dicyclohexylcarbodiimide to simulated gastric juice caused survival to collapse, which was indicative of a prominent role in inhibition of F0F1-ATPase. Further work with neomycin-resistant mutants that exhibited 38% to 48% of the F0F1-ATPase activity of the parent confirmed this, as the survival in the presence of glucose of these mutants decreased 3 x 10(6)-fold compared with the survival of the wild type (which had a viability of 8.02 log10 CFU ml(-1)). L. rhamnosus GG survival in acidic conditions occurred only in the presence of sugars that it could metabolize efficiently. To confirm the involvement of glycolysis in the glucose effect, iodoacetic acid was used to inhibit glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. The reduction in GAPDH activity caused survival to decrease by 8.30 log10 CFU ml(-1) in the presence of glucose. The data indicate that glucose provides ATP to F0F1-ATPase via glycolysis, enabling proton exclusion and thereby enhancing survival during gastric transit.

Surface display of foreign epitopes on the Lactobacillus brevis S-layer

So far, the inability to establish viable Lactobacillus surface layer (S-layer) null mutants has hampered the biotechnological applications of Lactobacillus S-layers. In this study, we demonstrate the utilization of Lactobacillus brevis S-layer subunits (SlpA) for the surface display of foreign antigenic epitopes. With an inducible expression system, L. brevis strains producing chimeric S-layers were obtained after testing of four insertion sites in the slpA gene for poliovirus epitope VP1, that comprises 10 amino acids. The epitope insertion site allowing the best surface expression was used for the construction of an integration vector carrying the gene region encoding the c-Myc epitopes from the human c-myc proto-oncogene, which is composed of 11 amino acids. A gene replacement system was optimized for L. brevis and used for the replacement of the wild-type slpA gene with the slpA-c-myc construct. A uniform S-layer, displaying on its surface the desired antigen in all of the S-layer protein subunits, was obtained. The success of the gene replacement and expression of the uniform SlpA-c-Myc recombinant S-layer was confirmed by PCR, Southern blotting MALDI-TOF mass spectrometry, whole-cell enzyme-linked immunosorbent assay, and immunofluorescence microscopy. Furthermore, the integrity of the recombinant S-layer was studied by electron microscopy, which indicated that the S-layer lattice structure was not affected by the presence of c-Myc epitopes. To our knowledge, this is the first successful expression of foreign epitopes in every S-layer subunit of a Lactobacillus S-layer while still maintaining the S-layer lattice structure.