Production Of Bacteriocin-like Substances Research Articles

Respiratory microbiota of healthy broilers can act as reservoirs for multidrug-resistant Escherichia coli

This study aimed at evaluate the presence and to study characteristics of Escherichia coli in the respiratory system microbiota of healthy broilers. Trachea, air sacs, and lungs of 20 broilers were analyzed at 21 days of age, reared in experimental conditions, without receiving antimicrobials. E. coli strains were isolated and identified using conventional bacteriology through morphological and biochemical characterization. The production of bacteriocin-like substances, the presence of virulence-associated genes (VAGs) of APEC (Avian Pathogenic Escherichia coli) predictors, and the antimicrobial susceptibility were evaluated. E. coli was found in 85 % of the animals (17/20), in the trachea, air sacs or lungs; and it was not found in 15 % of the animals (3/20). A total of 34 isolates were recovered, 13 from the air sacs, 13 from the lungs, and 8 from the trachea, which showed no production of bacteriocin-like substances nor virulence genes associated with APEC. Most isolates, 59 % (20/34), showed resistance to at least one of the tested antimicrobials, and six multiresistant strains were identified. The results demonstrated that strains of E. coli were commensal of the respiratory microbiota, and that they did not present pathogenicity to the host, since there were no clinical signs of disease, macroscopic lesions in the organs of the evaluated broilers, production of bacteriocin-like substances, nor virulence-associated genes considered as predictors of APEC in bacteria. These strains of E. coli were mostly susceptible to antimicrobials. However, the occurrence of multidrug-resistant strains suggests that these animals can act as reservoirs of resistant to antimicrobials E. coli.

Characterization, Toxicity, and Optimization for the Growth and Production of Bacteriocin-like Substances by Lactobacillus curvatus.

This study aimed to characterize, evaluate toxicity and optimize the conditions for the growth and production of bacteriocin-like substances by Lactobacillus curvatus P99. The antibacterial activity of the cell-free supernatant (CFS) containing bacteriocin-like substances was evaluated by the agar diffusion technique. The stability of the CFS was also examined after heat treatment, refrigeration, freezing, pH variations, and treatment with different chemical substances. The toxic effect of CFS on Drosophila melanogaster diet was determined by calculating the survival rate of the flies. The effects of pH, temperature, and incubation time were the parameters used to optimize cell growth and production of bacteriocin-like substances through response surface methodology. The CFS was stable for 36weeks under freezing and refrigeration, as well as under heat treatment, in acidic and basic pH and for all chemical substances tested. Fewer than 50,000AU/mL of CFS added to D. melanogaster diet showed no toxic effect. The optimum growth condition was pH6.3 at 29.3°C for 18.6h, and the optimum production of bacteriocin-like substances was under pH6.22 at 30.6°C for 17.9h. The data on the optimization of cell growth and the characterization and optimization of bacteriocin-like substances provided information to support the industrial-scale production of this microorganism and its metabolites.

Production of Bacteriocin-like Substances by <i>Bacillus</i> Spp. JY-1 in Soy Whey

Soy whey is a by-product from the processing of soybean products, which is generally discarded and considered as waste. In recent years, a large number of bacteriocins produced by bacteria have been described. However, the production of bacteriocins in soy whey has not yet reported. Bacteriocin-like substance producing B. spp JY-1 was isolated from Chinese traditional fermented soybean (douchi) in previous study. In present study, the antimicrobial spectrum, and the effect of enzymes, pH and heat on the antibacterial activity of bacteriocin-like substance produced by B. spp JY-1 were evaluated. Then, the effects of supplement of carbon and nitrogen sources on the production of bacteriocin-like substances in soy whey were also investigated. Results obtained indicated that bacteriocin-like substance in cell-free supernatant of JY-1 exhibited broad inhibitory spectrum both against some food-borne pathogens. The bacteriocin-like substance JY-1 was sensitive to trypsin and pepsin, but stable between pH 2.0-10, and heat resistance (65-105°C). In addition, the production of bacteriocin-like substance JY-1 started at the early exphonential phase and reached its maximum at the stationary phase. The antimicrobial activity of cell-free supernatant of JY-1 cultured in soy whey was observed. The supplement of soluble starch or beef extract in soy whey yielded a higher production of bacteriocin-like substance. The results indicated that the bacteriocin-like substance JY-1 may be a potential candidate for alternative agent to control important food pathogens, and the soy whey has potential for production of bacteriocins.

Probiotics study with Streptococcus salivarius and its ability to produce bacteriocins and adherence to KB cells

Abstract Introduction Streptococcus salivarius is a dominant oral species and the best suitable candidate for probiotic of the oral cavity. Since Streptococcus salivarius is able to produce bacteriocins against Streptococcus pyogenes interest has been focused on the use of it as a probiotic to avoid sore throats by Streptococcus pyogenes. Objective This study is for selecting Streptococcus salivarius strains for potential use as probiotics for the oral mucosa, that is, production of bacteriocin against Streptococcus pyogenes and the ability to bind to KB cells. Material and method Tongue material from 45 students was collected and seeded on Mitis Salivarius Agar plaques. The strains were tested by the production of bacteriocin-like substances (BLIS) against S. pyogenes, biochemically and PCR for identification of S. salivarius. The best strains were tested for adherence to KB cells. Briefly, S. salivarius strains were cultured in broth, washed and suspended at 108cells/ml. KB cells were inoculated into plaques, washed and incubated with the bacteria, for adhesion. These were washed for lysis of the KB cells and release bacteria for determination of CFU. Result The bacteriocin test showed that 133 strains presented inhibition of S. pyogenes. The samples tested for adhesion to KB cells, presented different profiles and only three strains presenting high adhesion capacity. Conclusion The selection of strains of Streptococcus salivarius with high inhibitory activity against Streptococcus pyogenes, as well as adherence to KB cells leads us to the next future step, that is, to use the best strains for in vivo colonization tests

ANTIMICROBIAL PROPERTIES AND PROBIOTIC POTENTIALS OF LACTIC ACID BACTERIA ISOLATED FROM RAW BEEF IN IBADAN, NIGERIA

Lactic acid bacteria (LAB) are important microflora in raw meat and fermented meat products. They exhibit antagonistic activities against undesirable microorganisms and are highly valued for their probiotic properties. LAB associated with raw beef from two major abattoirs in Ibadan, Nigeria were assessed for antimicrobial activity and probiotic potential. Agar-spot assay showed that 8 of 23 LAB isolates inhibited the growth of at least one of Escherichia coli, Listeria monocytogenes, K. pneumoniae and S. aureus. Selected antibacterial isolates were identified based on API50CHL as Lactobacillus plantarum (3), Pediococcus pentosaceus (2) Lactobacillus paracasei (1), Leuconostoc lactis (1) and Carnobacterium sp. (1). Antimicrobial activities were revealed to be dependent on acidification and production of bacteriocin-like substances. Five LAB strains lowered the pH of medium to < 4 within 24 h, with Leuconostoc lactis Csu12 broth culture having the lowest pH (3.04 ±0.08). Bacteriocin-like activity was displayed by six LAB strains against at least one indicator organism. The antibacterial isolates tolerated low pH and different bile concentration (0.5 and 1%). In addition, they showed different levels of hydrophobicity to xylene. Results from this study suggest the consideration of our resident LAB from meat as novel protective cultures and probiotic candidates in the food industry.

In Vitro antibacterial activity of lactic acid bacteria isolated from goat’s raw milk of Mostaganem (West Algeria) against Gram negative bacteria responsible for urinary tract infections

Urinary tract infections (UTI) are a serious bacterial pathological challenges all over the world, leading to respiratory infections, that’s why new strategies don’t cease to develop. Lactic acid bacteria having shown beneficial effects for years in various areas, may prove to be excellent candidates in medical field. The current research focused on the selection of lactic acid bacteria having the potential of an antibacterial activity against Gram negative bacteria responsible for UTI, for an eventual use as a therapeutic agent. A total of 40 isolates were isolated from goat’s raw milk of Mostaganem (West Algeria). In vitro tests were conducted in order to determine the efficiency of the isolates to produce antibacterial agents in interaction with uropathogens. Among 40 isolates, only 10 isolates identified as Lactobacilli and Lactococci were performant. The Screening showed that the inhibitor agent was proteinaceous substance. Therfore, it is noted that a treatment with presence of LAB is very encouraging as a result of the production of bacteriocin-like substance. On the other hand, LAB can be considered as a good alter-native to the large extent to the antibiotics in the treatment of UTI.

The potential influence of two Enterococcus faecium on the growth of Listeria monocytogenes

Two strains of Enterococcus faecium isolated from meat products were analyzed for the antimicrobial activity, safety and inhibition of Listeria monocytogenes in co-culture experiments. The production of bacteriocin-like substances and the presence of enterocin A, B, P genes (entA, entB, entP) were confirmed in E. faecium B1 whilst E. faecium B2 harbored neither of these characteristics. None of E. faecium strains harbored the virulent determinants studied (esp, hylEfm, IS 16, VanA and VanB) and were sensitive to most common antibiotics. In the co-culture experiment, both E. faecium B1 and E. faecium B2 had an inhibition effect towards L. monocytogenes. However, E. faecium B1 inhibited the growth of L. monocytogenes in the early stages of co-culture, and then probably reduced the cell counts of L. monocytogenes until an undetectable level after four days. Thus the cell counts of L. monocytogenes stayed at the initial inoculum level during the co-culture with E. faecium B2, suggesting that the bacteriocin-like substance played an important role in the inhibition effect. Meanwhile, the pH in co-culture declined lower than that in mono-culture in the early days, indicating the production of acid might participate in the inhibition process. Also, E. faecium B1 could be considered to be used as an effective potential bio-protective culture, so as to improve the safety of meat products.

Technological Characterization of Lactic Acid Bacteria Isolated from Beef Stored on Vacuum-Packaged and Advanced Vacuum Skin Packaged System

A total of 91 Lactic Acid Bacteria (LAB) isolated from meat packaged using traditional vacuum packaging (42 strains) or an advanced vacuum skin packaging system (49 strains) were characterised in terms of gas production, proteolytic and lipolytic activity, production of hydrogen peroxide, histamine and bacteriocin-like substances, and haemolytic activity. Thermal resistance of all isolated bacteria was also analysed. No differences were found for most parameters; with the exception of a higher production of bacteriocin-like substances in LAB isolated from meat packaged using advanced vacuum skin packaging than those obtained for isolated from meat packaged using traditional vacuum packaging. LAB isolated from advanced vacuum skin packaged meat had higher thermal resistance than LAB isolated from meat packaged with the traditional vacuum method, both at 55oC (14.09 min vs. 11.17 min) and at 60oC (6.87 min vs. 4.64 min). These data could contribute to an explanation for the longer shelf life of meat packed using advanced vacuum skin packaging compared to meat packed with traditional vacuum packaging.

A bacteriocin-like substance produced from Lactobacillus pentosus 39 is a natural antagonist for the control of Aeromonas hydrophila and Listeria monocytogenes in fresh salmon fillets

We studied the ability of Lactobacillus pentosus 39, a BLS (Bacteriocin-like substance)-producing strain, to control the growth of Aeromonas hydrophila ATCC 14715 and Listeria monocytogenes ATCC 19117 artificially added to fresh salmon fillets at refrigeration temperatures and under simulated cold-chain break conditions.At refrigeration temperatures, Lb. pentosus 39 protective culture and its putative bacteriocin significantly reduced A. hydrophila counts compared with the control (2.1 and 1.4 log CFU/g reductions, respectively). Similar behaviour was observed for L. monocytogenes (3.6 and 1.3 log CFU/g reductions, respectively).Under simulated cold-chain break conditions, an increase in temperature (30°C for 12h) produced an evident increase in the development of A. hydrophila, L. monocytogenes, but also of Lb. pentosus 39, with a consequent increase in BLS production. This condition resulted in a greater reduction of both pathogens compared with samples stored at 4°C throughout the experiment (2.8 log CFU/g reduction for A. hydrophila, 5.8 log CFU/g reduction for L. monocytogenes). In samples treated with the putative bacteriocin alone, a less marked decrease was observed.Our study demonstrates the capability of Lb. pentosus 39 to control the growth of psychrotrophic bacteria in an experimental seafood model system. A similar biopreservation technology could provide more prolonged shelf-life during storage of ready-to-eat seafood, ensuring safety, even under extreme conditions.

TSST-1, enterotoxin and bacteriocin-like substance production by Staphylococcus aureus isolated from foods

The production of Toxic Shock Syndrome Toxin-1 (TSST-1), enterotoxins and bacteriocin-like substances was evaluated in 95 strains of Staphylococcus aureus recovered from raw bovine milk (n=31) and from food samples involved in staphylococcal food poisoning (n=64). Enterotoxigenicity tests with the membrane over agar associated to optimal sensibility plate assays were performed and showed that 96.77% of strains recovered from milk and 95.31% from food samples produced enterotoxins A, B, C, D or TSST-1. Reference strains S. epidermidis, Bacillus cereus, Listeria monocytogenes, Lactobacillus casei, Pseudomonas aeruginosa, S. aureus, Salmonella Typhimurium, Escherichia coli, Enterococcus faecalis and Bacteroides fragilis were used as indicator bacteria in the antagonistic assays, the first five being sensitive to antagonistic substances. Brain heart infusion agar, in pH values ranging from 5.0 to 7.0 in aerobic atmosphere showed to be the optimum condition for antagonistic activity as evaluated with the best producer strains against the most sensitive indicator bacterium, L. monocytogenes. Sensitivity to enzymes confirmed the proteinaceous nature of these substances. Neither bacteriophage activity nor fatty acids were detected and the antagonistic activity was not due to residual chloroform. Results did not establish a positive correlation between the bacteriocinogenic profile and toxigenicity in the tested S. aureus strains.

Probiotic properties of Enterococcus faecium CE5-1 producing a bacteriocin-like substance and its antagonistic effect against antibiotic-resistant enterococci in vitro

A bacteriocin-like substance (BLS) producing Enterococcus faecium CE5-1 was isolated from the gastrointestinal tract (GIT) of Thai indigenous chickens. Investigations of its probiotic potential were carried out. The competition between the BLS probiotic strain and antibiotic-resistant enterococci was also studied. Ent. faecium CE5-1 exhibited a good tolerance to pH 3.0 after 2 h and in 7% fresh chicken bile after 6 h, but the viability of Ent. faecium CE5-1 decreased by about 2–3 log CFU/ml after 2 h incubation in pH 2.5. It was susceptible to the antibiotics tested (tetracycline, erythromycin, penicillin G, and vancomycin). The maximum BLS production from Ent. faecium CE5-1 was observed at 15 h of cultivation. It showed activity against Listeria monocytogenes DMST17303, Pediococcus pentosaceus 3CE27, Lactobacillus sakei subsp. sakei JCM1157, and antibiotic-resistant enterococci. The detection by polymerase chain reaction (PCR) in the enterocin structural gene determined the presence of enterocin A gene in Ent. faecium CE5-1 only. Ent. faecium CE5-1 showed the highest inhibitory activity against two antibiotic-resistant Ent. faecalis VanB (from 6.68 to 4.29 log CFU/ml) and Ent. gallinarum VanC (from 6.76 to 4.31 log CFU/ml) after 12 h of co-cultivation. The results show the future possible use of Ent. faecium CE5-1 as a probiotic strain for livestock to control antibiotic-resistant enterococci.  

Identification of a new Bacillus licheniformis strain producing a bacteriocin-like substance

The emergence of antibiotic resistance has spurred a great number of studies for development of new antimicrobials in the past decade. The purpose of this study was to screen environmental samples for Bacillus strains producing potent antimicrobial agents. A new strain, which showed strong antimicrobial activity against Staphylococcus aureus and Salmonella enterica ser. Pullorum, was isolated from soil and designated as B116. This new isolate was identified as Bacillus licheniformis by morphological, biochemical and genetic analyses. The production of bacteriocin-like substance (BLS) started at early exponential phase and achieved highest level at early stationary phase. The BLS was precipitated by ammonium sulfate and its molecular mass was determined as ∼4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Culture supernatant of the new isolate exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria, including Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Micrococcus luteus, Escherichia coli, and Salmonella spp. The BLS was resistant to heat, acid and alkaline treatment. Activity of the BLS was totally lost after digestion by pronase and partially lost after digestion by papain and lipase. The new isolate and relevant BLS are potentially useful in food and feed applications.

Synergistic growth effect among bacteria recovered from root canal infections

The objective of this study was to determine the ecological relationships between bacterial species that colonize infected root canals. Root canal bacteria recovered from one patient with pulp canal necrosis were evaluated in vitro for synergistic and antagonistic activities determined by mono and co-culture growth kinetics and the production of bacteriocin-like substances using the double layer diffusion method. Peptostreptococcus prevotii triggered a significant increase of Fusobacterium nucleatum growth, while the former bacteria did not affect the growth of P. prevotii. The bacterial species did not produce antagonism activity against itself or against any of the other two species. Despite many studies have demonstrated the capability of root canal microorganisms to produce antagonistic substances, these in vitro experimental tests show the synergistic effect of P. prevotii on the growth of F. nucleatum.

The influence of growth conditions on enterocin-like production by Enterococcus faecium CWBI-B1430 and Enterococcus mundtii CWBI-B1431 isolates from artisanal Peruvian cheeses

Strains of Enterococcus faecium CWBI-B1430 and Enterococcus mundtii CWBI-B1431, isolated from artisanal-produced Peruvian cheeses, offer a broad potential application as food biopreservatives for heat-processing treatments. The aim of this work was to optimize the production conditions and medium composition for the production of bacteriocin-like substances (BLIS). The kinetics of the BLIS production for both strains is a growth-associated process, and the maximum inhibitory activity for E. faecium CWBI-B1430 and E. mundtii CWBI-B1431 was achieved after 9 and 8 h of fermentation, respectively. Temperature, initial pH, oxygen level, and their interactions all influence BLIS production for both strains; this influence was specific for each strain. The bacteriocin gene expression in a 20.0-L fermentor confirms previous work carried out by fermentation in the flask; the first reports of expression revealed mundticin KS from E. faecium and enterocin P from E. mundtii. Both strains demonstrated antilisteria activity and were multi-producers of enterocin. Furthermore, the study with whey milk as an inexpensive source of fermentable carbohydrates indicated lower BLIS production than that obtained with M17LG broth. The short chain fatty acid (SCFA) analyses offer a new alternative use for both strains, as strains probiotic, for propionic acid production.

Characterization and partial purification of a bacteriocin‐like substance produced by thermophilic Bacillus licheniformis H1 isolated from cow manure compost

The production and partial characterization of bacteriocin-like substances (BLSs) produced by bacteria isolated from cow manure compost were investigated. Eight BLS producers, which exhibited inhibitory activity against pathogenic bacteria, were isolated from cow manure compost at different stages of the composting process. The pile temperature ranged from 9.1 °C to 73.2 °C. The BLSs showed thermostability, but the BLS producers were not thermostable except for the H1 producer. Thermophilic Bacillus licheniformis H1 was further characterized. The culture supernatant of B. licheniformis H1 exhibited antagonistic activity against various species of Gram-positive bacteria such as Listeria monocytogenes ATCC19111 but not against Gram-negative bacteria except Pseudomonas fluorescens ATCC11251. Inactivation of bacteriocin-like activity by α-chymotrypsin, trypsin, and papain was highly significant (P<0.001). The BLS was found to be stable under a pH range from 3 to 9 and at temperatures up to 75 °C for 60 min, but it lost activity after being autoclaved at 121 °C for 15 min. The optimum production of BLS by B. licheniformis H1 was obtained at a temperature of 55 °C. Sodium dodecyl sulfate - polyacrylamide electrophoresis analysis of concentrated partially purified supernatants collected after resting the bacterial cells at 55 °C revealed a bacteriocin-like protein with a molecular mass of approximately 3.5 kDa. This study is the first report of a BLS from thermophilic B. licheniformis with an animal compost origin.

Synergistic growth effect among bacteria recovered from root canal infections.

The objective of this study was to determine the ecological relationships between bacterial species that colonize infected root canals. Root canal bacteria recovered from one patient with pulp canal necrosis were evaluated in vitro for synergistic and antagonistic activities determined by mono and co-culture growth kinetics and the production of bacteriocin-like substances using the double layer diffusion method. Peptostreptococcus prevotii triggered a significant increase of Fusobacterium nucleatum growth, while the former bacteria did not affect the growth of P. prevotii. The bacterial species did not produce antagonism activity against itself or against any of the other two species. Despite many studies have demonstrated the capability of root canal microorganisms to produce antagonistic substances, these in vitro experimental tests show the synergistic effect of P. prevotii on the growth of F. nucleatum.

Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

Lactic acid bacteria (LAB) were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS). The BLS produced by both isolates showed antimicrobial activity against Listeria monocytogenes, whereas that produced by L. plantarum LCN 17 presented higher stability to different temperature, pH and enzyme treatments. These strains present potential for production of BLS, and for use as starter cultures.

Lactic acid bacteria isolated from artisanal dry sausages: Characterization of antibacterial compounds and study of the factors affecting bacteriocin production

Lactic acid bacteria (LAB) were isolated from artisanal dry sausages sampled from north-eastern region of Chaco, Argentina. Among 141 isolates, 27 showed antimicrobial activity against Listeria innocua, Staphyloccus aureus or Brochothrix spp. One isolate, identified as Lb. curvatus/sakei, produced bacteriocin like substances (BLIS). These BLIS were heat stable, effective after refrigerated storage and freeze/thaw cycles and even active against pathogens when produced under refrigeration at 3% NaCl concentration. The influence of several factors on production of BLIS was assessed in MRS broth added with: EDTA, ascorbic acid, KCl, potassium sorbate, sodium citrate, 3 and 6% NaCl, Tween 20 or Brij 35. These additives showed different effects towards the effectiveness of the bacteriocin produced by Lb. sakei/curvatus against L. innocua and S. aureus. Conditions that provided high cell density favored high bacteriocin production. BLIS production by this LAB strain was greatly influenced by NaCl concentration and the presence of surfactants.

Isolation and identification of Enterococcus faecium from seafoods: Antimicrobial resistance and production of bacteriocin-like substances

A collection of isolates from uncooked seafoods (molluscs, fish, and fish fillets) were identified as Enterococcus faecium species and studied in further detail. Isolates were clustered in well-defined genomic groups according to food origin after ERIC-PCR analysis. Four isolates (FR 1-2, FB 1-3-B, FB 3-1, FTA 1-2) decarboxylated lysine, ornithine, and tyrosine. Isolate FR 1-2 also decarboxylated histidine. Most isolates were sensitive to antibiotics of clinical use, but resistance was detected more frequently towards nitrofurantoin (50%), erythromycin (33.33%) or rifampicin (33.33%) to quinupristin/dalfopristin (12.5%). Resistance to β-lactams or vancomycin was not detected. The enterococcal antigen A was the presumed virulence trait detected most frequently. None of isolates carried haemolysin/cytolysin genes. Twelve isolates produced anti-listerial activity. Among them, seven isolates also produced bacteriocin-like inhibitory substances against other enterococci, and one isolate was also able to inhibit Staphylococcus aureus. Three isolates only were active against Listeria monocytogenes, and two only were active against enterococci. One bacteriocinogenic isolate carried the enterocin A structural gene, but genes corresponding to other enterocins (EntB, EntP, EntQ, Ent1071, EntL50A/EntL50B, and Ent31) were not detected. Bacteriocin-producing enterococci lacking undesirable traits (such as antibiotic resistance or biogenic amine production) or their produced bacteriocins could be potential candidates to aid in preservation of seafoods and other food products as well.

Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese.

Lactic acid bacteria (LAB) were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS). The BLS produced by both isolates showed antimicrobial activity against Listeria monocytogenes, whereas that produced by L. plantarum LCN 17 presented higher stability to different temperature, pH and enzyme treatments. These strains present potential for production of BLS, and for use as starter cultures.