Bacteriocin Profiling of Probiotic Lactobacillus spp. Isolated from Yoghurt (original) (raw)
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BioMed Research International
Lactic acid bacteria (LAB) are widely known for their probiotic activities for centuries. These bacteria synthesise some secretory proteinaceous toxins, bacteriocins, which help destroy similar or interrelated bacterial strains. This study was aimed at characterising bacteriocins extracted from Lactobacillus spp. found in yoghurt and assessing their bactericidal effect on foodborne bacteria. Twelve isolated Lactobacillus spp. were examined to produce bacteriocins by the organic solvent extraction method. Bacteriocins produced by two of these strains, Lactobacillus helveticus (BLh) and Lactobacillus plantarum (BLp), showed the most significant antimicrobial activity, especially against Staphylococcus aureus and Acinetobacter baumannii. Analysis of SDS-PAGE showed that L. plantarum and L. helveticus bacteriocins have a molecular weight of ~10 kDa and ~15 kDa, respectively. L. plantarum (BLp) bacteriocin was heat stable while L. helveticus (BLh) bacteriocin was heat labile. Both bacter...
African Journal of Microbiology Research, 2011
Lactic acid bacteria (LAB) commonly used in food, as starter cultures are known to produce antimicrobial substances such as bacteriocins and have great potential as food bio-preservatives. Yogurt is a probiotic dairy product having Lactobacillus bulgaricus as natural source for fermentation. The aim of this study was to determine the antimicrobial activity of bacteriocin, produced by Lactobacillus bulgaricus isolated from yogurt and tested against pathogenic organisms. The identification of the culture was based on characteristics of the strains of Lactobacillus spp. on the basis of microscopy (morphology), Gram straining, growth at 37 and 45°C, fermentation of different carbohydrate sources and growth in MRS broth. On the basis of all of the identification tests, one strain isolated from the yogurt was identified as L. bulgaricus. Culture supernatants were obtained from the sixty out of hundred isolates of Lactobacillus spp. exhibited varying degrees of inhibitory activity against strains of Bacillus subtilis, ATCC #6633, Escherichia coli, ATCC, #10536, Salmonella typhi, ATCC# 19430, Staphylococcus aureus, ATCC #6538, Vibrio cholerae, ATCC #25870. Specifically, Vibrio cholerae was found most sensitive to bacteriocin, exhibiting maximum zone of inhibition 18.3 mm.
African Journal of …, 2011
Lactic acid bacteria (LAB) commonly used in food, as starter cultures are known to produce antimicrobial substances such as bacteriocins and have great potential as food bio-preservatives. Yogurt is a probiotic dairy product having Lactobacillus bulgaricus as natural source for fermentation. The aim of this study was to determine the antimicrobial activity of bacteriocin, produced by Lactobacillus bulgaricus isolated from yogurt and tested against pathogenic organisms. The identification of the culture was based on characteristics of the strains of Lactobacillus spp. on the basis of microscopy (morphology), Gram straining, growth at 37 and 45°C, fermentation of different carbohydrate sources and growth in MRS broth. On the basis of all of the identification tests, one strain isolated from the yogurt was identified as L. bulgaricus. Culture supernatants were obtained from the sixty out of hundred isolates of Lactobacillus spp. exhibited varying degrees of inhibitory activity against strains of Bacillus subtilis, ATCC #6633, Escherichia coli, ATCC, #10536, Salmonella typhi, ATCC# 19430, Staphylococcus aureus, ATCC #6538, Vibrio cholerae, ATCC #25870. Specifically, Vibrio cholerae was found most sensitive to bacteriocin, exhibiting maximum zone of inhibition 18.3 mm.
ANTIBACTERIAL ACTIVITY OF BACTERIOCIN PRODUCING Lactobacillus spp., FROM VARIOUS MILK SAMPLES
Bacteriocin are highly specific antibacterial protein (polypeptides) produced by gram positive bacteria ,in particular the lactic acid bacteria display fairly broad inhibitory spectra with food preservative and therapeutic potentials. This work aims at to isolate bacteriocin-producing Lactobacillus spp., and to determine the antibacterial activity against pathogenic bacteria. This work involves methodology as follows Lactobacills spp., was isolated from various milk samples by using MRS Agar (Hi-media, India) at 37°C for 48h. The isolates were identified by using conventional biochemical tests. Antibacterial characteristics of bacteriocin were studied by agar well diffusion method and it partially purified by Ammonium sulphate precipitation and dialyzed. The present study revealed that the Lactobacillus spp., strain isolated from various milk samples was capable of producing bacteriocin and inactivating the widest range of pathogenic bacteria. Totally 48 isolates of Lactobacillus spp., was identified in that only 8 (17%) Lactobacillus spp., have the antibacterial activity against pathogenic bacteria. The study revealed that the antibacterial property of bacteriocin act as a food preservative agent against pathogenic microorganisms.
IP Innovative Publication Pvt. Ltd., 2018
Lactobacilli are a group of bacteria that are ubiquitous and contribute to the normal microbial flora of human beings. They are Generally Regarded as Safe (GRAS) and are not lethal to host. Bacteriocins are ribosomally synthesized antimicrobial peptides produced by Lactic Acid Bacteria (LAB) that exhibit antagonistic activity against food contaminating microorganisms and inhibit similar or closely related bacterial strains. Hence, these bacteriocins are considered bio-preservative and are demonstrated as food preservatives, as therapeutics for veterinary and medicinal uses or as phytosanitary means for plant protection. The present study involved isolation of Lactobacillus species from dairy samples, purification of bacteriocin and the study of antagonistic activity against food borne pathogens. The study showed that purified bacteriocin exhibited inhibitory activity against Escherichia coli and Shigella flexneri. Keywords: Bacteriocin, Lactic Acid bacteria, Pathogens, Cell free supernatants
EVALUATION OF ANTIBACTERIAL ACTIVITY OF BACTERIOCIN PRODUCING LACTOBACILLI FROM DAIRY COW MILK
The lactic acid bacteria were isolated and identifed such as (Lactococcus lactis, Lactobacillus bulgaricus, Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus fermentum from raw cow milk. Among our study, a positive correlation was observed the efficacy of bacteriocin is was noticed LAB (Lactococcus lactis, Lactobacillus bulgaricus, Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus fermentum) isolated from raw cow milk. In Lactococcus lactis had exhibid a better antibacterial activity on Staphylococcus aureus and Proteus vulgaris. The extracted compounds shows antibacterial activity against to the spoilage bacteria and enteric pathogenic microorganisms. In an attempt to differentiate the effect of lactic acid and bacteriocins produced by Lactobacilli that effect of heated neutralized filtrates on used test microorganisms indicated that the inhibition of these microorganisms may be due to effect of Bacteriocins. The Lactic acid bacteria which produce antibacterial compounds like Bacteriocin most widely used in food production. Consequently, in this study, we focused on an approach to isolate and determine the Bacteriocin producing ability of Lactobacilli from dairy milk sample. Bacteriocin production were of commercially valuable and developing production now a days. The results obtained from this study, the isolated Bacteriocin producing species of Lactobacilli play important role in the preservation of fermented food which is usually achieved by inhibition of contaminating spoilage bacteria such as Staphylococcus aureus, Bacillus cereus, E. coli, Proteus vulgaris and Pseudomonas aeruginosa. KEYWORDS:Raw cow milk, Total cell count, Bacteriocin, Lactobacilli, Antibacterial activity
AMB Express, 2012
The biopreservation of foods using bacteriocinogenic lactic acid bacteria (LAB) isolated directly from foods is an innovative approach. The objectives of this study were to isolate and identify bacteriocinogenic LAB from various cheeses and yogurts and evaluate their antimicrobial effects on selected spoilage and pathogenic microorganisms in vitro as well as on a food commodity.LAB were isolated using MRS and M17 media. The agar diffusion bioassay was used to screen for bacteriocin or bacteriocin-like substances (BLS) producing LAB using Lactobacillus sakei and Listeria innocua as indicator organisms. Out of 138 LAB isolates, 28 were found to inhibit these bacteria and were identified as strains of Enterococcus faecium, Streptococcus thermophilus, Lactobacillus casei and Lactobacillus sakei subsp. sakei using 16S rRNA gene sequencing. Eight isolates were tested for antimicrobial activity at 5°C and 20°C against L. innocua, Escherichia coli, Bacillus cereus, Pseudomonas fluorescens, ...
2018
Strain selected for this study was isolated and named as sl36, from samples of goat milk collected from stainless steel drums in a dairy farm (San Luis, Argentina). The LAB strain was biochemically typified as Lactobacillus fermentum and designated as L. fermentum sl36. This identification was confirmed by 16S rRNA full sequences. The selected strain showed antimicrobial activity against food-borne pathogens, Listeria monocytogenes, Listeria innocua, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. The inhibitory activity was lost after treatment with trypsin, which indicates that this activity is due to a protein nature substance compatible with bacteriocins produced by Gram positive bacteria.The inhibitory substance was stable at different pH and temperatures. Perishable food samples (semi-hard cheese, cream, cooked pork shoulder) were treated with cell free supernatant from studied strain and then with indicator S. aureus and E. faecalis bacteria suspensions. Lactobacillus fermentum sl36 caused the inhibition of the growth of E. faecalis and S. aureus in the treated foods. Our work shows that it is possible to increase the safety of food perishable directly using the bacteriocins produced by the LAB strains, difference from the more frequent practice of using the bacteria themselves as probiotics.
International Journal of Biology, 2011
The intent of the study is to determine the antimicrobial activity of Lactobacillus producing bacteriocin isolated from raw milk of cattle's like cow, buffalo and goat and to characterize the bacteriocin. Hundred Lactobacillus isolates (50 isolates from cow, 22 isolates from buffalo and 28 isolates from goat) based upon the distinct morphology were isolated from the samples and identified as Lactobacilli according to phenotypic characteristics. Bacteriocin producing organisms were screened by Agar spot assay test. Ten strains were able to produce bacteriocin whose antibacterial activity was analyzed by agar well diffusion assay test against indicator organisms and pathogenic organisms. Bacillus mycoides, Staphylococcus aureus, Streptococcus faecalis, Klebsiella pnuemoniae and Proteus vulgaris were inhibited by the isolates. Bacillus amyloliquifaciens, Bacillus cereus, Salmonella typhi and Pseudomonas aeruginosa, were resistant to the isolates producing antibacterial substances. The antibacterial protein bacteriocin was characterized based on the sensitivity to heat, different pH values, acid neutralization test, sensitivity to chloroform, NaCl and incubation period. Lactobacilli from raw milk samples that inhibited certain pathogenic organisms by producing bacteriocin may be beneficial for a probiotic culture to be triumphant in colonizing and to contend with pathogens.
African Journal of Microbiology Research, 2012
Lactic acid producing bacteria was isolated from Whey. The isolated strain Lactobacillus fermentum KN02 was potent producer of bacteriocins. Bacterioicin produced by the isolate KN02 had a large spectrum of inhibition against food spoilage microorganisms (Escherchia coli, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis, Pseudomonas aeuroginosa, Klebsiella pneumonia, Bacillus cereus). The bacterioicin inhibited the growth of pathogens but it showed high activity against Bacillus. The bacteriocins were found to be heat stable at 100°C. The maximum antimicrobial activity was retained within the pH range of 2, and completely affected by proteolytic enzyme (papain). Bacteriocins are used to control the frequent development of pathogens and spoiling microorganism in food and feed. Growth of L. fermentum KN02 was inhibited only by few antibiotics suggesting that the strain may be used as a probiotic by the individual receiving medical treatment. The new bacterioicin producing L. fermentum KN02 has been selected for identification and application of bacteriocins to food products (Milk and Mushroom) which reduces the growth of pathogens. The bacteriocins producers L. fermentum KN02 was identified on the basis of phenotypic analysis and 16S rRNA sequences.