Characterisation of Bacteriocins Produced by Lactobacillus spp. Isolated from the Traditional Pakistani Yoghurt and Their Antimicrobial Activity against Common Foodborne Pathogens (original) (raw)
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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
Bacteriocin Profiling of Probiotic Lactobacillus spp. Isolated from Yoghurt
Bacteriocin producing Lactobacillus spp. isolated from yoghurt, showed wide range of antimicrobial activity against some major food borne pathogens. Antimicrobial assay was conducted by modified agar overlay method and well diffusion method. Isolate 3 showed highest (42 mm) antimicrobial activities and isolate 4 showed lowest (15 mm) antimicrobial activities against test organisms. Bacillus subtilis showed the highest and Staphylococcus aureus showed the least susceptibility to the bacteriocins of isolated Lactobacillus spp. Cell extract & culture supernatant of isolates also showed antimicrobial activity. Bacteriocins were isolated from cell lysate of Lactobacillus spp. & separated by SDS-PAGE. All the isolates produced bacteriocins of 94 kDa, 60 kDa & 45 kDa molecular weight intracellularly& crude extracts of these bacteriocins showed considerable antimicrobial activity against test pathogens. This study revealed the possibility of bacteriocin as bio-preservatives for food stuffs.
Screening and Isolation of Lactobacillus from Novel Sources for Production of Bacteriocins
International Journal of Scientific & Engineering Research, 2017
Bacteriocins are primary metabolites which are synthesized in the ribosome of bacteria. These antimicrobial bioactive peptide substances kill or inhibit the growth of other closely related bacteria. The antimicrobial property of bacteriocins is used in the food industry, treatment of pathogen associated diseases, cancer therapy etc. Along with these applications of bacteriocins, they are also referred as next wave of conventional antibiotics. Bacteriocins fall under 'GRAS' (Generally Recognised as Safe) category as they usually have no side effects on the humans. In this study, bacteriocin producing bacteria were isolated with an aim of identifying a novel bacteriocin. The sources selected were paneer (cottage cheese) and Sauerkraut as they are rich in Lactic Acid Bacteria (LAB). The bacteriocin produced from these sources was tested for their inhibitory activity against food spoiling pathogens like Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus using Agar Well Diffusion Technique. Properties of the obtained bacteriocin were also tested. Future studies include extraction and SDS PAGE, HPLC of the extracted bacteriocin.
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.
Characterization of some bacteriocins produced by lactic acid bacteria isolated from fermented foods
World Journal of Microbiology and Biotechnology, 2014
Lactic acid bacteria (LAB) isolated from different sources (dairy products, fruits, fresh and fermented vegetables, fermented cereals) were screened for antimicrobial activity against other bacteria, including potential pathogens and food spoiling bacteria. Six strains have been shown to produce bacteriocins: Lactococcus lactis 19.3, Lactobacillus plantarum 26.1, Enterococcus durans 41.2, isolated from dairy products and Lactobacillus amylolyticus P40 and P50, and Lactobacillus oris P49, isolated from bors. Among the six bacteriocins, there were both heat stable, low molecular mass polypeptides, with a broad inhibitory spectrum, probably belonging to class II bacteriocins, and heat labile, high molecular mass proteins, with a very narrow inhibitory spectrum, most probably belonging to class III bacteriocins. A synergistic effect of some bacteriocins mixtures was observed. We can conclude that fermented foods are still important sources of new functional LAB. Among the six characterized bacteriocins, there might be some novel compounds with interesting features. Moreover, the bacteriocin-producing strains isolated in our study may find applications as protective cultures.
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 Lactic Acid Bacteria and Extraction of Bacteriocin Protein
Advances in Bioscience and Biotechnology, 2020
Biopreservation systems in foods are of increasing interest for industry and consumers. Bacteriocin producing Lactobacillus spp. is considered Generally Recognize as Safe (GRAS), useful to control the fast development of pathogens and spoiling microbes in food and feed. Lactobacillus spp. were isolated from traditional winter fermented vegetable cucumber & carrot by the use of selective media. Especially De Man, Rogosa and Sharpe (MRS) Agar media were used to isolate the Lactobacillus species. Morphologically identify by gram staining & colony morphology. Biochemically recognize by catalase, oxidase, MRVP & carbohydrate fermentation test. Antimicrobial activity of Lactobacillus spp. was confirmed by Well Diffusion Method. Molecular characterization of bacteriocin protein and molecular weight determination by SDS PAGE method. The isolate were found to be facultative anaerobic, Gram-positive, and catalase negative. The result of antimicrobial activity measurement by the Arbitrary Unit (AU/ml) of zone of the inhibition. Six isolate found from the sample but most activities exhibited isolate 4 against Bacillus megaterium (55 mm) zone of diameter. The molecular weight of the washed bacteriocin was calculated to be about 40 kDa (Isolate 1) and 15 kDa & 30 kDa (Isolate 5). Bacteriocin protein reduces chemical preservatives and uses in future as biopreservative in food industry.
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