• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1836-1840
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• 2008

Bacteriocins are antimicrobial peptides that are produced by bacteria and toxic to bacterial strains closely related to the producer strain. It has previously been reported that Bacillus thuringiensis strain NEB17 and Bacillus thuringiensis subsp. kurstaki BUPM4 produce the bacteriocins thuricin 17 (3,162 Da) and bacthuricin F4 (3,160.05 Da), respectively. Here, we demonstrate that these bacteriocins have functional similarities and show a similar spectrum of antimicrobial activities against indicator strains. We also studied the effects of sterilization methods on the recovery and biological activities of these bacteriocins. They were completely degraded by autoclaving and the two were similarly affected by the tested filter membranes. Polyvinylidene fluoride (PVDF), polyestersulfone (PES), and cellulose acetate (CA) are suitable for filter sterilization of these bacteriocins. The two bacteriocins were stable across a range of storage conditions. These data will facilitate their utilization in food preservation or agricultural applications.

• Journal of Life Science
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• v.33 no.1
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• pp.91-101
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• 2023

Bacteriocins are antimicrobial peptides synthesized on ribosomes, produced by bacteria, that inhibit the growth of similar or closely related bacterial strains. Since the discovery of nisin, many bacteriocins with unique structures and various modes of antibacterial activity have been described, and genes encoding production, secretion, and immunity have been reported. Nisin is one of the bacteriocins applied in cheese, liquid eggs, sauces and canned foods. Many of the bacteriocins of the genus Bacillus belong to lantibiotics, which are modified peptides after translation. Other genus Bacillus also produce many non-lantibiotic bacteriocins. Bacteriocins of the genus Bacillus are sometimes becoming more important because of their broader antibacterial spectrum. Bacteriocins are considered attractive compounds in the food and pharmaceutical industries to prevent food spoilage and growth of pathogenic bacteria. Bacteriocins can be used as biological preservatives in a variety of ways in the food system. Biopreservation refers to extending shelf life and improving safety of foods using microorganisms and/or their metabolites. The demand for new antimicrobial compounds has generated great interest in new technologies that can improve food microbiological safety. Applications of bacteriocins are expanding from food to human health. Today, many researchers are shifting their interest in bacteriocins from food preservation to the treatment of bacteria that cause infections and antibiotic-resistant diseases. This exciting new era in bacteriocin research will undoubtedly lead to new inventions and new applications. In this review, we summarize the various properties and applications of bacteriocins produced by the genus Bacillus.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.269-277
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• 1996

Bacteriocins are proteins produced by a heterogeneous group of bacteria that have a bactericidal effect on closely related organisms. Recently, bacteriocins from lactic acid bacteria and other food-related organisms have been the subject of much research because of their potential as food biopreservatives. Various modifications of agar plate diffusion assays are the most widely used methods even though the limitations of such assays are generally recognized. The ability to obtain a concentrated crude preparation on bacteriocin by optimizing production parameters greatly simplifies recovery of bacteriocin on subsequent purification steps. Some studies performed to optimize bacteriocins have been purified to homogeneity, and the amino acid sequences of many of these purified bacteriocins have been determined. Obtaining characterization data on purified bacteriocin will minimize the risk of overlapping of research and confusion on identification of these compounds. Several me-chanisms leading to cell death have been hypothesized. These include depletion of the proton motive force(PMF) across the cell membrane: RNase and/or DNase activity within the sensitive cell; and pore formation and lysis of sensitive cells at the cell membrane.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.675-690
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• 2007

Bacteriocins in Gram-positive bacteria have attracted much attention because many have a strong antimicrobial activity also against bacteria outside the genera of the producers. Lantibiotics and the pediocin-like bactericins have attracted most attention since they kill a broad spectrum of Gram-positive bacteria including important pathogens. But many other promising Gram-positive bacteriocins have been thoroughly characterized. Recent studies have shown that bacteriocins may playa role in the intestinal flora to protect us against the food-borne pathogens. Bacterial genome sequencing has demonstrated that there may be an arsenal of such compounds and we are only seeing the top of the iceberg. The present review gives a short outlook of the field of bacteriocins with focus on lactic acid bacteria and includes recent findings.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.229-235
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• 2011

Antimicrobial peptides exhibit high levels of antimicrobial activity against a broad range of spoilage and pathogenic microorganisms. Compared with bacteriocins produced by lactic acid bacteria, antimicrobial peptides from the genus Bacillus have been relatively less recognized despite their broad antimicrobial spectra. These peptides can be classified into two different groups based on whether they are ribosomally (bacteriocins) or nonribosomally (polymyxins and iturins) synthesized. Because of their broad spectra and high activity, antimicrobial peptides from Bacillus spp. may have great potential for applications in the food, agricultural, and pharmaceutical industries to prevent or control spoilage and pathogenic microorganisms. In this review, we introduce ribosomally synthesized antimicrobial peptides, the lantibiotic bacteriocins produced by members of Bacillus. In addition, the biosynthesis, genetic organization, mode of action, and regulation of subtilin, a well-investigated lantibiotic from Bacillus subtilis, are discussed.

• Food Science of Animal Resources
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• v.38 no.1
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• pp.172-179
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• 2018

One of the critical limitations to use of bacteriocins produced by lactic acid bacteria as a substitute for chemical antibiotics is the narrow spectrum of their antibacterial activity. The aim of present study was isolation and molecular identification of bacteriocin-producing enterococci with broad antibacterial spectrum. Bacteriocin-producing bacteria were isolated from native dairies in Kerman. Bacteriocins were purified by ammonium sulfate method and the effects of them were investigated on different strains of bacteria. Also, the effects of pH and heat on produced bacteriocins were investigated. High level bacteriocin-producing isolates were identified based on molecular tests. A total of 15 strains of bacteriocin-producing Enterococcus were isolated initially. Enterococcus faecium C-2 and Y-1 strains produced bacteriocins with the highest antibacterial effect. The bacteriocins were stable in pH ranges from 2 to 12 and their antibacterial activity was maintained after autoclave treatment. The maximum bactericidal effect was observed against Listeria monocytogenes and Pseudomonas aeruginosa. In conclusion, use of these bacteriocins as a substitute for chemical antibiotics is recommended.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.305-315
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• 1994

Nineteen strains of bacteriocin-producing lactic acid bacteria were isolated from 432 Kimchi samples, and identified by the comprehensive biochemical and morphological tests verifying their cellular fatty acid composition. Using partially purified bacteriocins from these isolates, their inhibitory activities against other lactic acid bacteria and some pathogens, and sensitivity to enzyme and heat treatments were tested. The isolates were identified as Lactobacillus plantarum (2 strains), L curvatus (2 starins), L brevis (2 strains), Enterococcus faecium (6 strains), Leuconostoc mesenteroides subsp. mesenteroides (1 strain) and Lactobacillus sp. (6 strains). The bacteriocins produced by E. faecium strains provided the broadest spectrum of inhibition, affecting against other Gram-positive bacteria including lactic acid bacteria and health-threatening bacteria such as Clostridium perfringens and Listeria monocytogenes. The bacteriocins of Lactobacillus sp., L plantarum and L brevis strains were capable of inhibiting many strains of the lactic acid bacteria, whereas those of L curvatus and L mesenteroides subsp. mesenteroides strains were only inhibitory to a few strains. Generally, the inhibitory activities of both E. faecium and Lactobacillus sp. strains were greater than those of other producer strains. The bacteriocins from the isolates were sensitive to several proteolytic enzymes, and those of L curvatus and L mesenteroides subsp. mesenteroides were also sensitive to lipase and $\alpha$-amylase as well as to proteolytic enzymes. The bacteriocins from the strains of Lactobacillus sp. and a strain of L. brevis were resistant to autoclaving.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.302-307
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• 1995

Four strains of lactic acid bacteria which produced bacteriocins inhibitory to Listeria species were isolated from Kimchi, and were identified as Leuconostoc mesenteroides subsp. mesenteroides (2 strains), Leuconostoc paramesenteroides and Pediococcus pentosaceus. The bacteriocins produced by the isolates inhibited all of the Listeria monocytogenes strains tested, but L. denigrificans 28 and L. welchimeri 89 were not inhibited by the bacteriocin produced by the Leu. paramesenteroides isolate. The bacteriocin produced by the P. pentosaceus isolate was more inhibitory against sensitive strains and showed broader spectrum of antimicrobial activity than those produced by other isolates. The bacteriocins produced by Leuconostoc isolates were sensitive to pronase E treatment, but that produced by the P. pentosaceus isolate was not completely inactivated. The bacteriocins produced by all of the isolates were not sensitive to catalase, ${\alpha}$-amylase and lysozyme and heat (30 min at $100^{\circ}C$) treatments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1228-1236
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• 1997

Lactobacillus strains were isolated from volunteer's feces, including from newly-born infants and adults in their 20's, by using differential MRS-BPB plates. Total 56 presumptive Lactobacillus strains were isolated and the bacteriocin productions by the isolates were examined by agar diffusion method. Six bacteriocin-producing strains were confirmed. Among them, two isolates, HU-1 and H22-3, showed the most outstanding antimicrobial activities, which were not affected by pH adjustments or catalase treatments of culture. HU-1 was originated from a two-years old boy and H22-3 was originated from a newly-born infant. HU-1 and H22-3 had the same morphology(short rod) when examined by scanning electron microscope, and the same biochemical traits including growth temperature range, salt tolerance and sugar-fermenting abilities. But the growth-inhibition spectrum and plasmid profiles of HU-1 and H22-3 were different. Both strains inhibited the growth of various Gram (+) microorganisms including Listeria monocytogenes. Micrococcus luteus, and Staphylococcus aureus in addition to many species of lactic acid bacteria, indicating the production of broad-spectrum bacteriocins. Bacteriocins produced by HU-1 and H22-3 were stable up to 90℃, 15 min heat treatments. Their activities were not affected by pepsin or trypsin treatments but destroyed by proteinaseK or pronase treatments.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.237-251
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• 2020

Lactic acid bacteria prevent the contamination of food products by inhibiting proliferation of pathogenic bacteria. This is done mainly by the production of lactic acid and antimicrobial peptides (AMP_S) known as bacteriocins. The interest in these molecules resides in both their antimicrobial spectrum and safety for human health. The application of bacteriocins or producer strains has been considered to avoid the development of pathogenic bacteria, as most bacteriocins have significant inhibitory activity against food pathogens, such as Listeria monocytogenes. This article describes the classification, structure, mode of action, biosynthesis, and main applications of bacteriocins in different fields: agri-food, aquaculture, and medicine.