• Food Science of Animal Resources
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• v.30 no.5
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• pp.795-803
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• 2010

A DF01 strain that inhibits tyramine-producing Lactobacillus curvatus KFRI 166 was isolated from Dongchimi, a traditional Korean fermented vegetable, and identified as Lactobacillus brevis by biochemical analysis and reverse transcriptase sequencing of 16S rRNA. The antimicrobial compound produced by L. brevis DF01 was secreted at a maximum level of 640 AU/mL in late exponential phase in MRS broth, and its activity remained constant during stationary phase. The activity of bacteriocin DF01 was totally inactivated by $\alpha$-chymotrypsin, pronase E, proteinase K, trypsin, and $\alpha$-amylase, but not by catalase, which indicates the compound was glycoprotein in nature. The activity was not affected by pH changes ranging from 2 to 12 or heat treatment (60, 80, and $100^{\circ}C$ for 30 min), but was reduced after autoclaving. Bacteriocin DF01 had bacteriolytic activity and a molecular weight of approximately 8.2 kDa, as shown by tricine-SDS-PAGE analysis. Therefore, bacteriocin DF01 can be used in the manufacture of fermented meat products due to its inhibition of tyramine-producing L. curvatus and non-inhibition of L. sake, which is used as a starter culture for meat fermentation.

• Food Science of Animal Resources
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• v.43 no.4
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• pp.625-638
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• 2023

Among various biological agents, bacteriocins are important candidates to control Listeria monocytogenes which is a foodborne pathogen. In this study, a novel bacteriocin, named agilicin C7, was isolated from Ligilactobacillus agilis C7 showing inhibitory activity against L. monocytogenes. Agilicin C7 biosynthesis gene was characterized by bioinformatics analyses and heterologously expressed in Escherichia coli for further study. The anti-listeria activity of recombinant agilicin C7 (r-agilicin C7) was lost by proteases and α-amylase, suggesting that agilicin C7 is a glycoprotein. r-Agilicin C7 has wide pH and thermal stability and is also stable in various organic solvents. It destroyed L. monocytogenes by damaging the integrity of the cell envelope. These properties of r-agilicin C7 indicate that agilicin C7 is a novel amylase-sensitive anti-listerial Class IId bacteriocin. Physicochemical stability and inhibitory activity against L. monocytogenes of r-agilicin C7 suggest that it can be applied to control L. monocytogenes in the food industry, including dairy and meat products.

• 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.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.7-12
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• 1994

One bacterial strain, that had made the largest inhibition zone at the antagonism assay and also that lost the inhibition activity by the protease treatment, was isolated from raw milk. That strain was identified as Streptococcus salivarius subsp. thermophilus. The specific growht rate of this strain was maximum at 45$\circ $C. However, at this temperature the strain produced no bacteriocin. The bacteriocin activity was quite stable even at high temperature. Moreover, the activity of the vacteriocin was sensitive to proteases. but not to $\alpha $-amylase, DNase I, or RNase.

• 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.

• Journal of Life Science
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• v.25 no.2
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• pp.180-188
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• 2015

The bacterial strain isolated from Kimchi showed antibacterial activity against Micrococcus luteus IAM 1056. The selected strain was identified as Lactococcus lactis by 16S rRNA nucleotide sequence analysis and named as Lactococcus sp. KD 28. The treatment of culture supernatant with proteinase K removed antibacterial activity, indicating its proteinaceous nature, a bacteriocin. This bacteriocin was sensitive to hydrolytic enzymes such as ${\alpha}$-chymotrypsion, trypsin, proteinase K, lipase, ${\alpha}$-amylase and subtilisin A. The bacteriocin was highly thermostable and resistant to heating at $80^{\circ}C$ for up to an hour but 50 % of the total activity was remained at $100^{\circ}C$ for 30 min. The pH range from 2.0 to 8.0 had no effect on bacteriocin activity and it was not affected by solvents such as acetonitrile, isopropanol, methanol, chloroform and acetone up to 50% concentration. The bacteriocin showed antibacterial activity against M. luteus IAM 1056, Lactobacillus delbrueckii subsp. lactis KCTC 1058, Enterococcus faecium KCTC 3095, Bacillus cereus KCTC 1013, B. subtilis KCTC 1023, Listeria ivanovii subsp. ivanovii KCTC 3444, Staphylococcus aureus subsp. aureus KCTC 1916, B. megaterium KCTC 1098 and B. sphaericus KCTC 1184. The bacteriocin was purified through ammonium sulfate concentration, SP-Sepharose chromatography and RP-HPLC. The molecular weight was estimated to be about 3.4 kDa by tricine-SDS-PAGE analysis.