• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.215-220
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• 1990

Prophage cured strain derivatives from Luctobacillirs araei YIT 9018 were isolated from thermoinducible mutant of the parent lysogenic strain. Two thermoinducible mutants were isolated from L. casei YIT 9018 strain treated with N-methyl-N'-nitro-N-nitrosoguanidine. Prophage cured strains were selected after heat induction of thermoinducible strains at $42^{\circ}C$ for 30 min in MRT medium containing anti- 4 FSV serum. The prophage cured strains, L. casei HYM 1213 and L. casei HYM 4024, could be used an indicator strain for temperate phage $\phi$ FSW. The growth, lactic acid producing ability and carbohydrates fermentation of L. casei HYM 1213 were similar to the parent L. cmei YIT 9018 strain, but A. casei HYM 4024 was not. One of the prophage cured strain, L. cmei HYM 1213, could be used industrially .to produce lactic acid beverages because this strah could not induce the virulent phage$\phi$FSV. The physiological characterization of L. casei HYM 1213 strain was similar to the parent L. casei YIT 9018 strain.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.95-99
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• 1995

The distribution of lactic acid bacteria and total bacteria in 27 samples of Nuruk (traditional Korean rice wine starter) were investigated, and lactic acid bacteria isolated from those samples were identified. The average number of lactic acid bacteria and total bacteria were $2,11{\times}10^7$ and $2.08{\times}10^8\;cfu/g$, respectively. There was no appreciable differences in the number of lactic acid bacteria among those samples, meanwhile the number of total bacteria varied significantly from sample to sample. Among the lactic acid bacteria, more cocci were counted than rods in those samples. Thirty-two strains of lactic acid bacteria obtained from those samples were identified as Leuconostoc mesenteroides subsp. mesenteroides (11 strains), Pediococcus acidilactici (7 strains), Lactobacillus plantarum (3 strains), L. murinus (7 strains) and Enterococcus faecium (4 strains).

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.1-6
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• 2004

Tetracycline resistant bacterial strains were isolated from 10 batches of Kimchi among 50 batches collected in Taegu restrict. The MIC of tetracycline ranged between 25 and> 100 ㎖/l. Total genomic DNA preparation from all 10 tetracycline resistant lactic acid bacterial isolates were subjected to PCR amplification with class-specific primers for tet(M) and tet(O). In only one isolate, HJ9, tet(M) was detected. By Southern blotting and hybridization with a tet(M)-specific probe, the tet(M) gene of HJ9 isolate could be localized on a plasmid. The partial nucleotide sequence and deduced amino acid sequence of tet(M) of HJ9 showed 90-99% and 94-100% homology to those of Gram positive bacteria, respectively. With sequencing of 16S rRNA, HJ9 isolate from Kimchi was identified as Lactobacillus sakei. From these results, Kimchi can be considered potential vehicle for the spread of antibiotic-resistant lactic acid bacteria along the food chain to the consumer.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.621-632
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• 2007

The aim of this study was to isolate and characterize bacteriocin-producing bacteria from the intestine of duck to use as probiotics for livestock. A total of 416 strains were isolated from the small intestine and cecum of ducks and 13 isolates were finally selected after determinging inhibitory activity against pathogenic indicators by spot-on-lawn method. The selected strains were identified as Lactobacillus salivarius JWS 58, Lactobacillus plantarum JWS 1354, Pediococcus pentosaceus JWS 939, 7 strains of enterococci, and 3 strains of Escherichia coli. Lact. salivarius JWS 58, Ent. faecium JWS 833, and Ped. pentosaceus JWS 939 showed a strong inhibitory activity against Listeria monocytogenes. E. coli JWS 108 inhibited the growth of E. coli and Staphylococcus aureus. Lact. salivarius JWS 58 strain survived almost 50% in pH 2.5 phosphate buffer for 2 hr. Ped. pentosaceus JWS 939 and Lact. plantarum JWS 1354 showed strong amylolytic activity. These results suggest that a combination of bacteriocins or multispecies probiotics of the selected strains has a strong potential of alternative to antibiotics in livestock production.

• Journal of Life Science
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• v.28 no.1
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• pp.68-77
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• 2018

The purpose of this study was to isolate the probiotic lactic acid bacteria, and verify the possibility of the final selection strain as probiotic material. For screening of biogenic amines non-producing microorganisms, 42 lactic acid bacteria were isolated from various berries, extract and vinegar grown in Sunchang. Isolates were investigated for various physiological activities such as extracellular enzyme, antimicrobial and antioxidant activities, and 5 isolates were firstly screened. SBB07 was finally selected by analyzing the biogenic amine, and named Lactobacillus brevis SBB07 by 16S rRNA sequencing analysis. Next, SBB07 was assayed for their survival ability when exposed to acidic and bile conditions as well as heat and antibiotic resistance. As a result, SBB07 showed more than 86% and 54% higher survival rate in acidic condition at pH 2.0 and bile resistance with 0.5% oxgall. In addition, SBB07 showed a survival rate of more than 113% in $60^{\circ}C$, and also confirmed that it has resistant to various antibiotics. As a result of confirming the possibility of prebiotics, SBB07 showed the best utilization of GOS as a prebiotic substrate, and utilization of FOS and inulin were also high. These results suggest that SBB07 have good potential for application as probiotic lactic acid bacteria.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.26-31
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• 2009

This study was aimed at the analysis of prokaryote communities in Korean traditional fermented food, jeotgal, and isolation of a novel strain from jeotgal by using culture-dependent and molecular biological approaches. Seventeen kinds of jeotgal were selected on the basis of its origins and sources. The samples were inoculated on 12 kinds of media. 308 isolates were selected randomly by morphological features, and its 16S rRNA gene sequences was amplified by PCR technique with bacteria and archaea specific primers (8F, 21F, and 1492R). The 16S rRNA gene sequences were compared with those in EzTaxon and GenBank databases. DNA-DNA hybridization was performed to identify a novel strain. As a result, the majority of the isolates were lactic acid bacteria (Leuconostoc, Weisella, Lactococcus, Lactobacillus, Carnobacterium, Marinilactibacillus), Bacillus, Pseudomonas, Micrococcus, Brevibacterium, Microbacterium and Kocuria in 17 kinds of jeotgal. The strains belonging to Salinicoccus, Halomonas, Cobetia, Lentibacillus, Paracoccus, and Psychrobacter were isolated as minor ones. Fourteen novel species were identified based on phylogenetic analysis.

• Journal of Dairy Science and Biotechnology
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• v.42 no.1
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• pp.9-17
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• 2024

This study aimed to evaluate the appropriateness of MRS-C (0.05% L-cystein; pH 5) and BHI-CM (0.05% L-cystein, 0.5% mucin) agars for the selective isolation of bifidobacteria in fecal samples compared to blood-liver-NPNL (BL-NPNL) agar. Over 200 isolated colonies were characterized morphologically and biochemically. Genomic DNA was extracted from pure cultures of the isolated strains, followed by PCR amplification of the 16S rRNA gene. Bifidobacterium longum and B. animalis were selectively isolated from MRS-C agar and Lactobacillus acidophilus and Enterococcus avium were also isolated. B. longum, B. faecale, and B. animalis were isolated from feces on BHI-CM agar; however, different Bacteroides strains (including Bac. fragilis, Bac. kiribbi, Bac. ovatus, Bac. koreensis, and Bac. salyersiae) were also detected. BL-NPNL agar successfully isolated B. longum and Bacillus, while other Bifidobacterium and Bacteroides species could not grow owing to the presence of antibiotics in the medium. The use of antibiotics in a medium can enhance the selectivity; however, antibiotics may inhibit the growth of certain bacteria in a sample. Hence, adjusting pH or adding non-antibiotic nutrients to the medium is more advantageous, than relying on antibiotics.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.819-827
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• 2017

Objective: Four lactic acid bacteria (LAB) strains isolated from common vetch, tall fescue and perennial ryegrass on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) silage were studied. Methods: The four isolated strains and one commercial inoculant (G, Lactobacillus plantarum MTD-1) were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. The five LAB strains were added to Italian ryegrass for ensiling at three different temperatures ($10^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$). Results: All isolated strains (LCG3, LTG7, I5, and LI3) could grow at $5^{\circ}C$ to $20^{\circ}C$, pH 3.0 to 8.0 and NaCl (3.0%, 6.5%). Strains LCG3, LTG7, I5, and LI3 were identified as Lactobacillus plantarum, Pediococcus acidilactici, Lactobacillus paraplantarum, and Lactobacillus casei by sequencing 16S rDNA, respectively. All LAB inoculants significantly (p<0.05) increased lactic acid (LA) contents and ratios of lactic acid to acetic acid, and reduced pH and ammonia nitrogen/total nitrogen (AN/TN) compared with uninoculated silages at various temperatures ($10^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$). Compared to the commercial inoculant G, I5, and LI3 showed similar effects on improving the silage quality of Italian ryegrass at $10^{\circ}C$ and $15^{\circ}C$, indicated by similar pH, LA content and AN/TN. Conclusion: All inoculants could improve the silage fermentation quality at various temperatures ($10^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$). At the temperature of $10^{\circ}C$ and $15^{\circ}C$, strain I5 and LI3 had similar effects with the commercial inoculant G on improving the silage quality of Italian ryegrass.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.721-726
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• 2012

Lactic acid bacteria (LAB) are able to secrete antimicrobial peptides called bacteriocins, which inhibit other bacteria such as pathogenic microorganisms. Therefore, bacteriocin-producing starters can be used as natural biopreservatives for various foods. The objective of this study was to screen and characterize bacteriocin-producing LAB from Kimchi and to investigate their applicability as a starter in Kimchi fermentation. To screen bacteriocin-producing LAB, gram-positive and gram-negative bacteria were used as indicators. To measure the antimicrobial activities of isolates, agar well diffusion assay method was used. According to the results, bacteriocin produced by $Lb.$ $sakei$ B16 showed antimicrobial activity against $Listeria$ $monocytogenes$ ATCC 19115, $Escherichia$ $coli$ KCTC 1467, and$Lactobacillus$ $plantarum$ KTCT 3104. Furthermore, bacteriocin was very stable after treatment with high temperature and high and low pH, but its effects were inhibited by treatment with proteolytic enzymes such as trypsin, proteinase K, and ${\alpha}$-chymotrypsin, revealing their bacteriocin-like protein- based structure. These results suggest that $Lb.$ $sakei$ B16 and its bacteriocin are good candidates as a functional probiotic and natural biopreservative, respectively, in fermented foods.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1798-1807
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• 2002

This study was conducted to investigate lactobacillus salivarius subsp. salivarius having probiotic properties to be used as the health adjuncts with fermented milk products. Acid- and bile-tolerant lactobacillus salivarius subsp. salivarius was isolated with lactobacilli MRS broth from faeces of 80 healthy persons (infants, children and adults). It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at 37$^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by 0.9-1.0% at 37$^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced 23-38% of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 h at 37$^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with 15-25 mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.