• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.681-687
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• 2007

This study was designed to examine the suitable characteristics of potential probiotic bacteria. Possible probiotic bacteria, including Lactobacillus acidophilus DDS-1, Lb. acidophilus B-3208, Bifidobacterium bifidum KCTC 3357, Lb. plantarum, Leuconostoc mesenteroides ssp. mesenteroides ATCC 8293, and Lactococcus lactis ssp. lactis ATCC 7962 were selected. We then measured their acid and bile tolerances, adhesion properties in the gastrointestinal tract, antimicrobial activity against pathogenic bacteria, and immunomodulation activity. The acid tolerances of Lb. acidophilus DDS-1, Lb. acidophilus B-3208, Lb. plantarum, and Leu. mesenteroides ssp. mesenteroides ATCC 8293, in PBS (pH 2.5) for 2 hr, were high enough that 50% of the inocula survived. The bile tolerances of all bacteria, except Lc. lactis ssp. lactis ATCC 7962, were also observed at a 3% oxgall concentration in MRS broth. The results of the adhesion property assay showed that the total binding affinities of Lb. acidophilus DDS-1, Lb. acidophilus B-3208, and B. bifidum were about three times higher than those of the other bacteria. In testing their antimicrobial activities against pathogens, Lb. acidophilus B-3208, B. bifidum KCTC 3357, and Lb. plantarum inhibited the growth of pathogenic bacteria. For their immunomodulation activity, the cell wall fractions from Lb. acidophilus DDS-1 and Lb. acidophilus B-3208 showed the highest bone marrow cell proliferation activities. However, the cell wall fractions of Lb. acidophilus DDS-1 and B. bifidum, and the cytosol fraction of Lc. lactis ssp. lactis ATCC 7962 showed higher macrophage stimulation activities than those of the other bacteria. Since Lb. acidophilus DDS-1 and Lb. acidophilus B-3208 satisfy the requirements for probiotics, they can be considered suitable probiotic bacteria.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.75-80
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• 2002

The growth inhibition by nisin-Producing lactococci against Bacillus subtilis and its application to doenjang fermentation were investigated. Lactococcus lactis subsp. lactis IFO 12007, L. lactis subsp. lactis ATCC 7962 and L. lactis subsp. lactis ATCC 11454 were used as nisin-producing lactococci. All of three strain rapidly proliferated to more than 10$^{9}$ CFU/g in steamed soybeans. Only L. lactis subsp. lactis IFO 12007 was in steamed soybean without any pH decrease. In spite of the mild decrease in pH, the growth of B. subtilis was completely inhibited; no living cells were detected in a soybean sample inoculated with 10$^{6}$ CFU/g and incubated for 24 to 72h. The L. lactis subsp. lactis IFO 12007 was applied to doenjang fermentation as a starter culture. It produced high nisin activity in steamed soybean, resulting in the complete growth inhibition of B. subtilis, which had been inoculated at the beginning of the meju fermentation, throughout the process of doenjang production. Over-acidification, which is undesirable for doenjang quality, was successfully prevented simply by adding salt which killed the salt-intolerant L. lactis subsp. lactis IFO 12007. Furthermore, the nisin activity in doenjang disappeared with aging.

• Food Science of Animal Resources
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• v.29 no.5
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• pp.640-646
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• 2009

Lactic acid bacteria (LAB) are typical probiotic microbes that are used in various industries including fermented foods, feed additives, and pharmaceuticals. The purpose of this study was to compare the ability of isoflavone biotransformation and antioxidative activity of 17 LAB. Six strains including the Lactobacillus species exhibited a 100% hydrolysis rate for daidzein during fermentation. The content of total genistein in soymilk fermented with these strains was $872-943\;{\mu}g/g$. The DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging ability of the LAB was widely variable and ranged from 23-78%. A selected strain was isolated from kimchi and the strain was identified as Lactobacillus plantarum ssp. through the API carbohydrate fermentation pattern and 16S rDNA profile. The strain exhibited excellent acid tolerance in an artificial gastric solution. L. plantarum YS712 showed high $\beta$-glucosidase activity in fermentation. The concentration of genistein and daidzein in soymilk fermented with L. plantarum YS712 increased from 3.64 to $917.3\;{\mu}g/g$ and from 58.18 to $1062.17\;{\mu}g/g$, respectively. These results demonstrate the potential of L. plantarum YS712 as a probiotic culture that can be utilized in the manufacturing of fermentation foods and dietary supplements.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.829-835
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• 2000

The ptsH and ptsI genes of Lactococus lactis subsp. lactis ATCC 7962 (L. lactis 7962), encoding the general proteins of phosphotransferase system (PTS) components, HPr and enzyme I, respectively, were cloned and characterized. A 1.3 kb PCR product was obtained using a primer set that was hybridized to the internal region of the L. lactis 7962 pts HI genes and then subcloned into a low-copy number vector, pACYC184. The 5' upstream and 3' downstream region from the 1.3 kb fragment were subsequently clone using the chromosome walking method. The complete ptsHI operon was constructed and the nucleotide sequences determined. Two ORFs corresponding to HPr (88 amino acids) and enzyme I (575 amino acids) were located. The ptsHI genes of L. lactis 7962 showed a very high homology (84-90%) with those genes from other Gram-positive bacteria. A primer extension analysis showed that the transcription started at either one of two adjacent bases upstream of the start codon. Using a Northern analysis, two transcripts were detected; the first, a 0.3 kb transcript corresponding to ptsH and the second, a 2 kb transcript corresponding to ptsH and ptsI. The transcription level of ptsH was higher than that of ptsI. The concentration of the ptsH transcript in cells grown on glucose was similar to that in cells grown on lactose, yet higher than that in cells grown on galactose. The ptsI transcript was scarcely detected in cell grown on lactose or galactose. The ptsI transcript was scarcely detected in cells grown on lactose or galactose. The results of a sequence analysis and Northern blot confirmed that the ptsH and ptsI genes of L. lactis 7962 were arranged in an operon like other known ptsHI genes and the expression of the ptsHI genes was regulated at the transcriptional level in response to the carbon source.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.348-354
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• 2003

This study was conducted to confirm the availability of lactic acid bacteria as probiotics haying inhibitory effects to cancer cell line. Five lactic acid bacteria showing anti-cancer activity were compared by acid tolerance, bile tolerance, antibiotics resistance, milk fermentation, stability, and cell adherence activity to colon epithelial cell. The results obtained are as follows : In acid tolerance, all strains did not have a resistance below pH 3.0 and 3.5 except Lactobacillus plantarum KCTC3099. In antibiotics resistance, Lactococcus lactis and L. plantarum KCTC3099 were resistant to cotrimoxazol (128 mg/1), and Bifidobacterium adolescentis Maeil-K8 and B. infantis Maeil-K9 were resistant to doxycylin and gentamycin (4 mg/1). In case of cell adherence ability to Caco-2 cell, B. infantis Maeil-K9 was found to be superior to others as 3.1%, while the others were less than 0.5%. When the strains were cultured to milk base, viable counts of the strains tested increased more 1 log cycle than inoculation, but acid production was very low except L. plantarum KCTC3099. Also, L. plantarum KCTC3099, B. adolescentis Maeil-K8, and B. infantis Maeil-K9 were stable in fermented milk base during storage. In conclusion, L. plantarum KCTC3099 and B. infantis Maeil-K9 were confirmed to be superior for the availability as probiotics.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.1
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• pp.48-54
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• 2007

Bacillus polyfermenticus SCD (B. polyfermenticus SCD) has been appropriately used for the therapy of long-term intestinal disorders, because live strains in the form of active endospores can successfully reach the target intestine in humans. B. polyfermenticus SCD produces the most antibiotic-related materials. In the present study, B. polyfermenticus SCD was fermented with soybeans (BPFS) and its probiotic properties were investigated. B. polyfermenticus SCD and BPFS showed a broad spectrum of antimicrobial activity against pathogenic Gram-positive (Streptococcus parauberis, Streptococcus iniae, Lactococcus garviae) and Gram-negative (Flexibacter tractuosus, Vibrio harveyi, Vibrio vulnificus, Vibrio ordalii) bacteria and moulds (Aspergillus niger, Aspergillus oryzae). Sebastes schlegeli were used to examine survival rate and cleanup action by BPFS. Bacterial infection resulted in a mortality of up to 99% in the commercial fodder fed groups. BPFS both enhanced the growth rate of fry by improving their appetite and had cleaned by decreased eutrophication. Therefore, it seems appropriate that BPFS should be developed as an antibiotic replacement, favorable fodder additive, and antifungal material in fish farming systems.

• Journal of Dairy Science and Biotechnology
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• v.38 no.2
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• pp.70-88
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• 2020

Lactic acid bacteria (LAB) form an essential part of the intestinal microbiota of the human body and possess the ability to stabilize the intestinal microbiota, strengthen immunity, and promote digestion as well as intestinal synthesis of vitamins, amino acids, and proteins. Hence, LAB are currently widely used in various products. However, due to the indiscriminate overuse of antibiotics in humans and livestock, bacterial resistance to antibiotics has been increasing rapidly, which has led to serious problems in the treatment of bacterial infections. Additionally, several reports have revealed that antibiotic-resistant LAB may infect people whose immune systems are not fully developed or whose immune systems are temporarily weakened. Therefore, it is imperative to consider the possibility of antibiotic-resistant LAB causing diseases in humans and animals, investigate the mechanism of action between antibiotics and LAB, and determine the relevant regulations for the safe use of LAB.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1464-1473
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• 2018

Objective: To describe in-depth sequencing, the bacterial community diversity and its succession during ensiling of whole-plant maize and subsequent exposure to air. Methods: The microbial community dynamics of fermented whole-plant maize for 60 days (sampled on day 5, 10, 20, 40, 60) and subsequent aerobic exposure (sampled on day 63 after exposure to air for 3 days) were explored using Illumina Miseq sequence platform. Results: A total of 227,220 effective reads were obtained. At the genus level, there were 12 genera with relative abundance >1%, Lactobacillus, Klebsiella, Sporolactobacillus, Norank-c-cyanobacteria, Pantoea, Pediococcus, Rahnella, Sphingomonas, Serratia, Chryseobacterium, Sphingobacterium, and Lactococcus. Lactobacillus consistently dominated the bacterial communities with relative abundance from 49.56% to 64.17% during the ensiling process. Klebsiella was also an important succession bacterium with a decrease tendency from 15.20% to 6.41% during the ensiling process. The genus Sporolactobacillus appeared in late-ensiling stages with 7.70% abundance on day 40 and 5.32% on day 60. After aerobic exposure, the Lactobacillus decreased its abundance from 63.2% on day 60 to 45.03% on d 63, and Klebsiella from 5.51% to 5.64%, while Sporolactobacillus greatly increased its abundance to 28.15%. These bacterial genera belong to 5 phyla: Firmicutes (relative abundance: 56.38% to 78.43%) was dominant, others were Proteobacteria, Bacteroidetes, Cyanobacteria, and Actinobacteria. The bacterial communities clearly clustered into early-ensiling (d 5), medium-ensiling (d 10, d 20), late-ensiling (d 40, d 60), and aerobic exposure (d 63) clusters, with early- and late-ensiling communities more like each other than to the aerobic exposure communities. Conclusion: High-throughput sequencing based on 16S rRNA genes proved to be a useful method to explore bacterial communities of silage. The results indicated that the bacterial communities varied during fermentation and more dramatically during aerobic exposure. The study is valuable for understanding the mechanism of population change and the relationship between bacteria and ensilage characteristics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.2
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• pp.328-332
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• 2014

A survey was conducted on the isolation of lactic acid bacteria with antibacterial activity to extend kimchi shelf-life. Antibacterial activity was tested against bacteria associated with acidification of kimchi, including Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus sakei, using agar-well diffusion assay. Two isolates from kimchi were identified as Lactococcus lactis subsp. lactis and Lactobacillus brevis by 16S rRNA gene sequence analysis and API 50 CHL assay, and they showed antibacterial effects against indicator strains. The isolates displayed acid tolerance at pH 3.5, salt tolerance in 5% NaCl, and growth at $4^{\circ}C$. These result imply that the selected strains might be used to extend kimchi shelf-life as a potential starter.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1717-1725
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• 2013

Traditional soybean paste from Shandong Liangshan and Tianyuan Jiangyuan commercial soybean paste were chosen for analysis and comparison of their bacterial and fungal dynamics using denaturing gel gradient electrophoresis and 16S rRNA gene clone libraries. The bacterial diversity results showed that more than 20 types of bacteria were present in traditional Shandong soybean paste during its fermentation process, whereas only six types of bacteria were present in the commercial soybean paste. The predominant bacteria in the Shandong soybean paste were most closely related to Leuconostoc spp., an uncultured bacterium, Lactococcus lactis, Bacillus licheniformis, Bacillus spp., and Citrobacter freundii. The predominant bacteria in the Tianyuan Jiangyuan soybean paste were most closely related to an uncultured bacterium, Bacillus licheniformis, and an uncultured Leuconostoc spp. The fungal diversity results showed that 10 types of fungi were present in the Shandong soybean paste during the fermentation process, with the predominant fungi being most closely related to Geotrichum spp., an uncultured fungal clone, Aspergillus oryzae, and yeast species. The predominant fungus in the commercial soybean paste was Aspergillus oryzae.