• KSBB Journal
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• v.30 no.5
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• pp.245-252
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• 2015

The aim of this study was to investigate the efficacy of enhanced physiological activities in cultures isolated from Korean fermented watery Kimchi, Dongchimi, of single lactic acid bacteria (LAB), and when these three are mixed LAB as probiotics. Using the BIOLOG system and 16S rRNA sequencing, the isolates were characterized, and identified and assigned to Leuconostoc mesenteroides DK-3, Leuconostoc dextranicum DK-6, and Lactobacillus curvatus DK-13, respectively. Growth rate and pH changes, production of organic acids as metabolites, and physiological activities of the single and mixed LAB cultures, were monitored and compared. In mixed LAB cultures after 72 h of incubation, the maximum concentrations of lactic acid and acetic acid were approximately 340.5 mM and 191.9 mM, respectively, and pH changed from 7.00 to 3.62. Mixed LAB cultures were able to eliminate 96.3% of nitrite. Activities of antioxidant and ${\beta}$-galactosidase were 60.3% and 16.8 units/mg, respectively. Significant antibacterial activity of the concentrated supernatants was demonstrated against several food-poisoning bacteria. Physiological activities obtained from the mixed LAB cultures have been shown to be considerably higher than those of single LAB cultures. In conclusion, these studies demonstrate that compared to the single cultures, all physiological activities in mixed LAB cultures are significantly enhanced.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.212-221
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• 2008

This study was performed in an effort to create a functional and stable yogurt product containing slander glasswort extract. The extract was added to milk at concentrations of 0.25, 0.5, and 1.0% (w/v), which was then fermented with lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) at $42^{\circ}C$ for 6 hr. During a period of 15 days of storage, the quality characteristics of the yogurt samples were evaluated in terms of acid production (pH and titratable acidity), levels of lactic acid bacteria, color values, viscosity, and sensory characteristics. There were no significant differences in pH during the storage period; however, the control yogurt presented the highest pH value. The 1.0% slander glasswort yogurt had the highest titratable acidity; but again, there were no significant differences among the yogurts. The 1.0% slander glasswort yogurt also had the highest level of lactic acid bacteria, and both the control and slander glasswort-containing yogurts had increasing levels of lactic acid bacteria over the storage period. The 1.0% slander glasswort yogurt had the lowest L-value and highest a- and b-values. And the slander glasswort yogurts presented lower viscosity values than the control. In sensory evaluations, the 0.25% slander glasswort yogurt scored higher than the other groups for color, flavor, viscosity, sweetness, sourness, and overall palatability. The final sensory results indicated that the 0.25% slander glasswort yogurt was superior.

• Animal Bioscience
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• v.37 no.1
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• pp.84-94
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• 2024

Objective: The objective of this study was to investigate how cellulase or/and lactic acid bacteria (LAB) affected the fermentation characteristic and microbial community in wet brewer's grains (WBG) and corn stover (CS) mixed silage. Methods: The WBG was mixed thoroughly with the CS at 7:3 (w/w). Four treatment groups were studied: i) CON, no additives; ii) CEL, added cellulase (120 U/g fresh matter [FM]), iii) LAB, added LAB (2×10⁶ cfu/g FM), and iv) CLA, added cellulase (120 U/g FM) and LAB (2×10⁶ cfu/g FM). Results: All additive-treated groups showed higher fermentation quality over the 30 d ensiling period. As these groups exhibited higher (p<0.05) LAB counts and lactic acid (LA) content, along with lower pH value and ammonia-nitrogen (NH₃-N) content than the control. Specifically, cellulase-treated groups (CEL and CLA) showed lower (p<0.05) neutral detergent fiber and acid detergent fiber contents than other groups. All additives increased the abundance of beneficial bacteria (Firmicutes, Lactiplantibacillus, and Limosilactobacillus) while they decreased abundance of Proteobacteria and microbial diversity as well. Conclusion: The combined application of cellulase and LAB could effectively improve the fermentation quality and microbial community of the WBG and CS mixed silage.

• Food Science of Animal Resources
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• v.24 no.4
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• pp.416-423
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• 2004

This experiment was carried out to investigate the effect of loquat (Eriobotrya japonica Lindley) extract on the acid production and growth of lactic culture in reconstituted skim milk. The supplementation level of loquat extract to reconstituted skim milk was 10％, 15％ and 20％. Reconstitued skim milk containing loquat extract was fermented by single of mixed culture of Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus casei. General compositions of loquat extract, changes of viable cell count, pH and titratable acidity during fermentation were determined. Chemical compositions of loquat extract were 91.5％ moisture, 0.2％ crude ash, 8.6$^{\circ}$ Brix soluble sugar, 0.34％ total acid, and 4.11 in pH. Supplementation of loquat extract stimulated acid roduction and growth of lactic acid bacteria. Among supplementation levels, a group that was fermented by a single culture of Str. thermophilus with 10％ loquat extract was shown the highest viable cell count (2.10${\times}$10$\^$9/ CFU/mL) at 12 hours after inoculation. When loquat extract was added to reconstituted skim milk at the level of 10％, all mixed cultures of lactic acid bacteria showed higher acid production and the number of viable cell count than 3 kinds of single cultures. Especially, the growth of mixed culture of Str. thermophilus and Lac. acidophilus was promoted by the addition of 10％ loquat extract. Therefore, it was suggested to manufacture the yoghurt with the addition of 10％ loquat extract and the inoculation of mixed culture of Str. thermophilus and Lac. acidophilus for on the stimulation of growth of the lactic culture.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.90-95
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• 2005

Lactic acid bacteria were isolated from silage, which produce high level of hydrogen peroxide in cell culture supernatant. The 16S rDNA sequences of the isolate matched perfectly with that of Lactobacillus fermentum (99.9%), examined by a 16S rDNA gene sequence analysis and similarity search using the GenBank database, thus named L. fermentum CS12-1. L. fermentum CS12-1 showed resistance to low pH and bile acid. The production of hydrogen peroxide by L. fermentum CS12-1 was confirmed by catalase treatment and high-performance liquid chromatography. L. fermentum CS12-1 accumulated hydrogen peroxide in culture broth as cells grew, and the highest concentration of hydrogen peroxide reached 3.5 mM at the late stationary growth phase. The cell-free supernatant of L. fermentum CS12-1 both before and after neutralization inhibited the growth of enterotoxigenic Escherichia coli K88 that causes diarrhea in piglets.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.113-125
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• 2018

Purpose of the present study was to investigate the factors affecting the production of antibacterial substances and histamine in rennet curd prepared by inoculation of histamine-producing lactic acid bacteria (LAB) and probiotic LAB. Probiotic Lactobacillus sakei PIL52 and Lactobacillus plantarum FIL20 produced strong antimicrobial agents against histamine-producing bacteria Lactobacillus brevis LAS129, Enterococcus faecium SBP12, and Enterococcus faecalis SBP58. The lactic acid and crude bacteriocin produced from the probiotic LAB inhibited histamine-producing bacteria in a concentration-dependent manner. As the number of probiotic LAB inoculated for the production of rennet curd increased, the antibacterial activity against histamine-producing bacteria was elevated due to the increased amount of lactic acid and crude bacteriocin in the sample. The growth of probiotic LAB as well as histamine-producing bacteria was inhibited by addition of 10% NaCl, thus the antibacterial substances and histamine contents in rennet curd were significantly lower than those of the control (P < 0.05). Meanwhile, the histamine content was not significantly increased when the rennet curd prepared by mixing probiotic LAB and histamine-producing bacteria was stored at $25^{\circ}C$ for 5 days. However, the amount of histamine detected in the rennet curd was significantly (P < 0.05) increased because the antibacterial activity of the bacteriocin produced by the probiotic LAB was decreased at $20^{\circ}C$ for 20 days.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1035-1045
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• 2016

To evaluate the effects of lactic acid bacteria (LAB) on Peyer's patch cells, mice were treated with a high dose of kanamycin to disturb the gut microbial environment. The overarching goal was to explore the potential of LAB for use as a dietary probiotic that buffers the negative consequences of antibiotic treatment. In vitro, LAB stimulated the production of immunoglobulin A (IgA) from isolated Peyer's patch cells. Inflammation-related genes (TNF-α, IL-1β, and IL-8) were up-regulated in Caco-2 cells stimulated with lipopolysaccharide (LPS), while tight-junction-related genes (ZO-1 and occludin) were down-regulated; the effects of LPS on inflammatory gene and tight-junction gene expression were reversed by treatment with LAB. Mice treated with a high dose of kanamycin showed increased serum IgE levels and decreases in serum IgA and fecal IgA levels; the number of Peyer's patch cells decreased with kanamycin treatment. However, subsequent LAB treatment was effective in reducing the serum IgE level and recovering the serum IgA and fecal IgA levels, as well as the number of Peyer's patch cells. In addition, ZO-1 and occludin mRNA levels were up-regulated in the ileum tissues of mice receiving LAB treatment. Lactic acid bacteria can enhance the intestinal immune system by improving the integrity of the intestinal barrier and increasing the production of IgA in Peyer's patches. Lactic acid bacteria should be considered a potential probiotic candidate for improving intestinal immunity, particularly in mitigating the negative consequences of antibiotic use.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.288-299
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• 2015

Lactobacillus brevis BK11 obtained from Baikkimchi was selected to study the effects of culture medium, initial pH, atmosphere composition, incubation temperature and time, and prebiotics on growth and production of antimicrobial substances. Growth and antimicrobial substances production of L. brevis BK11 were significantly higher in MRS broth than in BHI or M17 broth. The production of cell mass, lactic acid, and bacteriocin by BK11 strain was at maximum in MRS broth adjusted to pH 6.0. Aerobic and microaerobic conditions were favored cell growth and antimicrobial substances production than anaerobic condition. Biomass and lactic acid production and antimicrobial substances activity of BK 11 were significantly better at 30 and $37^{\circ}C$ than at $25^{\circ}C$. Growth of the strain BK11 entered the stationary growth stage at 24 h after inoculation, and decreased after 36 h. Antimicrobial activities of cell-free culture supernatant and bacteriocin solution were highest when cultured in MRS broth with an initial pH 6.0 for 24-30 h at $37^{\circ}C$. In addition, the highest cell number and lactic acid and bacteriocin production were recorded in the presence of 1 and 2% (w/v) fructooligosaccharide (FOS), however, inulin and raffinose did not affect biological and physicochemical characteristics and antimicrobial activities of L. brevis BK11 cultures. According to these results, production of antimicrobial substances by L. brevis KB11 was closely associated with cell density. Under optimal conditions for antimicrobial substances production, L. brevis BK11 effectively inhibited the growth of Helicobacter pylori ATCC 43504.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.531-536
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• 1999

This study was conducted to compare the effects of lactic acid bacteria (LAB) or LAB+cellulases on the cell wall compositions and the in vitro dry matter digestibility (IVDMD) of Rhodesgrass (RG) and Italian ryegrass (IRG) silages. LAB (Lactobacillus cassei) at a concentration of $10{\times}10^5\;cfu.g^{-1}$ fresh forage was added to all ensiling samples (except the untreated control) of RG and IRG. The cellulases used were Acremoniumcellulase (A), Meicelase (M) or a mixture of both (AM). Each cellulase was applied at levels of 0.005, 0.01 and 0.02 % fresh sample. The samples were incubated at 20, 30 and $40^{\circ}C$ for about 2 months of storage. LAB inoculation did not affect cell wall components or IVDMD of both the RG and IRG silages, but LAB+cellulase treatments did. Increasing the amount of cellulase addition resulted in further decreases of cell wall concentrations. This reduction more markedly occurred with cellulases A and AM than it did with cellulase M. Cell wall components losses were higher in the IRG silages than in the RG silages. LAB+cellulase treatments decreased IVDMD of the RG silages, but had no effect on the IRG silages. The different effect of LAB+cellulase treatments on cell wall degradation and IVDMD of the RG and IRG silages suggested that RG contains more structural carbohydrates, which were difficult to degrade with cellulase, than did IRG.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.423-429
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• 2009

The objective of this study was to investigate the potential of the application of lactic acid bacteria (LAB) from kimchi as a starter culture in the production of fermented sausages. To achieve this, a submerged model medium that contained LAB as part of a complex system of kimchi (0.5, 1.0, 1.0, 3.0, and 5.0%) and lyophilized kimchi powder (0.2 and 0.5%) was fermented for 120 h. During the fermentation period, the growth of total viable organisms and LAB, and the changes in the pH and the titratable acidity, were investigated. The initial LAB counts ranged from 6.4 to 7.7 Log CFU/mL for the kimchi media, and from 6.9 to 6.9 Log CFU/mL for the kimchi powder media. In all the kimchi batches, the LAB increased logarithmically, and the highest LAB counts (around 9 Log CFU/mL) were reached in 24 h. An evident lag phase of the LAB was observed in the kimchi powder samples and reached 8.8 Log CFU/mL in 8 h. The decrease in the pH and the formation of lactic acid were rapid in the kimchi batches, and reached pH values of 3.4-3.5 in 12 h. With these results, the LAB that was integrated with the addition of kimchi or kimchi powder demonstrated its potential utility as a substitute for starter culture.