• Journal of Dairy Science and Biotechnology
• /
• v.36 no.1
• /
• pp.1-13
• /
• 2018

Kefir exhibits antimicrobial activity in vitro against gram-positive and gram negative bacteria, as well as some fungi. The ability of LAB to inhibit the growth of closely related bacteria is well known. This inhibition of pathogenic and spoilage microbes may be due to the production of organic acids, hydrogen peroxide, acetaldehyde, diacetyl, carbon dioxide, or bacteriocins. Lactobacilli are the major contributors to acid production and, hence, a determining factor in the flavor development in kefir. Lactic acid, proteolytic activity, and acetaldehyde are the essential flavor compounds in kefir. Both acid and bacteriocins contribute to the antimicrobial activity of kefir and kefir grains. Kefir is rich in proteins, calcium, vitamin $B_{12}$, niacin, and folic acid. Many studies have investigated the benefits of consuming kefir and have shown that it is a natural probiotic, which when consumed regularly, can help relieve intestinal disorders, promote bowel movement, reduce flatulence, and improve the overall health of the digestive system. Tibetan kefir, which is different from traditional kefir, is produced in China. It has been reported to exhibit antimicrobial activity that is nearly identical to that of traditional kefir. Kefir production is considered a rapidly growing food industry in China.

• Korean Journal of Microbiology
• /
• v.47 no.3
• /
• pp.231-240
• /
• 2011

The objective of this study was to evaluate the acid and bile tolerance, bile salt hydrolase (BSH) activity, and cholesterol assimilation ability of lactic acid bacteria isolated from mustard leaf kimchi. MLK11, MLK22, MLK27, MLK41, and MLK67 were relatively acid- and bile-tolerant strains, with more than $10^5$ CFU/ml after incubation in simulated gastric juice and intestinal fluid, while MLK53 was the most sensitive strain to acid and bile. Strains MLK22 and MLK67 deconjugated the highest level of sodium glycocholate with more than 3.5 mM of cholic acid released, while deconjugation was lowest by strains MLK13 and MLK41 which released only 1.35 mM and 1.16 mM, respectively. Specially, strains MLK22 and MLK67 showed higher deconjugation of sodium glycocholate compared to sodium taurocholate and conjugated bile mixture. Although strains MLK22 and MLK67 exhibited maximal BSH activity at the stationary phase, MLK22 had somewhat higher total BSH activity compared to MLK67 towards both sodium glycocholate and sodium taurocholate. Meanwhile, cholesterol removal varied among tested strains (p<0.05) and ranged from 5.22 to 39.16 ${\mu}g$/ml. Especially, MLK67 strain assimilated the highest level of cholesterol in media supplemented with 0.3% oxgall, cholic acid, and taurocholic acid (p<0.05). According to physiological and biological characteristics, pattern of carbohydrate fermentation, and 16S rDNA sequence, strain MLK67 that may be considered as probiotic strain due to acid and bile tolerance and cholesterol-lowering effects was identified as Pediococcus pentosaceus MLK67.

• Journal of Life Science
• /
• v.27 no.2
• /
• pp.172-179
• /
• 2017

The fermentation of Panax ginseng can yield many compounds from ginsenosides that have a wide variety of biological functions. Lactic acid bacteria (LAB) strains are capable of converting ginsenosides. The purposes of this study were to: (1) characterize Enterococcus faecium SA5, an isolated LAB from Mongolian mare milk, (2) identify the existence of extracellular ${\beta}$-glucosidase activity in the milk, and (3) ascertain if the ${\beta}$-glucosidase has the capacity of converting ginsenoside in Korean ginseng. The results revealed that E. faecium SA5 was acid-resistant, bile salt-resistant, and has antibiotic activities against 4 pathogenic microorganisms (Salmonella typhimurium KCTC 3216, Listeria monocytogenes KCTC 3710, Bacillus cereus KCTC 1012, Staphylococcus aureus KCTC 1621). In addition, E. faecium SA5 had tolerance against some antibiotics such as colistin, gentamycin and neomycin. It was also found that E. faecium SA5 possessed bile salt hydrolase activity, which could lower blood cholesterol level. When incubated in 10% (w/v) skim milk as a yogurt starter, E. faecium SA5 caused to decrease pH of the medium as well as increase in viable cell counts. Using TLC and HPLC analysis on the samples incubated in MRS broth, our study confirmed that E. faecium SA5 can produce ${\beta}$-glucosidase, which was capable of converting ginsenoside $Rb_1$ into new ginsenosides $Rg_3-s$ and $Rg_3-r$. It was concluded that E. faecium SA5 possessed a potential of probiotic activity, which could be applied to yogurt manufacture as well as ginsenoside conversion in ginseng.

• Journal of Life Science
• /
• v.30 no.7
• /
• pp.581-591
• /
• 2020

This study investigated the probiotic properties and physiological activities of Korean fermented foods such as sikhae, young radish kimchi, and bean-curd dregs. Among the isolated lactic acid bacteria, Pediococcus inopinatus BZ4, Lactobacillus plantarum SH1, Lactobacillus brevis SH14, Pediococcus pentosaceus YMT1, and Leuconostoc mesenteroides YMT6 demonstrated a greater than 60% survival rate at pH 2.5, along with an excellent survival rate even at 0.3% bile acid. These five bacteria showed strong flocculation ability in autoaggregation and coaggregation tests, indirectly clustering useful micro-organisms and inhibiting the attachment of pathogenic bacteria. In a cell surface hydrophobicity test, these bacteria showed adhesion to three solvents (ethyl acetate, chloroform, and xylene) and high hydrophobicity, thereby indicating excellent indirect cell adhesion to intestinal cells. The cell-free supernatants and intracellular extracts of the five lactic acid bacteria showed antioxidative activity in the form of 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging ability and lipid peroxidation inhibition. Antimicrobial activities were also observed in four pathogenic bacteria, namely E. coli KCTC 2571, H. pylori HPKCTC B0150, L. monocytogenes KCTC 13064, and S. aureus KCTC 1916. These results demonstrate that these five lactic acid bacteria could be used as probiotics with antioxidant and antimicrobial properties.

• Microbiology and Biotechnology Letters
• /
• v.39 no.3
• /
• pp.266-273
• /
• 2011

Although turmeric has numerous pharmacological effects, the poor water-solubility of curcuminoids, active components of turmeric, restricts their systemic availability in orally administered formulations and limits their therapeutic potential. In this study we attempted turmeric fermentation using several probiotic bacteria to improve its solubility, and also investigated the effects of turmeric and fermented turmeric on anti-inflammatory activity. Fermented turmeric, by L. johnsonii IDCC 9203, more strongly inhibited LPS-induced expression of the pro-inflammatory cytokines than non-fermented turmeric and fermented turmeric by other probiotic strains. We used an NC/Nga mouse model for mite antigen-induced atopic dermatitis to examine the efficacy of the fermented turmeric. Fermented turmeric-fed mice exhibited a significantly reduced serum IgE level and mitigated acute inflammation. When the fermented turmeric was pre-treated by oral administration, it had more preventive activity against acute anaphylactic reaction than the non-fermented group. In addition, we observed that fermentation of turmeric leads to increased water-solubility of curcumin and a change in the active components ratios for bisdemethoxycurcumin, demethoxycrucumin and curcumin. Taken together, these results strongly suggest that fermented turmeric by L. johnsonii IDCC 9203 could be used as a functional food ingredient for improving treatments for atopic dermatitis.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2094-2103
• /
• 2017

Aging is associated with distinct changes in immune cells and a decline in immune function, leading to increased susceptibility to infection and reduced responses to vaccination. Certain strains of lactic acid bacteria exert beneficial effects on the immune system. Previously, we reported that Weissella cibaria JW15 isolated from kimchi possesses immune stimulatory activity in vitro. In the present study, we further investigated whether oral administration of JW15 improves immune function in aged mice. Eighteen-month-old female mice were administered JW15 daily at low (JW15-L; $1{\times}10^8CFU/mouse$) or high dosage (JW15-H; $1{\times}10^9CFU/mouse$), or with Lactobacillus rhamnosus GG (LGG) using oral gavage. Two-month-old female mice were included as healthy young mice. After 4 weeks, the mice were euthanized and immune profiles were analyzed using whole blood and spleen. In complete blood count analysis, the numbers of white and red blood cells were significantly increased in the JW15-L group compared with those in the old mouse (OM) control group. In addition, administration of either JW15 of LGG resulted in higher numbers of splenocytes in comparison with the OM group. Furthermore, proliferative potentials were higher in all probiotic groups than OM. Cytokines such as IFN-${\gamma}$ and IL-6 were secreted at higher levels in splenocytes isolated from JW15-fed mice than in OM control mice. Similarly, mRNA expression of various cytokines was altered in the JW15 groups. Collectively, these results suggest that JW15 supplementation induces immunomodulatory effects in aged mice and indicate JW15 as a potential probiotic strain to improve immune function in aged animals.

• Food Science of Animal Resources
• /
• v.38 no.1
• /
• pp.88-98
• /
• 2018

In this study, we isolated and characterized a bacteriocin-producing strain and two bacteriophages (P4, A3), showing antimicrobial effects against Clostridium perfringens, from chicken and swine feces by the spot-on-the lawn antagonism method. The selected strain was identified as Streptococcus hyointestinalis by 16S rRNA gene sequencing. The bacteriocin from the isolated strain exhibited strong inhibitory activity against four strains of C. perfringens and all the tested strains of Listeria monocytogenes, and the bacteriocin were highly heat- and pH-stable even at pH 2, pH 10 and $121^{\circ}C$ for 15 min. We also evaluated the combined effects of the isolated bacteriocin and phages. Combining the phage treatments and bacteriocin resulted in a synergetic effect compared with the phage or the bacteriocin alone. In addition, during the probiotic test, the bacteriocin-producing S. hyointestinalis B19 strain reduced the population of C. perfringens significantly. Treatment with S. hyointestinalis B19 and a cocktail of lytic bacteriophages eradicated the C. perfringens KCTC $3269^T$, completely. Consequently, the isolated bacteriocin and bacteriophages represent candidates for effective biocontrol of C. perfringens, and bacteriocin-producing S. hyointestinalis B19 is a potential probiotic candidate for use in domestic animals.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.4
• /
• pp.99-104
• /
• 2001

The influence of agitation speed on the yeast growth was investigated in the production of probiotic feed from pulverized liquified food wastes by aerobic fermentation. A yeast Kluyvermyces marxianus was selected through a preliminary screening. The yeast was cultured by 2liter jar fermenter. in 10% solid(w/v) substrate of liquified food waste at $35^{\circ}C$ with each different agitation speed of 500, 900 and 1200 rpm. For the acceleration of enzyme excretion mixed culture with Aspergillus oryzae was also attempted and the results were compared to those of single culture. As results the viable cell number was increased by increasing agitation speed. But it showed highest value in 900rpm and then decreased in 1200rpm. The mixed culture increased amylase activity and growth rate, but did not seem to enhance the highest viable cell count in the final fermentation stage.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.3
• /
• pp.126-131
• /
• 2002

For the probiotic feed production from residual food waste, aerobic liquid fermentation was conducted by thermophilic bacteria. 11 Strains of bacteria were isolated from several soil sources and residual food waste. Screening was carried by shaking incubator for the separation of thermophilic strain at $55^{\circ}C$. The isolated strains were tested for enzyme activities such as ${\alpha}$-amylase and protease. 6 Bacterial strains were chosen and were adapted by repeated fermentation processes in food waste substrate. The viable cell count of them at final fermentation stages were shown as $3-7{\times}10^9/ml$ in 2L-jar fermenter. Among them B3, B6 showed higher enzyme activity. By the mixed fermentation of B3, B6 and Bacillus stearothermophilus, the highest viable cell count reached to $1.4{\times}10^{10}/ml$ in 8 hours.

• Journal of Life Science
• /
• v.13 no.6
• /
• pp.843-848
• /
• 2003

Diarrllea and death of chicken have been brought about by fowl typhoid caused by Salmonella gallinarum, which causes a great loss of chicken farms. For the development of the probiotic which can control a fowl typhoid of S. gallinarum without any adverse effect of commercial existing antibiotics, we isolated antagonistic intestinal bacteria against S. gallinarum from a bowel of the chicken which was pastured in a chicken farm of Gumi, Kyoungbuk. An Y3 strain which had a strong antagonistic ability to S. gallinarum was selected as a candidate of chicken probiotic microorganism among isolated strains. It was identified as a Bacillus amyloliuefaciens by 98% similarity by the result of cultural, physiological, biochemical test and Biolog system$(Microlog^{TM} 4.0)$, and named as Bacillus amyloliquefaciens Y3. The strain showed the strongest antagonistic activity and a good growth at pH 5-9, $37^{\circ}C.$