• Journal of Dairy Science and Biotechnology
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• v.34 no.4
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• pp.231-237
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• 2016

Kefir is a probiotic food. Probiotics have shown to be beneficial to health, and are currently of great interest to the food industry. Hence, this study was carried out to evaluate the lactase activity of kefir-isolated lactic acid bacteria. Three strains, Lactobacillu kefiri DH5 isolated from the kefir grains and Bifidobacterium animalis subsp. Lactis and Bifidobacteria longum 720, commercial probiotic LAB, were fermented in 10% reconstituted nonfat dry milk suspensions and incubated at $37^{\circ}C$ for 48 h, and then analyzed for various saccarides by HPLC. The results showed that changes in the concentrations of lactose and galactose were significantly decreased and increased, respectively (p<0.05), but all 3 probiotic strains tested in this study showed no increase in glucose concentration during 48 h of incubation. Both DH5 and BL720 showed high lactase activities (p<0.05), whereas BLC exhibited the lowest activity. Additionally, all three lactic acid bacteria showed high tagatose, but did not show high xylose and sedoheptulose. Finally, DH5, a kefir-isolated LAB, may have similar characteristics and properties to typical Bifidobacterium spp. and showed higher lactase activity than commercial Bifidobacterium spp.

• Animal Bioscience
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• v.35 no.4
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• pp.556-566
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• 2022

Objective: This study aimed to determine the appropriate supplementation level of lactic acid bacteria (LAB; Lactobacillus plantarum and Bacillus clausii), yeast (Saccharomyces cariocanus and Wickerhamomyces anomalus) for degrading free gossypol and glucosinolate in the fermented total mixed ration (TMR) containing cottonseed meal (CSM) or rapeseed meal (RSM), to improve the utilization efficiency of these protein sources. Methods: For LAB, L. plantarum or B. clausii was inoculated at 1.0×10⁸, 1.0×10⁹, 1.0×10¹⁰, and 1.0×10¹¹ colony-forming unit (CFU)/kg dry matter (DM), respectively. For yeast, S. cariocanus or W. anomalus was inoculated at 5×10⁶, 5×10⁷, 5×10⁸, and 5×10⁹ CFU/kg DM, respectively. The TMR had 50% moisture and was incubated at 30℃ for 48 h. After fermentation, the chemical compositions, and the contents of free gossypol and glucosinolate were determined. Results: The results showed that the concentration of free gossypol content was reduced (p<0.05), while that of the crude protein content was increased (p<0.05) in the TMR containing CSM inoculated by B. clausii (1×10⁹ CFU/kg DM) or S. cariocanus (5×10⁹ CFU/kg DM). Similarly, the content of glucosinolate was lowered (p<0.05) and the crude protein content was increased (p<0.05) in TMR containing RSM inoculated with B. clausii (1×10¹⁰ CFU/kg DM) or S. cariocanus (5×10⁹ CFU/g DM). Conclusion: This study confirmed that inclusion of B. clausii with 1.0×10⁹ or 1.0×10¹⁰ CFU/kg DM, or S. cariocanus (5×10⁹ CFU/kg DM) to TMR containing CSM/RSM improved the nutritional value and decreased the contents of anti-nutritional factors.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.276-286
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• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.233-239
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• 1999

This study was performed to evaluate the effects of the supplementation of lactic acid bacterias (LAB; S. thermophilus, L. acidophilus) aluminum accumulation and function kidney in rats treated with 250 g/g aluminum sulfate for 4 weeks. Fifty male Sprague Dawley strains were divided into five groups according to the types of supplement. the control, S. thermophilus culture group(A), autoclaved S. thermophilus culture(B), L. acidophilus culture group(C) and autoclaved L. acidophilus(D). The weight gain was increased by supplementation of S. thermophilus culture(A), autoclaved S. thermophilus culture(B), L. acidophilus culture(C), autoclaved L. acidophilus culture(D), especially by supplementation of S. thermophilus cultured(A) as compared to control group. The amount of water intake was increased in control group as compared to the LAB supplemented group. The content of aluminum were decreased 19.57%, 31.25%, 37.10%, and 32.40% in kidney after supplementation of non autoclaved culture group (A,C), and autoclaved group(B,D) respectively, as compared to control group. Water balance, urine volume, and excretion of sodium and potassium decreased in LAB supplemented group and control group. Excretion of creatinine increased in control group and tendency to increased in LAB supplemented group. In conclusion, the effect of suppression of aluminum accumulation was more effective in sup plementation of S. thermophilus culture(A), and L. acidophilus culture(C) than autoclaved S. thermo philus culture(B), and L. acidophilus culture(D).

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.936-942
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• 2002

When used in combination with organic acids, Pediococcus acidilactici K10 or its bacteriocin was effective in inhibiting Escherichia coli O157:H7 in vitro and in situ. P. acidilactici K10, a strain of bacteriocin-producing lactic acid bacteria (LAB), was previously isolated from kimchi in our laboratory, and the molecular weight of its bacteriocin was estimated to be around 4,500 Da by SDS-PAGE. Initially, P. acidilactici K10 and its bacteriocin could not inhibit E. coli O157:H7, when used alone. However, when they were used together with organic acids such as acetic, lactic, and succinic acids, they greatly inhibited E. coli O157:H7 in vitro. Based on these in vitro results, a real sample test with ground beef was conducted at $4^{\circ}C$ with acetic acid (0.25%) or lactic acid (0.35%) alone, and then in combination with P. acidilactici K10 (10^5 CFU/g of sample). Combined treatment of P. acidilactici K10 with lactic acid showed the most inhibitory effect: a 2.8-$log_{10}$-unit reduction of E. coli O157:H7 in ground beef during storage at $4^{\circ}C$. This result suggests that the combination of bacteriocin-producing P. acidilactici K10 and organic acids has great potential as a food biopreservative by inhibiting the growth of E. coli O157:H7.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.354-366
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• 2021

Limited data about the effects of various factors on forage quality and β-carotene content of rye produced in Korea are available, so this study investigated the effects of two preservation methods. Samples were collected from rye harvested every 5 days between April 25 and May 31, and comparisons were done among rye silage wilted for different periods of time and hay of three growth stages of rye. For the silage, dry matter (DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents increased with advanced maturity of rye, whereas crude protein, in vitro dry matter digestibility (IVDMD), total digestible nutrients (TDN), relative feed value (RFV), and DM loss decreased (p < 0.0001). Wilting increased the DM content and pH value significantly (p < 0.0001). Silage harvested at the heading stage had the lowest pH value (4.45), propionic acid (0.83 g/kg DM), butyric acid (0 g/kg DM), and fungi and yeast populations (3.70 Log CFU/g of fresh matter [FM]); conversely, it had the highest lactic acid (9.7 g/kg DM), lactic acid bacteria (LAB) (6.87 Log CFU/g of FM), total microorganisms (TM) (7.33 Log CFU/g of FM), and Flieg's score (70) (p < 0.0001). Wilting elevated LAB and TM populations, but it had no consistent effect on other fermentation products. Both delayed harvest and prolonged wilting decreased β-carotene content. Rye silage harvested around May 9 (heading stage) with 24 h of wilting was preferred for highland, Pyeongchang. For rye hay, advanced maturity decreased DM loss, IVDMD, TDN, and RFV, but it increased DM, ADF, and NDF significantly (p < 0.05). β-carotene was decreased by delay of hay-making. Consequently, to attain lower DM loss and higher hay quality, the harvest date of May 9 (heading stage) is recommended.

• Food Engineering Progress
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• v.14 no.3
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• pp.208-216
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• 2010

Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.8
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• pp.1233-1241
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• 2020

Objective: The present investigation was aimed to explore the potential of lactobacilli for conjugated linoleic acid (CLA) production, isolated from rumen fluid samples of lactating goats. Methods: A total of 64 isolates of lactobacilli were obtained using deMan-Rogosa-Sharpe (MRS) agar from rumen fluid of goats and further subjected to morphological and biochemical characterizations. Isolates found as gram-positive, catalase negative rods were presumptively identified as Lactobacillus species and further confirmed by genus specific polymerase chain reaction (PCR). The phylogenetic tree was constructed from the nucleotide sequences using MEGA6. Results: Out of the 64 isolates, 23 isolates were observed positive for CLA production by linoleate isomerase gene-based amplification and quantitatively by UV-spectrophotometric assay for the conversion of linoleic acid to CLA as well as gas chromatography-based assay. In all Lactobacillus species cis9, trans11 isomer was observed as the most predominant CLA isomer. These positive isolates were identified by 16S rRNA gene-based PCR sequencing and identified to be different species of L. ingluviei (2), L.salivarius (2), L. curvatus (15), and L. sakei (4). Conclusion: The findings of the present study concluded that lactic acid bacteria isolated from ruminal fluid samples of goat have the potential to produce bioactive CLA and may be applied as a direct fed microbial to enhance the nutraceutical value of animal food products.

• Microbiology and Biotechnology Letters
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• v.47 no.3
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• pp.434-440
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• 2019

Lactic acid bacteria (LAB) isolated from kimchi were studied for their ${\beta}$-glucuronidase activity. Among the 156 strains tested, 52 strains utilized glucuronic acid as a carbon source and their intracellular ${\beta}$-glucuronidase activities were significantly higher than their extracellular activities. Leuconostoc mesenteroides KFRI 73007 isolated from turnip kimchi exhibited the highest intracellular ${\beta}$-glucuronidase activity of $0.77{\pm}0.01U/mg$ protein, which was further increased to $1.14{\pm}0.01U/mg$ protein under optimized reaction conditions (pH 7, $37^{\circ}C$). The activity of ${\beta}$-glucuronidase was notably decreased by the addition of divalent cations, and glucuronic acid was the best carbon source to produce ${\beta}$-glucuronidase in Leu. mesenteroides KFRI 73007.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.178-186
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• 2009

To examine their potential as probiotics, acid and bile tolerance, antibiotics resistance, adhesion capacity to Caco-2 and HT-29, and antibacterial activity, of LAB isolated from Korean fermented foods such. as dongchimi, kimchi, Meju, and doenjang were assayed against foodborne pathogenic bacteria. DC 55, DC 136, DC 222, KC 21, KC 24, KC 34, KC 43, KC 117, MJ 54, MJ 301, SP 33, and SP 170 strains were resistant to acid and bile conditions. In particular, DC 55, DC 136, KC 24, KC 43, and MJ 301 strains were highly resistant to higher than 20 ${\mu}g/ml$ concentrations of vancomycin, streptomycin sulfate, or amoxicillin, whereas, DC 222, KC 21, KC 34, KC 117, MJ 54, and SP 33 strains were susceptible to lower than 2 ${\mu}g/ml$ concentrations of those antibiotics. The adhesion to HT-29 and Caco-2 cells varied with the strains tested in a strain-dependent manner. The highest level of adhesion was observed with DC 55, KC 21, KC 24, and MJ 301 strains, having higher than 50% of adhesion to HT-29 or Caco-2 cells. In addition, Staphylococcus aureus was the most sensitive to KC 21, showing an inhibition of about 70%, and the antibacterial activity of KC 21 against S. aureus resulted most likely from both organic acids and bacteriocin. Based on its phenotypic characteristics and utilization of various sugars, the KC 21 strain was identified as Lactobacillus plantarum.