• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1872-1877
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• 2013

Lactic acid bacteria were selected on the basis of lactic acid producing ability from kimchi, a traditional Korean fermented food. Among the initial screening of over 150 strains selected from the sample, 27 strains were selected as lactic acid producing bacteria, and 4 strains were finally selected based on their ability to produce relatively high levels of lactic acid. The four strains were identified as Lactobacillus (L.) plantarum Gk04, Pediococcus pentosaceus Gk07, L. brevis Gk35 and L. curvatus Gk36 by the conventional morphological, cultural, physiological and biochemical characteristics, as well as by 16S rRNA sequence analysis. Among the identified lactic acid bacteria, L. curvatus Gk36 was used for soymilk fermentation. The viable cell counts and acidity values measured for the L. curvatus Gk36 were comparable to the commmercial L. acidopillus. Thus, the L. curvatus Gk36 is a potential probiotic strain to prepare fermented soy products, such as kephir, yogurt, tempeh and soy sauce.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.473-478
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• 2015

The aim of this study was to screen and In vitro characterize the properties of bacteriocin produced by lactic acid bacteria isolated from Vietnamese fermented pork (Nem chua). One hundred and fifty LAB were isolated from ten samples of Nem chua and screened for bacteriocin-producing lactic acid bacteria. Antimicrobial activity of bacteriocin was carried out by spot on lawn method against both gram positive and gram negative bacteria. One isolate, assigned as KL-1, produced bacteriocin and showed inhibitory activity against Lactobacillus sakei, Leuconostoc mesenteroides and Enterococcus faecalis. To characterize the bacteriocin-producing strain, optimum temperature, incubation period for maximum bacteriocin production and identification of bacteriocin-producing strain were determined. It was found that the optimum cultivation temperature of the strain to produce the maximum bacteriocin activity (12,800 AU/mL) was obtained at 30℃. Meanwhile, bacteriocin production at 6,400 AU/mL was found when culturing the strain at 37℃ and 42℃. The isolate KL-1 was identified as L. plantarum. Antimicrobial activity of cell-free supernatant was completely inhibited by proteolytic enzyme of trypsin, alpha-chymotrypsin and proteinase K. Bacteriocin activity was stable at high temperature up to 100℃ for 10 min and at 4℃ storage for 2 d. However, the longer heating at 100℃ and 4℃ storage, its activity was reduced.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.282-291
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• 1999

Lactic acid bacteria were isolated from Kimchi and screened for bacteriocin. A total of 99 strains showed antimicrobial activity when grown on solid media, yet only 10 showed antimicrobial activity in liquid media. Strain H-559, identified as Lactococcus lactis subsp. lactis, exhibited the strongest inhibitory activity and was active against pathogenic bacteria including Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus as well as other lactic acid bacteria. The antimicrobial substance produced by L. lactis subsp. lactis H-559 was confirmed to be a bacteriocin by the treatment of $\alpha$-chymotrypsin, and protease type Ⅸ and ⅩIV. The bacteriocin activity remained stable between pH 2.0 and pH 11.0 and during heating for 10 min at $100^{\circ}C$. The bacteriocin production started in the exponential phase and stopped in the stationary phase. L. lactis subsp. lactis H-559 showed the highest bacteriocin activity at a culture temperature of $25^{\circ}C$, and an inverse relationship between the bacteriocin productivity and mean growth rate at different culture temperatures was observed. The mean growth rate and bacteriocin productivity of L. lactis subsp. lactis H-559 increased as the initial pH of the media increased.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.503-508
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• 2005

Screening for antilisterial activity was performed in about three thousand isolates of lactic acid bacteria (LAB) from Chinese cabbage kimchi, and finally based on the relatively stronger antilisterial activities eight bacterial strains were selected. The bacteria were further characterized in terms of their tolerance to artificial gastric juice, pH 2.5, bile salts (0.3% oxgall), and to the different NaCl concentrations. Of the isolates, YK005 was especially investigated for its physiological characteristics due to its inhibitory activity against gram-positive Listeria monocytogenes as well as gram-negative Escherichia coli O157:H7, as they have been constantly reported to be resistant against bacteriocins produced by a number of LAB strains. YK005 was found to be rod-shaped, $3.8\;{\mu}m$ long ${\times}\;0.5\;{\mu}m$ wide, non-sporeforming, non-motile, catalase-negative, and produced gas from glucose (heterolactic). Based on the biochemical data obtained by API 50 CHL medium, the isolate was tentatively identified as Lactobacillus brevis. To validate the result obtained by the biochemical identification, rRNA-based PCR experiments using a pair of species-specific primers for L. brevis were conducted and a single band of 1400 bp was observed, which strongly indicated that YK005 belongs to L. brevis. The LAB isolates are potentially exploited as human probiotic organisms and are employed to control some food-borne pathogens like L. monocytogenes.

• Food Engineering Progress
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• v.21 no.3
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• pp.242-248
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• 2017

The acidity of soy curd fermented by lactic acid bacteria is a major factor degrading the sensory properties of soy curd. For preparation of soy curd with low sour taste, lactic acid bacteria were separated from kimchi. The lactic acid bacteria which showed yellow-clear zone around the colonies on BCP plate and formed soy curd with low level of acidity were selected. The selected strain was analyzed by 16S rDNA sequence and named as Pediococcus inopinatus Y2. The maximum viable cell number of the soy curd fermented by P. inopinatus Y2 was obtained at 10.73 log CFU/mL at $25^{\circ}C$ for 24 h of fermentation. By the results of panel test, the overall sensory quality of the soy curd produced by P. inopinatus Y2 was higher than that of Leuconostoc mesenteroides No. 4395 and Lactobacillus sakei strain No. 383.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1208-1212
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• 1997

Isolation and identification of predominant microorganisms in fermented squid with low salt were carried out during fermentation at $10^{\circ}C$. Dominant strains were lactic acid bacteria(80%) including Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc sp., Pediococcus sp. and Streptococcus sp. Leuconostoc, Pediococcus and Streptococcus were shown in the early stage of fermentation and gradually increased until optimum stage of squid fermentation, and then decreased rapidly. Lactobacillus grew lastingly during fermentation. Yeasts were detected in the middle stage of fermentation and shown rapid increase after the last stage of fermentation, suggesting that yeasts participate in putrefaction of fermented squid with low salt.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.384-389
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• 2009

To isolate lactic acid bacteria having high exopolysaccharides (EPS) production ability, 50 strains were initially isolated from the sourdough. Twenty-one strains formed highly mucoid colonies on the sucrose agar medium, which are indicative of active EPS synthesis. DU-07, DU-10, DU-12, DU-19, and DU-21 produced $11.51{\pm}0.167$, $13.09{\pm}0.193$, $12.72{\pm}0.108$, $11.61{\pm}0.284$, and $13.32{\pm}0.094\;g/L$ EPS, respectively, in MRS medium. The isolated strains, DU-10, DU-12, and DU-21, were identified as Enterococcus flavescens, Enterococcus faecium, and Lactobacillus amylovorus, respectively, by using API 50CHL kit and determining partial sequences of their 16S rDNA. Especially, L. amylovorus DU-21 showed the highest production of EPS, as well as the highest inhibitory activities against pathogenic (p<0.05). Interestingly, the L. amylovorus DU-21 seem to be endemic to sourdough fermentations, as they have not been isolated from other environments.

• Journal of Dairy Science and Biotechnology
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• v.18 no.1
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• pp.47-60
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• 2000

Over decades of work, the probiotic research has grown rapidly with a number of new cultures, which is claimed a variety of benefit. However, many of the specific effects attributed to the ingestion of probiotics remain convoluted and scientifically unsubstantiated. Accordingly, the scientific community faces a greater challenge and must objectively seek cause and effect relationships for many potential and currently investigated probiotic species. Rational selection and design of probiotics remains an important challenge and will require a solid information about the physiology and genetics of candidate strains relevant to their intestinal roles, functional activities, and interaction of with other resident micro flora. As far as beneficial culture of lactic acid bacteria (LAB) is concerned, simple, cost-effective, and exact identification of candidate strains is of foremost importance among others. Until recently, the relatedness of bacterial isolates has been determined sorely by testing for one or several phenotyphic markers, using methods such as serotyping, phage-typing, biotyping, and so forth. However, there are problems in the use of many of these phenotype-based methods. In contrast, some of newer molecular typing methods involving the analysis of DNA offer many advantages over traditional techniques. These DNA-based methods have the greater discriminatory power than that of phenotypic procedures. This review focuses on the importance and the basis of molecular typing methods along with some considerations on de-sign and selection of probiotic culture for human consumption.

• Journal of Life Science
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• v.25 no.7
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• pp.810-818
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• 2015

We analyzed whether lactic acid bacteria could control the expression of IL-4 and IL-13 in activated mast cells and whether these bacteria could inhibit the activity of transcription factors such as GATA-1, GATA-2, NF-AT1, NF-AT2, and NF-κB p65. We previously described a technique for identification of lactic acid bacteria with anti-atopy functionality by confirming increased expression of CD4+/CD25+/foxp3+ in T cells. We also confirmed that a double-culture method increased the antibacterial activity of these lactic acid bacteria against Staphylococcus aureus (S. aureus). In the present study, we characterized the effect of lactic acid bacteria cultured by this double-culture method on inhibition of allergic inflammatory reactions of RBL-2H3 mast cells, a cellular model of atopic dermatitis. The strongest anti-allergic effects of the lactic acid bacteria were seen in the following order: Lactococcus lactis broth cultured with medium containing Lactobacillus plantarum culture supernatant > Lc. lactis > Lc. lactis broth cultured with medium containing Lb. plantarum culture supernatant > Lb. plantarum. Thus, Lc. lactis cultured in medium containing Lb. plantarum culture supernatant had the strongest inhibitory effect on the differentiation of mast cells during allergic reactions, which may be mediated through the selective regulation of expression of relevant genes.

• Preventive Nutrition and Food Science
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• v.21 no.1
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• pp.52-56
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• 2016

This study was performed to investigate the antifungal substances and the antifungal activity against fungi of lactic acid bacteria (LAB) isolated from kimchi. LAB from kimchi in Imsil showed antifungal activity against Penicillium brevicompactum strain FI02. LAB LI031 was identified as Lactobacillus sakei subsp. Antifungal substances contained in L. sakei subsp. ALI033 culture media were unstable at high pH levels. Both, the control and proteinase K and protease treated samples showed clear zones, suggesting that the antifungal substances produced by ALI033 were non-protein substances unaffected by protesases. Both, the control and catalase showed clear zones, suggesting that the antifungal metabolite was not $H_2O_2$. The molecular weights of the antifungal substances were ${\leq}3,000Da$. The organic acid content of crude antifungal substances produced by L. sakei subsp. ALI033 showed high concentrations of lactic acid (502.47 mg/100 g). Therefore, these results suggest that antifungal substance produced by L. sakei subsp. ALI033 is most likely due to its ability in producing organic acid.