• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.289-296
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• 1985

A simple procedure for rapid isolation of plasmid DNA from lactobacillus species and streptococcus species is described. Lactic acid bacteria were cultured in the TCM broth containing 0.5％ glycine and plasmid DNA was isolated from cells treated with mutanolysin by alkaline-detergent lysis method. Good results for releasing and isolating plasmid DNA from lactobacillus species were obtained by treatment of cells with 30$\mu\textrm{g}$ of mutanolysin per ml at 37$^{\circ}C$ for 5 to 10 min. For the streptococcus species, the optimum conditions were slightly different. The procedure could be used for rapid characterization of plasmid DNA in Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus helveticus, Streptococcus lactis, Streptococcus faecalis, Streptococcus faecium, and Streptococcus cremoris strains. Using this procedure, plasmids isolated from $1.5m\ell$ cultures could readily be visualized in agarose gel.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.732-741
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• 2009

This study was carried out to identify lactic acid bacteria isolated from commercial Kimchi. Twelve lactic acid bacteria strains were isolated from Chinese cabbage kimchi (Baechu kimchi) that was fermented for 4 days at room temperature after making kimchi, 6 strains from pickled ponytail radishes (Chongkak kimchi) that was fermented for 2 days, and 15 strains in radish cube kimchi (Kaktugi) that was fermented for 5 days, and 23 strains were isolated in pickled Wakegi (Pa kimchi) that was fermented for 4 days. Eight strains among the lactic acid bacteria of 12 strains isolated from Baechu kimchi (pH 4.0) were identified as Lactobacillus plantarum, 1 strain as Leuconostoc lactis, 2 strains as Lactobacillus casei subsp. pseudoplantarum, and 1 strain as Lactobacillus sake. Three strains among the lactic acid bacteria of 6 strains isolated from Chongkak kimchi (pH 4.5) were identified as Leuconostoc paramesenteroides, 2 strains as Leuconostoc mesenteroides subsp. mesenteroides, and 1 strain as Lactobacillus plantarum. Two strains among the 15 strains isolated in Kaktugi (pH 4.0) were identified as Leuconostoc lactis, 3 strains as Leuconostoc mesenteroides subsp dextranicum, 4 strains as Lactobacillus casei subsp. pseudoplantarum, and 4 strains as Lactobacillus coryniformis subsp. torquens. Twenty-two strains among the 23 strains isolated from Pa kimchi (pH 4.1) identified as L. plantarum and 1 strain was as Lactobacillus sake. From the results above, the dominant species of Baechu kimchi was confirmed as L. plantarum, Chongkak kimchi as L. paramesenteroides, Kaktugi as L. casei subsp. pseudoplantarum and L. coryniformis subsp. torquens, and Pa kimchi as L. plantarum.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.120-132
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• 1984

In order to clarify the effect of the fish meat hydrolysate on the growth of lactic acid bacteria(Str. lactis, Str. thermophibus, L. bulgaricus, L. acidophilus, and L. helveticus), the optimum conditions for hydrolyzing the fish meat were examined, and changes of the acid production, viable cell count of lactic acid bacteria and the charge of pH of the culture medium by addition of the fish meat hydrolysate were tested. The results were as follows: 1. When the hydrolysis of back muscle of mackerel was proceeded at $50^{\circ}C$ and at pH 8, for 48 hours adding 6% pancreatin of the protein content in the substrate, the best result was obtained. 2. The composition of the fish meat hydrolysate were 53.6% moisture, 32.4% protein, 1.0% fat, 10.7% carbohydrate, and 3.2% ash. 3. Above 0.1% of the fish meat hydrolysate in the culture medium, the acidity of the culture medium by Sir. lactis and Str. thermophilus were increased remarkably. The acidity of the culture medium by L. acidophilus and L. helveticus were increased in above 0.2% fish meat hydrolysate in the culture medium. but L. bulgaricus was not effected by the fish meat hydrolysate. 4. The pH of the culture medium during incubating Str. laclis and Sir. thermophilus failed obviously by adding the fish meat hydrolysate. But in the cases of L. bulgaricus, L. acidophilus, and L. helveticus, the pH were not changed clearly. 5. The viable cell count in all bacterial strains tested here were elevated by increasing the concentration of the fish meat hydrolysate.

• Food Science and Preservation
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• v.16 no.2
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• pp.266-275
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• 2009

To develop new high-quality Yakchobugak, features of Lactococcus lactis-fermented waxy rice paste after addition of some colored powdered agro-food products were investigated. Total and reducing sugars of waxy rice paste fermented by lactic acid bacteria were higher than those of control raw waxy rice paste. Total acidity gradually increased as powder concentration rose, being 1.02-1.56% and 0.96-1.87% in samples fermented with Cucurbita maxima and Capsicum annuum powders, respectively; these values were 3-4 times those in rice fermented with other powders. Fermented waxy rice paste viscosities were lower than those of non-fermented samples. The viscosities of samples fermented with Curcuma longa and Opuntia ficus powders were in the range $100-160{\times}10^4$ centipoise($mPa{\cdot}s$), and those of pastes fermented with Robus coreanus and Camellia sinensis extracts were under $40{\times}10^4mPa{\cdot}s$. Hunter color lightness(L) values decreased and yellowness(b) values rose after fermentation. Waxy rice paste fermented with Robus coreanus showed uniform particle size distribution, and many pores, by scanning electron micrography.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.303-310
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• 2002

An optimization for fermentation processes to make lactic acid juice with extracts from apples, carrots, celery, watercress, jujube and lycii (3 : 3 : 1 : 1/2 : 1 : 1/2) using co-cultures of Leuconostoc mesenteroides, Lactococcus lactis and Lactobacillus cellobiosus isolated from Dongchimi had been investigated on the emphasis of composition of sugars and sodium chloride at various temperatures. The concentration of sugars less than 25% and salt less than 0.8% did not affect remarkably the cell growth of lactic acid bacteria and acid formation during fermentation. The fermenting juice showed increases in the population of lactic acid bacteria and acidity, and decreases in population of coliform bacteria and sugar concentration with high cultural temperature. At $25^{\circ}C$ viscous substance was not formed as it had at $15^{\circ}C$. The optimum composition, based on the sensory evaluation, was determined to be oligosaccharide and 0.2% for sodium chloride. It took 3 days to produce the most preferable juice of pH 3.62 at $25^{\circ}C$. At the optimal state the fermented juice showed viable cell counts (cfu/mL) of exponential numbers 8 for lactic acid bacteria and 4 for yeast. Coliform bacteria which had been $5.6{\times}10^2\;cfu/mL$ at the beginning of fermentation were not detected.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.528-534
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• 1992

Growth stimulatory material for lactic acid bacteria was extracted from radish and radish green juice and its growth stimulatory effect was tested. Dried methanol-precipitated growth stimulatory material was lightly grayish white powder, Its ash content is 44% and approximately 50% of the ash is sulfur. It has reddish brown color upon solubilization in water. The material had unchanged stimulatory effect when it was treated with proteinase or pectinase, or ashed. The growth stimulatory activity was dialyzable. The material was able to counteract the growth inhibitory effect of EDTA. When selected lactic acid bacteria were grown at $30^{\circ}C$ for 24 hours in peptone(0.5%)-yeast extract(0.5%)-glucose(2%) broth with and without 0.5% growth stimulatory material, the material stimulated the growth of Lactobacillus plantarum, L. fermentum, L. leichmanii, L. sake, L. brevis, L. acidophilus, L. casei, Pediococcus pentosaceus, Leuconostoc mesenteroides, Streptococcus faecalis, S. lactis, S. cremoris and S. thermophilus by 19, 1833, 133, 444, 840, 32, 14, 18, 6, 17, 4, 5 and 4 times, respectively.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.907-920
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• 2006

This study was conducted to investigate the inhibitory activity of Lactobacillus spp., Bacillus ssp., and calf fecal isolates against pathogenic Salmonella typhimurium, E. coli, Listeria monocytogenes, and Staphylococcus aureus. Among thirteen strains of Lactobacillus ssp. tested, Lactobacillus helveticus CU631 showed the highest inhibition against three pathogens, whereas Bacillus spp. showed a weak inhibitory activity. Four calf fecal isolates were identified as Lactobacillus pentosus CU13, CU05, Pediococcus pentosaceus CUR02, and Lactobacillus lactis ssp. lactis CUM14. The whole cell and cell wall components of L. rhamnosus CU02 and L. pentosus CU13 were active in the inhibition of L. monocytogenes. The medium components and levels, which affect on the inhibitory activity, were revealed as Tween 80 1.0%, peptone 3.0%, yeast extract 3.0%, glucose 3.0%, beef extract 3.0%, and NaCl 1.0～3.0%, respectively. Inhibitory activity of the supernatant culture medium was not affected by catalase and proteinase K treatment but affected by heat treatment at 80℃ and netralization, which implies that the inhibitory activity is due to the production of organic acids during the growth. L. pentosus CU13 and L. rhamnosus CU02 exhibited broad inhibition spectrum against 16 out of 21 strains including some pathogens. Oral administration of L. rhamnosus CU02 to the mice infected with E. coli O157:H7 was proven to be effective to recover their body weight during the experimental period.

• Journal of Dairy Science and Biotechnology
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• v.26 no.2
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• pp.31-37
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• 2008

One hundred one years have passed since Metchnikoff made his first scientific contribution to probiotics study. Intestinal lactic acid bacteria (LAB) for humans are closely associated with the host's health because LAB is an important biodefense factor in preventing colonization and subsequent proliferation of pathogenic bacteria in the intestine. A probiotic is recently defined as "live microorganisms that when administered in adequate amount confer a health benefit on the host". Some species of LAB have been claimed as probiotics, such as Lactobacillus acidophilus, L. casei, L. fermentum, L. plantarum, L. reuteri, and Lactococcus lactis. For understanding the general mechanism of probiotics, this paper would explore the early studies relating to probiotics and intestinal microbiota, and briefly introduce the Prolongation of Life written by Elie Metctmikoff.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.644-648
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• 1994

Lactic acid bacteria(LAB) and its metabolites were tested for their inhibitory effect on the growth of Staphylococcus aureus in vitro. When S. aureus and LAB were incubated simultaneously in MRS broth, the growth of S. aureus began to be suppressed after 12 hour of incubation, completely inactivated within 24 hour of incubation by L. lactis and 48 hour by L. casei, L. acidophilus, and Sc. thermophilus. The pH values of media incubated by S. aureus and LAB were about 4.5 at 12 hour of incubation and 3.5 at 48 hour. The metabolites of the four LAB all exerted antibacterial activity on the growth of S. aureus in TS broth, but is got lost the antibacterial activity by heating ($100^{\circ}C,\;20\;min$). On treating metabolites with catalase, only L. lactis were lost its antibacterial activity. Organic acids (acetate, lactate) showed more active inhibition than inorganic acid (HCl) at pH 3.5, 4.5 but there is no significant differance at pH 5.5, 6.5.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.6
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• pp.700-707
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• 2010

Effects of protease-resistant antimicrobial substances (PRA) produced by Lactobacillus plantarum and Leuconostoc citreum on rumen methanogenesis were examined using the in vitro continuous methane quantification system. Four different strains of lactic acid bacteria, i) Lactococcus lactis ATCC19435 (Control, non-antibacterial substances), ii) Lactococcus lactis NCIMB702054 (Nisin-Z), iii) Lactobacillus plantarum TUA1490L (PRA-1), and iv) Leuconostoc citreum JCM9698 (PRA-2) were individually cultured in GYEKP medium. An 80 ml aliquot of each supernatant was inoculated into phosphate-buffered rumen fluid. PRA-1 remarkably decreased cumulative methane production, though propionate, butyrate and ammonia N decreased. For PRA-2, there were no effects on $CH_4$ and $CO_2$ production and fermentation characteristics in mixed rumen cultures. The results suggested that PRA-1 reduced the number of methanogens or inhibited utilization of hydrogen in rumen fermentation.