• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1031-1035
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• 2002

This study was carried out to obtain conjugated linoleic acid (CLA) producing lactic acid bacteria for further study on the enzymes related to the production of CLA which has gained considerable attention and on the development as a probiotic culture. Total 34 lactic acid bacteria were isolated from 19 feces samples of healthy babies. CLA forming ability was measured spectrophotometrically by the modification of linoleate 12-cis, 11-trans-isomerase activity measuring method, and CLA of the cultures were extracted, methylated, and examined by HPLC analysis. CLA methyl ester of only one culture showing the highest value of CLA forming ability could be detected by HPLC analysis. The culture was found to be Gram positive, rods and catalase negative. It grows at $45^{\circ}C$ but not at $15^{\circ}C$, and was identified to be Lactobacillus fermentum on the basis of the biochemical characteristics and the utilization of substrates. These results provide an efficient experimental method to screen CLA producing lactic acid bacteria.

• The Korean Journal of Food And Nutrition
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• v.6 no.1
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• pp.1-7
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• 1993

19 Samples of koji-starters using in brewing were collected from Korea and Japan, and then 31 strains of koji-molds were isolated from them. After Identification of the Isolate, rice koji was made with each strains, and its saccharogenic activity, dextrogenic activity, proteolytic activity, acid Producing ability, browning reaction and flavor were tested. Among 31 strains of isolates, 10 strains were Identified as Asp nwamori var. kawachii, 18 strains as Asp. oryzae, 3 strains as Asp. usamii mkt. shirousamii. The koji-starters made in Korea were composed of single species of koji-mold with same strain, but those made in Japan were composed of the mixture of different two species or the mixture of different 2 ∼4 strains in same species. Judging from amylolytic and proteolytic ability by species, Asp. awamori var. kawachii H1, I1 and 11, Asp. owsae J2, L2, M2, P3 and P4, and Asp. usamii writ. shirousamii S1 were better than the others. Mold strains isolated from Korean koji-starters were much lower in amylolytic or proteolytic activity than those from Japanese koji-starters. The typical characteristics for the 3 species of koji-molds were that Asp. awamori var. kawachii was strong in acid producing ability, but week in amylolytic and proteolytic ability, that Asp. owzae had strong amylolytic activity and good aroma, but produced little amount of acid, and that Asp. usamii mut. shirousamii had strong Proteolytic activity but some off-flavor.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.104-109
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• 2007

Lactic acid bacteria that accumulated ${\gamma}-aminobutyric$ acid (GABA) in culture medium were screened to identify strains with high GAB A-producing ability. One strain, MS, which was isolated from kimchi, showed the highest GABA-producing ability among the screened strains. MS was identified as Lactobacillus buchneri based on Gram-staining, metabolic characteristics, and 16S rDNA sequence determination, Optimum culture conditions for GABA production were determined: MRS broth containing 5% MSG, 1% NaCl, and 1% glucose, at an initial pH of 5.0, the incubation temperature at $30^{\circ}C$ for 36 h. Under these conditions, MS produced GABA at a concentration of 251 mM with a 94% GABA conversion rate. Moreover, culture extracts of Lb. buchneri MS partially or completely protected neuronal cells against neurotoxicantinduced cell death.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.660-666
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• 2003

The purpose of this study was to investigate the inhibitory effect of Er:YAG laser against the intraoral acid producing bacterium of S. mutans. Bacterial pellet containing S. mutans KCTC 3065 was irradiated by Er:YAG laser having a $650\;{\mu}m$ diameter beam by non-contact mode. Irradiated parameters were 50mJ, 10Hz and exposure time were 1s, 3s, 5s, 7s, 9s respectively. We obtained the following results of relative growth rate and acid-producing ability of S. mutans by culturing for 48hrs. 1. The growth rate of S. mutans was decreased in the group of laser irradiation compared to the control group(P<0.01). 2. The growth rate at laser irradiation group of 7s, 9s irradiation time was decreased significantly compared to the laser irradiation group of 1s, 3s, 5s irradiation time, until 12 hours(P<0.05). After 24 hours, all groups of laser irradiation were not found to be statistically different in each other. 3. The acid-producing ability of S. mutans was inhibited for a certain duration by irradiation of laser. In summary, the growth rate and acid producing ability of S. mutans decreased according to laser irradiation. This effect was directly related to the amount of irradiation time. These results suggested that Er:YAG laser had an growth inhibition effect on S. mutans.

• Journal of Dairy Science and Biotechnology
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• v.28 no.2
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• pp.31-39
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• 2010

Lactic acid bacteria (LAB) are typical probiotic microbes which are used in various industries including fermented foods, feed additives, and pharmaceuticals. The purpose of this study was to compare the ability of antioxidative activities of 23 strains of LAB isolated from cheese, kimchi, yogurt, and etc. LAB were tested for antioxidative activities such as 2,2'- azino-bis(3-ethyl-benzothiazoline-6-sulphonic acid) (ABTS) radical scavenging abilities and superoxide dismutase (SOD)-like ability. Antioxidative activities were examined different media such as MRS, M17, and 10% skim milk. Culture supernatant in M17 medium showed a higher antioxidative activity than these in MRS and 10% skim milk. Comparison of ABTS radical scavenging ability by the LAB showed a wide variation with a range from 9~93% and SOD-like ability of LAB ranged from 70~78%, respectively. Therfore, some of LAB can play important roles in the protection for oxidative stress and CPP-producing activity of LAB may be a promising material for application in the dairy industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1348-1352
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• 2004

More than 200 Bifidobacterium sp. originated from human intestine were investigated for their ability to produce conjugated linoleic acid (CLA). Of the Bifidobacteria tested, 1 of culture type strain and 12 isolated strains from Korean infants showed CLA producing ability. cis-9, trans-11 octadecadienoic acid presented more than 90% of the total CLA isomers produced by the Bifidobacteria. CLA content in fermented milk by Bifidobacterium sp. KHU 141 increased by 39.6 mg/l00 g, which showed the potential use for producing fermented milk containing high content of CLA. In fermented milk, little changes showed in lauric acid, myristric acid, palmitic acid, oleic acid, and linolenic acid contents, whereas the content of linoleic acid (LA) decreased and the content of CLA increased. Bifidobacterium sp. KHU 141 converted 86.0% and 84.8% of LA consumed to CLA for 24 hr and 48 hr fermentation, respectively. Prolonging incubation from 24 to 48 hours did not appear to enhance CLA formation and CLA producing ability was stable whether bottle, test tube, or fermenter was used for making fermented milk by Bifidobacterium sp. KHU 141.

• Mycobiology
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• v.34 no.1
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• pp.22-29
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• 2006

Forty-one fungal species belonging to 15 fungal genera isolated from Egyptian soil and sugar cane waste samples were tested for their capacity of producing acidity and gluconic acid. For the tests, the fungi were grown on glucose substrate and culture filtrates were examined using paper chromatography analysis. Most of the tested fungi have a relative wide potentiality for total acid production in their filtrates. Nearly 51% of them showed their ability of producing gluconic acid. Aspergillus niger was distinguishable from other species by its capacity to produce substantial amounts of gluconic acid when it was cultivated on a selective medium. The optimized cultural conditions for gluconic acid yields were using submerged culture at $30^{\circ}C$ at initial pH 6.0 for 7 days of incubation. Among the various concentrations of substrate used, glucose (14%, w/v) was found to be the most suitable carbon source for maximal gluconic acid during fermentation. Maximum values of fungal biomass (10.02 g/l) and gluconic acid (58.46 g/l) were obtained when the fungus was grown with 1% peptone as sole nitrogen source. Influence of the concentration of some inorganic salts as well as the rate of aeration on the gluconic acid and biomass production is also described.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.13-17
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• 1994

We estabilished the procedure for isolation of Streptococcus salivarius subsp. thermophilus from raw milk. First, urease-producing lactic acid bacteria in raw milk were screened on the HY agar medium containing urea. Thereafter the urease-producing colonies were tested the ability to ferment maltose and to grow at43$\circ $C. We obtained about 400 maltose-negative colonies that grew at 43$\circ $C. No significant difference in carbohydrate fermentation test for isolated and type strains(S. salivarius subsp. thermophilus ATCC 19258 and ST-4) was found. And all of the isolated strains were able to ferment galactose. Furthermore, it was investigated that the cellular fatty acid profiles of isolated strains were similar to that of type strains. These results indicated that the isolated strains from raw milk were S. salivarius subsp. thermophilus. But when the isolated and type strains were incubated in 12% reconstituted skim milk at 43$\circ $C, the isolates produced lactic acid more slowly than the type strains.

• KSBB Journal
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• v.17 no.2
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• pp.137-141
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• 2002

Levan oligosaccoharides and low molecular weight levin were produced from levin by acid hydrolysis and following column chromatography. Levan hydrolysis was progressed proportionally as increased incubation time. In terms of levan hydrolysis reaction, no differences were found from the sources of levan. Optimum hydrolysis conditions for the formation of levan oligosaccharides were, 0.38 M H$_2$S0$_4$; and incubation at 95$\^{C}$ for 4 min. The purified products were determined as the mixture of oligosaccharides (degree of polymerization (DP) of 3-6), Two of lactic acid-producing bacteria, Lactobacillus plantarum KCTC 3104 and Pediococcus pentosaceus KCTC 3507, were studied in vitro for their ability to metabolize levin oligosaccharides. Apparently, the growth of both cells were increased by levin oligosaccharide diet, compared with those of levan diets, suggesting that levan oligosaccharides may be beneficial in selectively growth of lactic acid-producing bacteria.

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.42.1-42.10
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• 2016

The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB) isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0-8.0 and heating for 10 min at $80^{\circ}C$; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, ${\alpha}$-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.