• Biotechnology and Bioprocess Engineering:BBE
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• 제9권4호
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• pp.318-322
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• 2004

Lactic acid is an environmentally benign organic acid that could be used as a raw material for biodegradable plastics if it can be inexpensively produced by fermentation. Two genes (ldhL and ldhD) encoding the L-(+) and D-(-) lactate dehydrogenases (L-LDH and D-LDH) were cloned from Lactobacillus sp., RKY2, which is a lactic acid hyper-producing bacterium isolated from Kimchi. Open reading frames of ldhL for and ldhD for the L and D-LDH genes were 962 and 998 bp, respectively. Both the L(+)- and D(-)-LDH proteins showed the highest degree of homology with the L- and D-lactate dehydrogenase genes of Lactobacillus plantarum. The conserved residues in the catalytic activity and substrate binding of both LDHs were identified in both enzymes.

• Asian-Australasian Journal of Animal Sciences
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• 제19권5호
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• pp.751-755
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• 2006

Dadih is Indonesian traditional fermented buffalo milk believed by the natives to have beneficial effects on human health. This may be due to the probiotic properties possessed by the lactic acid bacteria (LAB) involved in its fermentation process. It was discovered that ten strains of dadih lactic isolates possessed some probiotic properties in vitro. In this study, the adhesion properties of dadih LAB, in comparison with documented probiotic strains, were investigated in vitro by using mucin extracted from human faeces and Caco-2 cells as the models for human intestinal mucosal surface and intestinal cells respectively. The adhesion results showed the distinction of Lactobacillus reuteri IS-27560 in adhering to both mucus layer and Caco-2 cells. The competition assay for adhesion to the mucus layer between dadih LAB and selected pathogens indicated the competence of Lactococcus lactis IS-16183 and Lactobacillus rhamnosus IS-7257 in significantly inhibiting the adhesion of Escherichia coli O157:H7. Accordingly, these two strains may be potential candidates for use as probiotic strains. Overall, the adhesion properties of all dadih LAB strains were relatively comparable to that of Lactobacillus casei Shirota and Lactobacillus rhamnosus GG, the documented probiotic strains.

• 한국미생물·생명공학회지
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• 제24권6호
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• pp.678-686
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• 1996

To improve the preservation of Kimchi, we isolated Lactobacillus plantarum lytic enzyme-producing strain from soil, and the enzyme was purified and characterized. From the observation of cultural and morpho- logical characteristics, the isolated strain was identified as Metarrisium anisopliae (Metschn.) Sorok. The enzyme was purified to 75-folds with 40% yields through affinity adsorption and CM-Sephadex C-50 column chromatog- raphy. The optimum pH and temperature for lytic activity are 4.0 and 40$\circ$C, respectively, and the enzyme acitvity is stable between pH 3.0 and 9.0, and up to 50$\circ$C. The enzyme is a monomeric protein with molecular weight of 40,000 daltons by SDS-PAGE and gel filtration. The enzyme is endopeptidase which breaks the peptide linkage of Lactobacillus plantarum peptidoglycan. The lytic action spectra confirmed that Leuconostoc mesenteroides, a useful strain for the fermentation of Kimchi, is not lysed by the enzyme. The enzyme activity is inhibited by N-bromosuccinimide (NBS), which probably indicates the involvement of tryptophan residue in active site of the enzyme, and also inhibited by Ag$^{+}$. The amino acid composition analysis showed that the enzyme contains more acidic amino acids than basic ones, and composition of alanine, glycine, proline and tyrosines was very high.

• 한국식품영양학회지
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• 제25권3호
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• pp.629-636
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• 2012

Ginsenosides, ginseng saponin, are the principal components responsible for the pharmacological and biological activities of ginseng. In order to improve absorption and biological activities, the biotransformation of major ginsenoside to minor ginsenoside, as the more active compound, is required. In this study, we isolated Lactobacillus brevis THK-D57, which has high ${\beta}$-glycosidase activity, from Kimchi. The major ginsenoside Rb1 was converted to the minor ginsenoside 'compound K' during the fermentation of L. brevis THK-D57. The results propose that the biotransformation pathway to produce compound K is as follows: ginsenoside $Rb_1{\rightarrow}ginsenoside$ $Rd{\rightarrow}ginsenoside$ $F_2{\rightarrow}ginsenoside$ compound K.

• 한국축산식품학회지
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• 제30권5호
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• pp.795-803
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• 2010

A DF01 strain that inhibits tyramine-producing Lactobacillus curvatus KFRI 166 was isolated from Dongchimi, a traditional Korean fermented vegetable, and identified as Lactobacillus brevis by biochemical analysis and reverse transcriptase sequencing of 16S rRNA. The antimicrobial compound produced by L. brevis DF01 was secreted at a maximum level of 640 AU/mL in late exponential phase in MRS broth, and its activity remained constant during stationary phase. The activity of bacteriocin DF01 was totally inactivated by $\alpha$-chymotrypsin, pronase E, proteinase K, trypsin, and $\alpha$-amylase, but not by catalase, which indicates the compound was glycoprotein in nature. The activity was not affected by pH changes ranging from 2 to 12 or heat treatment (60, 80, and $100^{\circ}C$ for 30 min), but was reduced after autoclaving. Bacteriocin DF01 had bacteriolytic activity and a molecular weight of approximately 8.2 kDa, as shown by tricine-SDS-PAGE analysis. Therefore, bacteriocin DF01 can be used in the manufacture of fermented meat products due to its inhibition of tyramine-producing L. curvatus and non-inhibition of L. sake, which is used as a starter culture for meat fermentation.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.96-101
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• 1991

Phenotypic changes after plasmid curing experiment suggested that the bacteriocin production phenotype ($Bac^{+}$) might be linked to a chromosomal DNA and the mucin production phenotype ($Muc^{+}$) might be linked to a 62.5 kilobase (kb) plasmid (pMUC62) in Lactobacillus plantarum 27 isolated from meat starter culture. The non-mucoid ($Muc^{-}$) variants were missing pMUC62 but they produced bacteriocin as the wild strain ($Bac^{+}$). There was no difference in antibiotic resistance and sugar fermentation patterns between the wild strain ($Bac^{+}$ $Muc^{+}$) and the nonmucoid ($Bac^{+}$ $Muc^{-}$) variants. Antimicrobial spectrum of bacteriocin produced by both wild strain and $Muc^{-}$ variant of Lb. plantarum 27 included strains of Pediococcus acidilactici (A, M, H), Pediococcus sp. isolated from meat, Lactobacillus sp. isolated from meat, Lb. plantarum NCDO 955 and Staphylococcus aureus 485. Neither of the tested Gram negative bacteria were inhibited by bacteriocin. Antimicrobial activity of crude bacteriocin was retained after autoclaving, DNase or catalase treatment and exposure from pHs 4 to 9 but was lost after treating with several proteolytic enzymes and exposure at pH 10.

• 한국미생물·생명공학회지
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• 제47권2호
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• pp.201-210
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• 2019

Biotransformation of ginsenosides by microorganisms alters the absorption and bioavailability of ginseng as a medicinal herb. In this study, we isolated two kinds of fermenting microorganisms from Eoyukjang, which is a traditional Korean fermented food made from soybean. Next, we identified and detected their ability to convert major ginsenosides to compound K. The two microorganisms, referred to as R2-6 and R2-15, had 100% similarity with Lactobacillus plantarum subsp. plantarum ATCC $14917^T$ and Lactobacillus rhamnosus JCM $1136^T$, respectively. The optimal pH and growth temperature of the isolates were determined to be pH 6-7 and $30^{\circ}C$. After fermentation for 30 days, the major ginsenosides in the mountain-cultivated ginseng were transformed to the highly bioactive ginsenoside, compound K, in the final product.

• 한국미생물·생명공학회지
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• 제14권6호
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• pp.487-493
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• 1986

L. helveticus YM-1과 Str. lactis ML$_3$를 환원탈지유 배지에 혼합배양시켜 단백질 가수분해 활성과 산발효 촉진물질을 검토하였다. 두 균을 8시간 동안 배양한 결과 단백질 가수분해 활성은 현저한 차이를 나타냈으며, 배양액중의 우유 단백질 가순분해물을 측정하여 tyrosine 양으로 환산했을 때 L.helveticus YM-1은 105$\mu\textrm{g}$/$m{\ell}$, Str. lactis ML$_3$는 30$\mu\textrm{g}$/$m{\ell}$였다. 탈지유에 Str. lactis ML$_3$의 배양여액을 첨가하여 L. helveticus YM-1을 배양했었을 때 L. helveticus YM-1의 산 발효를 거의 촉진시키지 못하였으며, 반대로 L. helveticus YM-1의 배양여액을 첨가하여 Str. laclis ML$_3$을 배양했었을 때는 Str. lactis ML$_3$의 산발효를 크게 촉진시켰다. Str. lactis ML$_3$의 산발효 촉진물로는 L. helveticus YM-1이 우유 단백질을 가수분해하여 생산한 분자량 4300 정도의 peptide이며, 이 peptide를 산으로 가수분해한 결과 lysine, arginine, glutamic acid가 주로 많이 존재하였다. 또한 유리 아미노산으로 탈지유에 첨가하여 Str. lactis ML$_3$를 배양했을 때 여러 아미노산 중에서 histidine, glutamic acid, phenylalanine이 산생성을 가장 촉진하였고 isoleucine은 오히려 저해하였다.

• Journal of Dairy Science and Biotechnology
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• 제33권1호
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• pp.17-25
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• 2015

본 실험은 쌀겨를 발효식품에 이용하고자 상업용 균주인 Streptococcus thermophilus(ST-body1), Lactobacillus casei(LC-10)을 이용하여 발효유를 제조하고, 발효시간 경과에 따라 적정산도, 유산균수, 유기산 측정, 유리아미노산 측정, 관능검사를 측정하였다. ST-body1은 대조구와 처리구 모두 발효 3시간째에 급격하게 산도가 증가하였다. 하지만 LC-10은 산도의 증가폭이 크지 않아 24시간 발효를 하여도 산도가 0.5%를 넘지 못하였다. 균주의 생균수는 대조군과 실험군 모두 배양 24시간 동안 뚜렷한 경향 없이 $10^6{\sim}10^9CFU/mL$ 사이로 존재하였다. 유기산 및 유리아미노산 측정 결과, ST-body1 생장 및 생육에는 glutamic acid가 LC-10 생장 및 생육에는 aspartic acid가 밀접한 관계를 보였으며, LC-10은 발효 시 methionine이 20~30시간 경에 감소하다가 증가하는 것으로 보아 methionine을 발효 시 이용하고, 재생산하는 것으로 추측된다. 관능검사 결과, 선호도는 ST-body1이 미강의 존재 유무에 관계없이 우수하였다.

• 미생물학회지
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• 제50권1호
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• pp.60-66
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• 2014

본 연구에서는 Lactobacillus brevis HLJ59 균주를 이용하여 오미자 당침액의 발효특성을 조사하였다. 발효에 따른 생균수와 PPH radical 소거활성, 환원력 및 SOD 유사활성을 조사하였다. 또한 오미자 당침액의 ACE 저해활성 및 Urease 저해활성을 조사하였다. 생균수의 경우 2배, 5배, 10배 희석액의 경우 $2.05{\pm}0.21{\times}10^8$, $6.31{\pm}0.56{\times}10^{11}$, $8.14{\pm}0.14{\times}10^9$으로 각각 조사되었으며, DPPH radical 소거활성은 2배, 5배, 10배 희석액의 경우 60.3%, 71.8%, 44.5%로 각각 조사되었다. 환원력은 2배, 5배, 10배 희석액의 경우 0.92, 1.19, 0.73 (700 nm에서의 OD값)로 각각 조사되었고, SOD 유사활성은 2배, 5배, 10배 희석액의 경우 50.4%, 53.7%, 33.4%로 각각 조사되었다. 그리고 ACE 저해활성 및 Urease 저해활성은 2배, 5배, 10배 희석액의 경우 47.4%, 78.2%, 56.4% 및 58.1%, 83.4%, 63.2%로 각각 조사되었다. 이상의 결과에서 오미자 당침 희석액 발효물은 우수한 항산화활성과 ACE 및 Urease 저해활성을 지님으로서 이를 기능성 식품소재로 활용할 수 있다고 사료된다.