• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1216-1222
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• 2017

To develop starters for the production of functional foods or materials, lactic acid bacteria producing ${\gamma}-aminobutyric$ acid (GABA) were screened from jeotgals, Korean fermented seafoods. One isolate producing a high amount of GABA from monosodium $\text\tiny{L}$-glutamate (MSG) was identified as Enterococcus avium by 16S rRNA gene sequencing. E. avium M5 produced $18.47{\pm}1.26mg/ml$ GABA when incubated for 48 h at $37^{\circ}C$ in MRS broth with MSG (3% (w/v)). A gadB gene encoding glutamate decarboxylase (GAD) was cloned and overexpressed in E. coli BL21 (DE3) using the pET26b (+) expression vector. Recombinant GAD was purified through a Ni-NTA column and the size was estimated to be 53 kDa by SDS-PAGE. Maximum GAD activity was observed at pH 4.5 and $55^{\circ}C$and the activity was dependent on pyridoxal 5'-phosphate. The $K_m$ and $V_{max}$ values of GAD were $3.26{\pm}0.21mM$ and $0.0120{\pm}0.0001mM/min$, respectively, when MSG was used as a substrate. Enterococcus avium M5 secretes a lot of GABA when grown on MRS with MSG, and the strain is useful for the production of fermented foods containing a high amount of GABA.

• Journal of Microbiology
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• 제40권2호
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• pp.156-160
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• 2002

The whole gal/lae operon genes of Lactococcus lactis ssp. lactis 7962 were reported as follows: galA-galM-galK-galT-lacA -lacZ-galE. The galK gene encoding a galactokinase involved in one of the Leloir pathways for galactose metabolism was found to be 1,197 bp in length and encodes a protein of 43,822 Da calculated molecular mass. The deduced amino acid sequence showed over 50% homology with GaIK proteins from several other lactic acid bacteria. The galK gene was expressed in E. coli and the product was identified as a 43 kDa protein which corresponds to the estimated size from the DNA sequence. The galactokinase activity of recombinant 5. coli was about 8 times greater against that of the host strain and more than 3 times higher than the induced L. lactis 7962.

• KSBB Journal
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• 제10권5호
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• pp.553-560
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• 1995

어린돼지의 분변으로부터 Salmonella paratyphi에 강한 항균활성을 나타내는 균주를 분리하여, 이 균주를 Lactobacillus sp. KJ-5로 동정하였다. Lactoba C cillus sp. KJ-5 배양액의 항균활성은 균주의 성장에 비례하여 증가하여 정지기에서 최대를 나타냈으며, 최적 항균활성을 위한 배양온도는 $37^{\circ}C$로서 균주의 최적 성장온도와 통일하였다. Lactobacillus sp. KJ­5 배양여액의 pH를 6.2로 조정한 경우 항균활성이 약간 감소하였으나, catalase 처리에 의해셔는 항균 활성에 아무런 영향이 없었으므로 배양중에 생성된 산이나 H101 이외의 물질이 항균활성에 관여함을 알 수 있었다. 배양여 액으로 부터 methanol과 acetone 추출에 의하여 S. paratyphi어l 항균활성을 냐타내는 항균물질을 부분정제하였다. 부분정제된 항균물질은 thin-layer chromatography에서 3개의 물질로 분리 되었으며, 이중에 하나가 항균활성을 나타내었다. 또 한 부분정제된 항균물질은 270nm에셔 최대 uv 흉 광도를 나타내였으며, 단백질 가수분해 효소의 처리 에 의하여 완전히 불활성화 되었다. 따라서 Lactob$\alpha$ C cillus sp. KJ-5가 생성하는 항균물질은 저분자량의 단백질일 것으로 추정된다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.287-296
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• 2007

A Lactobacillus paraplantarum strain producing a bacteriocin was isolated from kimchi using the spot-on-the lawn method and named L. paraplantarum C7 [15]. The bacteriocin, paraplantaricin C7, was found to inhibit certain Lactobacillus strains, including L. plantarum, L. pentosus, and L. delbrueckii subsp. lactis. It also inhibited Enterococcus faecalis, yet did not inhibit most of the other LAB (lactic acid bacteria) tested. The maximum level of paraplantaricin C7 activity was observed under the culture conditions of $25^{\circ}C$ and a constant pH of 4.5. Paraplantaricin C7 retained 90% of its activity after 10 min of treatment at $100^{\circ}C$ and remained stable within a pH range of 2-8. Based on a culture supernatant, paraplantaricin C7 was purified by DEAE-Sephacel column chromatography and $C_{18}$ reverse-phase HPLC. SDS-PAGE and activity staining were then conducted using the purified paraplantaricin C7, and its molecular mass determined to be about 3,800 Da. The 28 N-terminal amino acids from the purified paraplantaricin C7 were determined, and the structural gene encoding paraplantaricin C7, ppnC7, was cloned by PCR using degenerate primers based on the N-terminal amino acid sequence. The nucleotide sequences for ppnC7 and other neighboring orfs exhibited a limited homology to the previously reported plantaricin operon genes. Paraplantaricin C7 is a novel type II bacteriocin containing a double glycine leader sequence.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.64-68
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• 2013

Previous studies have shown that lactic acid bacteria can inhibit inflammatory responses, but the mechanisms are very little known. In this study, transaction and expression of three proinflammatory factors, iNOS, PTGS-2, and IL8, which are closely related to the inflammatory response, were investigated by luciferase reporter assay and RTPCR in HT-29 cells treated by Lactobacillus acidophilus. The results showed that the live L. acidophilus sharply down-regulated the transcription of these three genes. Because there was a NF-${\kappa}B$ binding site located at -265 bp, -225 bp, and -95 bp upstream of the iNOS, PTGS-2, and IL8 promoters, respectively, we further addressed the effects of NF-${\kappa}B$ on transaction of the three promoters by cotransfection. As was expected, NF-${\kappa}Bs$ remarkably upregulated the activity of the reporter gene and, no effect of NF-${\kappa}B$s on IL-8 promoter transaction was found after NF-${\kappa}B$ binding site mutation of the IL8 promoter in HT-29 cells. In conclusion, the live L. acidophilus decreased the transcriptional activity of NF-${\kappa}B$ and, in turn, inhibited the transaction of NF-${\kappa}B$ on the three proinflammatory factors mentioned above.

• 한국축산식품학회지
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• 제32권4호
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• pp.404-408
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• 2012

This study was performed to investigate the effects of laying productivity and egg quality according to providing germinated and fermented soybean (GFS) as feed additive. Among the strain, we selected Monascus purpureus KCCM 12002 so that inoculated in soybean and fermented for 48 h at $20^{\circ}C$. A total of two-hundred forty 70-wk-old Hy-Line Brown layers were divided into four groups (4 treatment${\times}$6 replication${\times}$10 birds each) and fed diets containing 0 (as control) (T1), 0.5% (T2), 1.0% (T3) or 2.0% GFS (T4) for 6 wk. The laying productivity, egg quality and blood property in the egg yolk were experimented. There were no significant differences in the laying productivity, relative liver and spleen weights, egg yolk color and eggshell strength among another groups. The eggshell color, eggshell thickness and haugh unit significantly increased in the GFS-supplemented group (p<0.05) compared to control. However, no significant differences were observed in the blood property after supplementation. The amount of lactic acid bacteria present during storage increased by providing of GFS (p<0.05) compare to control group. Our study results suggested that GFS can be used as a favorable feed additive and feedstuff for the productivity of high quality eggs and promoted relative industry.

• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.117-125
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• 2022

Until recently, four types of cellobiose-fermenting Saccharomyces cerevisiae strains have been developed by introduction of a cellobiose metabolic pathway based on either intracellular β-glucosidase (GH1-1) or cellobiose phosphorylase (CBP), along with either an energy-consuming active cellodextrin transporter (CDT-1) or a non-energy-consuming passive cellodextrin facilitator (CDT-2). In this study, the ethanol production performance of two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-2 (N306I) with GH1-1 or CBP were compared with two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-1 (F213L) with GH1-1 or CBP in the simultaneous saccharification and fermentation (SSF) of cellulose under various conditions. It was found that, regardless of the SSF conditions, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the best ethanol production among the four strains. In addition, during SSF contaminated by lactic acid bacteria, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the highest ethanol production and the lowest lactate formation compared with those of other strains, such as the hydrolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-1 with GH1-1, and the glucose-fermenting S. cerevisiae with extracellular β-glucosidase. These results suggest that the cellobiose-fermenting yeast strain exhibiting low energy consumption can enhance the efficiency of the SSF of cellulosic biomass.

• 융합정보논문지
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• 제11권5호
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• pp.223-231
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• 2021

유산균에 의한 감국 추출물(CIL)의 항산화능의 변화를 알아보기 위해 64%, 80% ethanol 로 추출한 농도별 CIL를 발효시켜 total phenolic contents (TPC), flavonoid, 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power (RP), linoleic acid 자동산화 저해활성의 변화를 확인해 보았다. TPC의 경우 3109, 3237에서 증가하였으며, flavonoid에서는 모든 균주에서 감소를 나타냈다. DPPH 측정에서는 64% CIL 발효 후 3074, 3109에서 증가하였으며, 80% CIL 발효에서는 모든 균주가 증가를 나타냈다. RP측정에서는 64%, 80% CIL에서 모든 균주에서 증가를 보였으며, linoleic acid 자동산화 저해활성에서는 모든 균주에서 감소를 나타냈다. 특히 3109 항산화능을 평가하는 DPPH와 RP 측정에서 다른 균주에 비해 전반적으로 높게 측정이 되었다. 결과적으로 4종의 유산균 중에서 3109가 발효과정을 통해서 CIL의 항산화 효능을 효과적으로 증대하는 것을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제34권2호
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• pp.358-366
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• 2024

The lactic acid bacteria, including Latilactobacillus sakei and Latilactobacillus curvatus, have been widely studied for their preventive and therapeutic effects. In this study, the underlying mechanism of action for the antioxidant and immunostimulatory effects of two strains of heat-treated paraprobiotics was examined. Heat-treated L. sakei KU15041 and L. curvatus KU15003 showed higher radical scavenging activity in both the 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assays than the commercial probiotic strain LGG. In addition, treatment with these two strains exhibited immunostimulatory effects in RAW 264.7 macrophages, with L. curvatus KU15003 showing a slightly higher effect. Additionally, they promoted phagocytosis and NO production in RAW 264.7 cells without any cytotoxicity. Moreover, the expression of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 was upregulated. These strains resulted in an increased expression of inducible nitric oxide synthase and cyclooxygenase-2. Moreover, the nuclear factor-κB and mitogen-activated protein kinase signaling pathways were stimulated by these strains. These findings suggest the potential of using L. sakei KU15041 and L. curvatus KU15003 in food or by themselves as probiotics with antioxidant and immune-enhancing properties.

• 한국식품영양과학회지
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• 제45권3호
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• pp.386-395
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• 2016

본 연구는 복분자와 클로렐라 혼합물의 기능성 발효제품을 개발하고자 품질 특성을 최대화할 수 있는 최적 발효조건을 확립하고, 확립된 방법으로 제조한 혼합 발효물의 일반성분, 유리당, 유기산, 항균 활성 등 화학적 특성에 대한 품질 특성을 조사하였다. 먼저 복분자와 클로렐라 젖산발효 혼합물의 최적 발효균주를 확인한 결과 젖산 생성이 Lactobacillus plantarum에서 가장 우수한 것으로 평가되었고, 최적 발효 온도는 $37^{\circ}C$였다. 이와 같은 조건으로 복분자와 클로렐라 젖산발효 혼합물을 제조하여 관능평가를 한 결과 종합적 기호도 측면에서 클로렐라 분말 5% 첨가구가 가장 우수한 것으로 평가되었다. 따라서 시판 복분자 착즙액(Rubus coreanus Miquel juice; RCM)과 복분자와 클로렐라 5% 첨가 젖산발효 혼합물(RCM-C5)을 제조하여 일반성분, 유리당, 유기산, 항균 활성 등 품질 특성을 조사하였다. RCM과 비교하여 RCM-C5는 수분의 경우 4.90%, 건량 기준 총당은 14.15%, 건량 기준 조섬유는 0.32% 감소하였다. 한편 건량 기준으로 조단백질, 조지방, 조회분은 각각 13.75%, 0.18%, 0.73% 증가하였다. 색도는 두 시료 모두 밝고 약간의 황색을 띠는 적색이었지만 RCM-C5가 RCM보다 황색을 더 띠었다. RCM과 비교하여 RCM-C5의 유리당 함량은 0.97%, 유기산 함량은 616.30 mg%, 항균 활성은 그람양성균인 Staphylococcus aureus가 5.83%, 그람음성균인 Escherichia coil와 Salmonella Typhimurium은 각각 2.94%, 4.67% 증가하였다. 이상의 결과로 미루어본바 일반 복분자 시제품보다 복분자와 클로렐라 젖산발효 혼합물의 품질 특성이 향상되는 결과를 나타내어, 이를 실제 제품으로 제조한다면 영양 기능성이 풍부한 기능성 발효식품으로 활용이 가능할 것으로 판단된다.