• 한국축산식품학회지
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• 제33권3호
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• pp.335-340
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• 2013

This study screened for radio-resistant strains lactic acid bacteria (LAB) by evaluating their capability to survive exposure to ionizing radiation. Ten strains of LAB - Lactobacillus bulgaricus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pediocuccos pentosaceus - were selected and subcultuted twice. The LAB was then further cultured for 3 d at $37^{\circ}C$ to reach 7-10 Log colony-forming units (CFU)/mL prior to irradiation and immediately exposed to gamma rays or electron beams with absorbed doses of 0, 1, 2, 3, 4, 5, 6, 8, and 10 kGy. Gamma irradiation gradually decreased the number of the tested viable LAB, and the effect was irradiation dose dependent. A similar effect was found in electron beam-irradiated LAB. Radiation sensitivity of LAB was calculated as $D_{10}$ values, which ranged from 0.26 kGy to 0.9 kGy and 0.5 kGy to 1.44 kGy with exposure to gamma and electron beam irradiation, respectively, in all tested LAB. L. acidophilus was the most resistant to gamma and electron beam irradiation, with $D_{10}$ values of 0.9 kGy and 1.44 kGy, respectively. These results suggest that L. acidophilus might be suitable for the preparation of probiotics as direct-fed microbes for astronauts in extreme space environments.

• 대한수의학회지
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• 제20권2호
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• pp.113-118
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• 1980

Total of 11 strains of Ldctobacillus isolated from lactobacillus-fermented milk and-beverage in March 1980 were examined for susceptibility to 8 drugs, and transferability and transfer frequency of R plasmids by conjugation. Of 11 isolates each 2 strains were classified as L. cellobiosus and L. helveticus, each 1 strain as L. plantarum, L. lactis, L. acidophilus, L. delbrueckii, L. casei subsp. casei, L. casei subsp, tolerans and L. salivarius subsp, salivarius by Bergey's manual. Resistance was the most active to na lidixic acid(NA), followed in decreasing order by chloramphenicol(CP), ampicillin(AP), kanamycin(KM) and streptomycin(SM). All of isolates were resistant to NA, each 10 strains to CP and AP, 7strains to KM and 6 strains to SM, indicating all of the isolates were resistant to two or more drugs in combination. No strain was resistant to erythromycin(EM), penicillin(PC) and tetracycline(TC). The most frequently encountered resistant patterns were CP NA AP SM KM, followed by CP NA AP KM, NA AP, CP NA, CP NA AP and CP NA AP SM in order. Transfer experiment of drug resistance showed that of 11 resistant strains, 9 strains transferred parts of their resistance to AP or AP CP or SM AP, indicating 9 strains carried R plasmids determining R(AP), R(AP CP) and R(SM AP). The conjugal frequency of R(AP) from Lactobacillus to E. coli ranged from 2.5{\times}10^{-1} to $5.6{\times}10^{-4}%$, that of R(CP) ranged from 5.0{\times}10^{-1} to 5.0{\times}10^{-3}% and that of R(SM) ranged from 6.0{\times}10^{-5} to 1.4{\times}10^{-5}%, at $37^{\circ}C$ for 18 hours of incubation.

• Journal of Applied Biological Chemistry
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• 제62권4호
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• pp.441-446
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• 2019

The assortment of endophytic lactic acid bacteria (LAB) in kimchi derives from its raw vegetables, which include Chinese cabbage, radish, welsh onion, onion, garlic, red pepper, and ginger. These vegetables were examined during mulkimchi fermentation using gene-specific multiplex polymerase chain reaction and 16S ribosomal RNA sequence analysis. Sixteen species from five LAB genera (Leuconostoc, Lactobacillus, Lactococcus, Pediococcus, and Weissella) appeared in the raw kimchi materials. Interestingly, nine LAB species were identified in mulkimchi on fermentation day 0 as follows: Leuconostoc carnosum, Leuconostoc citreum, Leuconostoc gelidum, Leuconostoc inhae, Leuconostoc mesenteroides, Lactobacillus plantarum, Lactobacillus sakei, Lactococcus lactis, and Weissella confusa. Seven additional LAB species were present in mulkimchi at fermentation day 9 as follows: Leuconostoc gasicomitatum, Leuconostoc kimchii, Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus pentosus, Pediococcus pentosaceus, and Weissella koreensis. These species corresponded completely with the LAB in kimchi vegetables. Wei. confusa was the predominant LAB during early fermentation (pH 6.20 to 4.98 and acidity 0.20 to 0.64%), while Lac. sakei, Lac. plantarum, and Wei. koreensis became dominant later in fermentation (pH 4.98 to 3.88 and acidity 0.64 to 1.26%). These results collectively demonstrate that the LAB involved in mulkimchi fermentation originates from the raw vegetables examined.

• 한국축산식품학회지
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• 제36권1호
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• pp.37-43
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• 2016

Cardiovascular and cerebrovascular diseases seriously harm human health, and Bifidobacterium is the most beneficial probiotic in the gastrointestinal tract of humans. This work aimed to screen cholesterol-lowering Bifidobacterium from Guizhou Xiang Pig and evaluate its tolerance to oxygen, acid, and bile. Twenty-seven aerotolerant strains with similar colony to Bifidobacterium were isolated through incubation at 37℃ in 20% (v/v) CO₂-80% (v/v) atmospheric air by using Mupirocin lithium modified MRS agar medium, modified PTYG with added CaCO₃, and modified PTYG supplemented with X-gal. Ten strains with cholesterol-lowering rates above 20% (w/w) were used for further screening. The selected strains’ tolerance to acid and bile was then determined. A combination of colony and cell morphology, physiological, and biochemical experiments, as well as 16S rRNA gene-sequence analysis, was performed. Results suggested that BZ25 with excellent characteristics of high cholesterol-removal rate of 36.32% (w/w), as well as tolerance to acid and bile, was identified as Bifidobacterium animalis subsp. lactis. To further evaluate Bifidobacterium BZ25’s growth characteristic and tolerance to oxygen, culture experiments were performed in liquid medium and an agar plate. Findings suggested that BZ25 grew well both in environmental 20% (v/v) CO₂-80% (v/v) atmospheric air and in 100% atmospheric air because BZ25 reached an absorbance of 1.185 at 600 nm in 100% atmospheric air. Moreover, BZ25 was aerotolerant and can grow in an agar medium under the environmental condition of 100% atmospheric air. This study can lay a preliminary foundation for the potential industrial applications of BZ25.

• KSBB Journal
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• 제17권6호
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• pp.566-570
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• 2002

Lactococcus lactis IO-1를 이용하여 xylose로부터 젖산발효를 수행한 결과 기질농도가 50 g/L에서 100 g/L로 증가됨에 따라 생육저해 및 생산성감소가 일어났다. 따라서 이온교환수지(Amberlite IRA-400, 250 g)를 이용하여 젖산을 발효 중에 제거함으로 최종산물저해를 완화시킬 수 있는 추출발효를 수행하였다. 초기 xylose 100 g/L에서 발효조내 젖산농도 20 g/L 에서 추출발효를 시작한 결과 기질을 거의 모두 소비하여 총53.6 g/L의 젖산을 생산하였으며 1.6 g/L·h의 생산성을 나타냈다. 이는 일반적인 회분발효에 비해 약 1.8배 향상된 결과로써 향후 수지에 젖간의 흡착을 저해하는 문제점을 개선함으로써 이온교환수지의 젖산 흡착량을 늘릴 수 있는 방안을 모색한다면 지금 보다 더 나은 생산성을 나타낼 것으로 사료된다.

• 한국식품과학회지
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• 제29권5호
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• pp.1063-1066
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• 1997

김치에서 분리한 Leuconostoc속 4종 34주를 RAPD-PCR방법으로 분석하여 기존의 동정 결과를 비교 검토하였다. 상사도 0.5이상의 수준에서 L. mesenteroides subsp. mesenteroides 및 L. mesenteroides subsp. dextranicum균주들은 각 각 3 및 2의 cluster를 형성하였고 L. paramesenteroides 및 L. lactis는 각 각 하나의 cluster를 형성하였다. 각 각의 표준 균주들도 같은 종 혹은 아종의 cluster에 속하는 것으로 나타났다. 그러나 a 및 b cluster의 상사도는 0.2 이하의 수준이며 c cluster는 이들과 상사도가 더욱 낮아 L. mesenteroides subsp. mesenteroides 균주들은 유전적 상사도가 낮은 다양한 종류의 집단임을 추정 할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.469-478
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• 2015

In spite of the reported probiotic effects, Bifidobacterium bifidum BGN4 (BGN4) showed no βglucosidase activity and failed to biotransform isoflavone glucosides into the more bioactive aglycones during soy milk fermentation. To develop an isoflavone-biotransforming BGN4, we constructed the recombinant B. bifidum BGN4 strain (B919G) by cloning the structural β-glucosidase gene from B. lactis AD011 (AD011) using the expression vector with the constitutively active promoter 919 from BGN4. As a result, B919G highly expressed β-glucosidase and showed higher β-glucosidase activity and heat stability than the source strain of the β-glucosidase gene, AD011. The biotransformation of daidzin and genistin compounds using the crude enzyme extract from B919G was completed within 4 h, and the bioconversion of daidzin and genistin in soy milk during fermentation with B919G also occurred within 6 h, which was much faster and higher than with AD011. The incorporation of this β-glucosidase-producing Bifidobacterium strain in soy milk could lead to the production of fermented soy milk with an elevated amount of bioavailable forms of isoflavones as well as to the indigenous probiotic effects of the Bifidobacterium strain.

• 한국식품과학회지
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• 제35권4호
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• pp.743-747
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• 2003

소금의 종류에 따른 유산균 생육저해 효과를 보면, 김치초기 생육균인 W. confusa가 3.0%의 저염소금, 제재염에서 5시간의 유도기 후 급격히 증식했으나 3.0%의 천일염, 죽염첨가시 유도기간이 12시간으로 늘어나 이 소금들에 의해 생육이 약간 저해됨을 알 수 있었다. 중기 생육균인 Lactobacillus delbruekii ss lactis나 Lactobacillus pentosus와 말기 생육균인 L. hamsteri는 3.0%의 사용된 소금 모두에서 12시간의 유도기 후 증식이 확인되었다. 소금 농도를 달리하여 배지에 첨가했을 때 저염소금인 농도를 3.0%, 5.0%로 증가시킨 경우 W. confusa를 제외한 다른 균들의 유도기는 12시간으로 늘어났고 이 효과는 5.0%에서 더 컸다. 천일염, 죽염, 재제염도 같은 경향으로 농도가 커질수록 생육저해 효과가 뚜렷했으며 김치 초기 생육균 W. confusa보다는 후기생육균인 L. hamsteri가 소금에 의한 생육저해효과가 커서 5.0% 천일염, 죽염, 재제염에서는 24시간까지 증식이 억제된 것을 볼 수 있었다.

• Food Science and Biotechnology
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• 제16권1호
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• pp.83-89
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• 2007

In our study, lactic acid bacteria (LAB)-fermented whey solutions were applied in the soybean soaking process to minimize bacterial contamination and to enrich the biologically functional components of isoflavone and $\gamma$-aminobutyric acid (GABA). Among the 11 LAB tested, Bifidobacteria infantis and a mixed culture (Lactobacillus acidophilus, Bifidobacteria lactis, and Streptococcus thermophilus; ABT-3) displaying the greatest $\beta$-glucosidase activity were selected to produce improved biologically functional soybean preparations. In the soybean soaking processing (without water spraying), the LAB-cultured 10% whey solution was used to soak and to ferment the soybeans and the fermented soybeans were finally dried by heat-blowing at $55^{\circ}C$. The processing conditions used in this study demonstrated that the final soybean product had a reduced contamination by aerobic and coliform bacteria, compared to raw soybeans, likely due to the decrease in pH during LAB fermentation. The aglycone content of the isoflavone increased up to 44.6 mg per 100 g of dried soybean by the processing method, or approximately 8-9 times as much as their initial content. The GABA contents in the processed samples increased as the processing time of soaking-fermentation proceeded as well. The soybean sample that fermented by ABT-3 culture for 24 hr showed the greatest increase in GABA content (23.95 to 97.79 mg/100 g), probably as a result of the activity of glutamate decarboxylases (GAD) released from the soybean or produced by LAB during the soaking process.

• 한국한의학연구원논문집
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• 제17권3호
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• pp.115-121
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• 2011

Objective : The purpose of this study was to investigate the changes in the contents of constituents in Socheongryong-tang (CY) and its fermentations (FCY) with 10 species of lactic acid bacteria. Methods : Ten strains of lactic acid bacteria, Lactobacillus casei 127, L. acidophilus 128, L. casei 129, L. plantarum 144, L. amylophilus 161, L. curvatus 166, L. delbruekil subsp. lactis 442, L. casei 693, B. breve 744, and B. thermophilum 748, were used for the fermentation of Socheongryong-tang. The increased and decreased constituents were identified using HPLC/DAD and various liquid chromatographic techniques, and the structure was elucidated using NMR and MS. These compounds were quantitatively analyzed using an HPLC/DAD system. Results : The increased constituents were identified to be liquiritigenin (1) and cinnamyl alcohol (2), and the decreased constituent was determined to be liquiritin (3). Liquiritigenin (1) and cinnamyl alcohol (2) were increased in all of the FCYs, while liquiritin (3) was decreased. The fermentation of the ten lactic acid bacteria demonstrated that the decomposable rate of these three compounds in FCYs were different. Socheongryong-tang fermented by L. plantarum 144 and L. amylophilus 161 showed the most remarkable changes. Conclusions : CY could be increased antibacterial, neuroprotective, or antiinflammatory effect by fermentation with lactic acid bacteria, especially with L. plantarum and L. amylophilus, considering their known biological activities. In addition, it is expected that this study will help to establish quality control parameters for FCY.