• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1500-1509
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• 2020

Drought is a major abiotic factor and has drastically reduced crop yield globally, thus damaging the agricultural industry. Drought stress decreases crop productivity by negatively affecting crop morphological, physiological, and biochemical factors. The use of drought tolerant bacteria improves agricultural productivity by counteracting the negative effects of drought stress on crops. In this study, we isolated bacteria from the rhizosphere of broccoli field located in Daehaw-myeon, Republic of Korea. Sixty bacterial isolates were screened for their growth-promoting capacity, in vitro abscisic acid (ABA), and sugar production activities. Among these, bacterial isolates YNA59 was selected based on their plant growth-promoting bacteria traits, ABA, and sugar production activities. Isolate YNA59 highly tolerated oxidative stress, including hydrogen peroxide (H₂O₂) and produces superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in the culture broth. YNA59 treatment on broccoli significantly enhanced plant growth attributes, chlorophyll content, and moisture content under drought stress conditions. Under drought stress, the endogenous levels of ABA, jasmonic acid (JA), and salicylic acid (SA) increased; however, inoculation of YNA59 markedly reduced ABA (877 ± 22 ng/g) and JA (169.36 ± 20.74 ng/g) content, while it enhanced SA levels (176.55 ± 9.58 ng/g). Antioxidant analysis showed that the bacterial isolate YNA59 inoculated into broccoli plants contained significantly higher levels of SOD, CAT, and APX, with a decrease in GPX levels. The bacterial isolate YNA59 was therefore identified as Variovorax sp. YNA59. Our current findings suggest that newly isolated drought tolerant rhizospheric Variovorax sp. YNA59 is a useful stress-evading rhizobacterium that improved drought-stress tolerance of broccoli and could be used as a bio-fertilizer under drought conditions.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.497-502
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• 2002

Thirty-nine strains of Leuconostocs found to be tolerant to $10\%$ or more garlic were selected for further identification, by comparing their whole-cell protein pattern, 16S rRNA gene (first 530 bases) sequence, cellular fatty acid composition, and carbon source metabolism. Two isolates were Identified as Leuconostoc mesenteroides and 32 others as Leuconostoc citreum. Five other strains belonging to a cluster could not be allocated to the existing species. 16S rRNA gene sequence and cellular fatty acid composition of the unidentified bacteria exhibited close similarity with Leuconostoc argentinum. The unidentified isolates were not allocated to L. argentinum, because they formed polysaccharide from sucrose, while L. argentinum strains do not. Leuconostocs tolerant to high concentration of garlic were found predominantly on garlic surface, an extreme environment which is unfit for most of other microorganisms.

• 한국식품위생안전성학회지
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• 제1권2호
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• pp.133-141
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• 1986

주요 농산 건조가공품에 오염된 미생물의 효과적인 살균법 개발을 목적으로, 현행방법인 ethylene oxide 훈증처리와 감마선 조사에 따른 미생물의 살균효과와 이화학적 품질에 미치는 영향을 검토한 결과는 다음과 같다. 시료의 미생물 오염도는 고추장 분말, 참깨, 느타리버섯 분말, 당근 flake의 순이었으며, 전세균이 $4.6{\times}10^{3}/g~1.5{\times}10^{6}/g$, 내열성 세균이 $1.3{\times}10^{3}/g~1.4{\times}10^{6}/g$, 산저항성 세균이 $8.4{\times}10^{2}.g~8.8{\times}10^{5}/g$, 내삼투압성 곰팡이를 포함한 곰팡이류는 $4.0{\times}10^{2}/g~1.5{\times}104/g$, 대장균군은 당근 flake를 제외한 나머지 시료에서 $4.0{\times}10^{3}/g~2.7{\times}10^{5}/g$ 정도로 오염되어 있어 위생적인 살균처리가 요구된다. 살균효과 실험에서는 대부분의 시료가 7~10 kGy의 감마선 조사로서 모든 미생물의 사멸이 가능하였으나 ethylene oxide 처리구에서는 전반적으로 전세균과 내열성 포자균 및 곰팡이의 살균이 불충분하였다. Ethylene oxide 처리는 시료의 색소, 아미노산, 무기질, 색도 등에 상당한 영향을 미쳤으나 적정선량의 감마선 조사는 이들에 대해 비교적 안전하였으며, 실온에서 3개월 동안 저장된 시료의 전반적인 기호도는 감마선 조사구가 ethylene oxide 처리구나 대조구보다 우수하게 나타났다.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.506-513
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• 1999

유기게르마늄(Ge-132, carboxyethylgermanium)에 의한 22가지 젖산균의 성장 효과를 0.01~10mg/m1의 농도로 첨가된 GPYS 액체배지에서 조사하였다. 시험한 대부분의 젖산균은 고농도의 게르마늄에서도 내성이 있었고, 게르마늄의 농도가 높을수록 성장을 더욱 촉진시키는 효과가 나타났다. 게르마늄이 10mg/m1의 농도로 첨가된 GPYS배지에서 Lactococcus factis, Lc. cremoris, Lc. diacetilactis, Enterococus faecium 및 Streptococcus faecalis는 2배 이상 생육촉진의 효과를 나타내었으나, Leuconostoc mesenteroides와 Pediococcus pentosareus는 저해를 나타내었다. Lc. lactic와 Lc. cremoris의 경우, 배양액의 점도는 게르마늄이 첨가된 GPYS배지에서 급격히 증가되었지만, 장시간 배양에 의해서는 약간 감소되었다. 그러나 Lc. diacetilactis, E. faecium와 S. faecalis의 경우, 게르마늄의 첨가에 의하여 생육은 현저하게 촉진되었지만, 배양중의 점도는 증가되지 않았다.

• 한국식품영양과학회지
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• 제15권1호
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• pp.69-74
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• 1986

Lactobacillus plantarum을 이용하여 햄의 품질과 풍미를 개선하고 염지 기간을 단축하기 위하여 공시균을 육내부에 접종한 후 염지 기간별로 세균수의 변화 및 이화학적 변화를 조사한 결과는 아래와 같다. 1. 염지 경과에 따른 염지육에 있어서의 대장균군은 기간이 지남에 따라 감소하는 경향이었고 저온균과 내염균은 4일까지 증가한후 다소 감소하였다. 2. 염지 경과에 따른 염지액에 있어서의 대장균군은 4일까지 증가한후 감소하였고 저온균 및 내염균은 7일가지 증가한후 감소하는 경향이었다. 3. pH의 변화는 염지육과 염지액에서 다같이 1일째 급속히 저하한후 서서히 증가하는 경향이었다. 4. 염지 육색은 7일째 84.05%의 발색율을 나타내어 가장 높았다. 5. 아미노산 조성은 17종의 아미노산중 7일과 10일째에 glutamic acid함량이 14.76%과 14.01%로 가장 높았다. 6. 지방산의 조성은 13종이며 전체 불포화 지방산은 서서히 감소하는 경향이었다.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• Journal of Animal Science and Technology
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• 제58권7호
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• pp.26.1-26.11
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• 2016

The use of probiotics for human and animal health is continuously increasing. The probiotics used in humans commonly come from dairy foods, whereas the sources of probiotics used in animals are often the animals' own digestive tracts. Increasingly, probiotics from sources other than milk products are being selected for use in people who are lactose intolerant. These sources are non-dairy fermented foods and beverages, non-dairy and non-fermented foods such as fresh fruits and vegetables, feces of breast-fed infants and human breast milk. The probiotics that are used in both humans and animals are selected in stages; after the initial isolation of the appropriate culture medium, the probiotics must meet important qualifications, including being non-pathogenic acid and bile-tolerant strains that possess the ability to act against pathogens in the gastrointestinal tract and the safety-enhancing property of not being able to transfer any antibiotic resistance genes to other bacteria. The final stages of selection involve the accurate identification of the probiotic species.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1680-1685
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• 2003

Antimutagenicity of milk cultured with lactic acid bacteria isolated from dadih on the mutagenicity of heated salty and sweet tauco was examined using streptomycin dependent (SD) 510 strain of Salmonella typhimurium TA 98 as a tester culture. Cultured milk samples exhibited widely antimutagenic activity against mutagenic heated salty and sweet tauco. Lc. lactis subsp. lactis R-22, Lc. lactis subsp. casei R-35, Lc. lactis subsp. casei R-52 and E. faecalis subsp. liquefaciens R-55 exhibited no inhibitory effect on the mutagenic heated salty tauco. Mutagenicity of heated sweet tauco was inhibited by cultured milks stronger than that of heated salty tauco. Milk cultured with Lc. lactis subsp. cremoris R-48, Leuc. mesentroides R-51 and Lc. lactis subsp. casei R-68 showed high inhibition against the mutagenicity of both heated salty and sweet taucos. Antimutagenic activity of the cultured milks against mutagenic heated tauco was attributed to the bacterial cells. Among the three strains which showed high antimutagenicity, only Leuc. mesentroides R-51 was tolerant to both acid and bile; so this strain can be used as probiotic in preventing the occurrence of mutagenesis caused by mutagenic heated food like tauco.

• 한국환경농학회지
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• 제13권3호
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• pp.311-320
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• 1994

농축산(農畜産) 폐기물(廢棄物)의 혐기적(嫌氣的) 처리공정(處理工程)에 적용하기 위하여 아한대(亞寒帶) 지역(地域)으로 부터 분리(分離)한 clostridia의 생화학적(生化學的) 특성(特性)을 조사(調査)한 결과(結果)는 다음과 같았다. 1. Cellulose 배지로 저온(低溫)에 집적배양(培養)한 결과 $CH_4$ 생성이 왕성(旺盛) 하였던 늪지 퇴적물(堆積物)(Canada, $56.9^{\circ}N$), 호수퇴적물(堆積物) Ⅳ(Canada, $55.0^{\circ}N$) 그리고 갯벌흙 Ⅱ(Korea, $37.0^{\circ}N$)에서 산생성능(酸生成能)이 우수하고 동시에 메탄을 생성하는 Clostridia, 즉 Clostridium botulinum SRC-64, Clostridium scatologens SRC-91 및 Clostridium tyrobutyricum SRC-100 을 각각 분리(分離)하였다. 분리(分離)된 clostridia 3균주(菌株)의 최적(最適) 생육온도(生育溫度)는 $37^{\circ}C$이었고 최저(最低) 생육온도(生育溫度)는 $10^{\circ}C$ 정도 이었으며, 그리고 이들 균주(菌株)는 특이적 메탄 생성균(生成菌)의 조효소(組酵素)인 $F_{420}$을 함유 하였다. 2. 포도당의 혐기분해(嫌氣分解) 생성물(生成物)로서 SRC-64 는 $H_2$, acetic, isovaleric, caproic acid 를 생성(生成)하였으며, SRC-91 은 $H_2$, propionic, butyric, valeric, caproic acid 를, SRC-100 은 acetic 과 propionic acid 를 주로 생성(生成) 하였다. 또한 3 균주(菌株) 모두 $13^{\circ}C$, 2 일(日) 배양조건(培養條件)에서 2.6-8.68 n moles/ml 범위(範圍)의 $CH_4$ 생성능력(生成能力)을 나타냈다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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• pp.726-731
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• 2003

The aim of this research was to identify candidate probiotic lactic bacteria among indigenous dadih lactic isolates. Dadih is an Indonesian traditional fermented milk of West Sumatra which is fermented naturally. Viability of the strain is critical in determining the capacity of lactic bacteria to induce immune stimulation as well as to colonize in the intestinal tract. Therefore, LAB are proposed to exert health promoting or probiotic effects in human, such as inhibition of pathogenic microflora, antimutagenic, and the reduction of cholesterol levels. This manuscript reports in vitro probiotic properties of indigenous dadih lactic bacteria, especially some important colonization factors in GI tract, such as lysozyme, acid and bile tolerance. Bile Salt Hydrolase (BSH) activity, spectrum of bacteriocin, and antimutagenic activity of bacterial cells were also assessed. Twenty dadih lactic isolates were screened further for their tolerance to low pH, at pH 2 and 3 as well as their bile tolerance. There were ten isolates classified as acid and bile acid tolerant, and further screened for lysozyme tolerance, BSH activity. The spectrum of bacteriocin activity of isolates was assayed using cell-free neutralized supernatants by agar spot test against variety of pathogens. Lc. lactis subsp. lactis IS-10285, IS-7386, IS-16183, IS-11857 and IS-29862, L. brevis IS-27560, IS-26958 and IS-23427, Leu.mesen.mesenteroides IS-27526, and L. casei IS-7257 each has good survival rate at low pH values and in the presence of lysozyme, and short lag time in the presence of 0.3 % oxgall. Lc. lactis subsp. lactis IS-11857 and IS-29862 each has high BHS activity, Lc. lactis subsp. lactis IS-10285 and IS-16183 each had a positive spectrum of bacteriocin activity against E. coli 3301 and Lysteria monocytogenes ATCC 19112, while L. brevis IS-26958 has high BHS activity as well as positive spectrum of bacteriocin against E. coli 3301, Lysteria monocytogenes ATCC 19112, and S. aureus IFO 3060. All of the ten dadih lactic strains performed in vitro acid and bile tolerance, indicating a possibility to reach the intestine alive, and display probiotic activities.