• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1033-1042
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• 2019

Bacillus velezensis BS2 was isolated from meongge (common sea squirt) jeotgal, a Korean fermented seafood, and produces a bacteriocin, BacBS2, which strongly inhibits Listeria monocytogenes and Bacillus cereus. BacBS2 was partially purified by Q-Sepharose column chromatography after ammonium sulfate precipitation of the culture supernatant, then further purified by Sephadex G-50 column chromatography. Partially purified BacBS2 was estimated to be 6.5 kDa in size by Tricine-SDS PAGE and activity detection by gel-overlay. Enzyme treatment and FT-IR spectrum of partially purified BacBS2 confirmed its proteinaceous nature. BacBS2 was fully stable at pH 4-9, and half of activity was retained at pH 1-3. Full activity was retained after exposure to $80^{\circ}C$ for 15 min, but half of the activity was retained upon exposure to $90^{\circ}C$ for 15 min or $100^{\circ}C$for 10 min. BacBS2 inhibited L. monocytogenes by bactericidal mode of action. B. velezensis BS2 and its BacBS2 seem useful as biopreservatives for fermented foods such as jeotgal.

• 미생물학회지
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• 제53권4호
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• pp.342-343
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• 2017

토마토 뿌리에서 분리한 Bacillus velezensis T20E-257 균주는 식물촉진효과가 있었고, 본 연구에서 T20E-257 균주의 유전체 서열을 해독하였다. 유전체 초안에서 포함된 2개 contig는 총 염기서열이 3,900,066 bp고, G + C content가 46.7%이었다. 유전체에서 단백질 유전자 3,708개, rRNA 유전자 27개, tRNA 유전자 86개를 확인하였다. 항균활성을 가지는 2차 대사산물 생합성 관련 유전자군과 식물생육촉진에 관여하는 IAA와 2,3-butadiol 생합성 관련 유전자를 T20E- 257 균주 유전체에서 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.347-356
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• 2019

Bacillus sp. BS2 showing strong fibrinolytic activity was isolated from sea squirt (munggae) jeotgal, a traditional Korean fermented seafood. BS2 was identified as B. velezensis by molecular biological methods. B. velezensis BS2 grows well at 15% NaCl and at $10^{\circ}C$. When B. velezensis BS2 was cultivated in TSB broth for 96 h at $37^{\circ}C$, the culture showed the highest fibrinolytic activity ($131.15mU/{\mu}l$) at 96 h. Three bands of 27, 35 and 60 kDa were observed from culture supernatant by SDS-PAGE, and fibrin zymography showed that the major fibrinolytic protein was the 27 kDa band. The gene (aprEBS2) encoding the major fibrinolytic protein was cloned, and overexpressed in heterologous hosts, B. subtilis WB600 and E. coli BL21 (DE3). B. subtilis transformant showed 1.5-fold higher fibrinolytic activity than B. velezensis BS2. Overproduced AprEBS2 in E. coli was purified by affinity chromatography. The optimum pH and temperature were pH 8.0 and $37^{\circ}C$, respectively. $K_m$ and $V_{max}$ were 0.15 mM and $39.68{\mu}M/l/min$, respectively, when N-succinyl-Ala-Ala-Pro-Phe-pNA was used as the substrate. AprEBS2 has strong ${\alpha}$-fibrinogenase and moderate ${\beta}$-fibrinogenase activity. Considering its high fibrinolytic activity, significant salt tolerance, and ability to grow at $10^{\circ}C$, B. velezensis BS2 can be used as a starter for jeotgal.

• Journal of Microbiology and Biotechnology
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• 제19권5호
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• pp.520-524
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• 2009

Two isolates, Bacillus sp. BS87 and RK1, selected from soil in strawberry fields in Korea, showed high levels of antagonism towards Fusarium oxysporum f. sp. fragariae in vitro. The isolates were identified as B. velezensis based on the homology of their gyrA sequences to reference strains. BS87 and RK1 were evaluated for control of Fusarium wilt in strawberries in pot trials and field trials conducted in Nonsan, Korea. In the pot trials, the optimum applied concentration of BS87 and RK1 for pre-plant root-dip application to control Fusarium wilt was $10^5$ and $10^6$ colony-forming units (CFU)/ml, respectively. Meanwhile, in the 2003 and 2005 field trials, the biological control efficacies of formulations of RK1 were similar to that of a conventional fungicide (copper hydroxide) when compared with a non-treated control. The RK1 formulation was also more effective than BS87 in suppressing Fusarium wilt under field conditions. Therefore, the results indicated that formulations of B. velezensis BS87 and RK1 may have potential to control Fusarium wilt in strawberries.

• The Plant Pathology Journal
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• 제37권3호
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• pp.307-314
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• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• 한국미생물·생명공학회지
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• 제47권3호
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• pp.359-363
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• 2019

국내 5개 지역에서 수집한 12개 메주로부터 Bacillus, Enterococcus, Staphylococcus 속 bacteria를 선택배지를 이용하여 분리하고, 16S ribosomal RNA 유전자 및 gmk(guanylate kinase) 유전자 염기서열분석을 통해 동정하여, 이들 속의 우점종을 검토하였다. Bacillus 속과 Enterococcus 속은 모든 시료로부터 검출되었고, Bacillus 속은 11개 시료에서 총균수 대비 15% 이상 검출되어 메주 발효에서 가장 우점하는 bacteria로 확인되었다. Staphylococcus 속은 6개 시료에서만 검출되었다. Bacillus 속으로 동정된 151개 분리주는 B. velezensis, B. sonorensis 순으로 우점하였고, B. subtilis, B. licheniformis가 그 뒤를 이었다. Enterococcus 속으로 동정된 165개 분리주 중, 163균주가 E. faecium으로 확인되었다. Staphylococcus 속으로 동정된 82개 분리주에는 6종의 coagulase-negative Staphylococcus 존재가 확인되었고, S. xylosus가 우점종으로 확인되었다.

• The Plant Pathology Journal
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• 제37권6호
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• pp.580-595
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• 2021

Although late blight is an important disease in ecofriendly potato cultivation in Korea, it is highly dependent on the use of eco-friendly agricultural materials and the development of biological control technology is low. It is a necessary to develop an effective biocontrol agent to inactivate late blight in the field. AFB2-2 strain is a gram-positive with peritrichous flagella. It can utilize 20 types of carbon sources, like L-arabinose, and D-trehalose at 35℃. The optimal growth temperature of the strain is 37℃. It can survive at 20-50℃ in tryptic soy broth. The maximum salt concentration tolerated by AFB2-2 strain is 7.5% NaCl. AFB2-2 strain inhibited the mycelial growth of seven plant pathogens by an average inhibitory zone of 10.2 mm or more. Among the concentrations of AFB2-2, 10⁷ cfu/ml showed the highest control value of 85.7% in the greenhouse. Among the three concentrations of AFB2-2, the disease incidence and severity of potato late blight at 10⁷ cfu/ml was lowest at 0.07 and 6.7, respectively. The nucleotide sequences of AFB2-2 strain were searched in the NCBI GenBank; Bacillus siamensis strain KCTC 13613, Bacillus velezensis strain CR-502, and Bacillus amyloliquefaciens strain DSM7 were found to have a genetic similarity of 99.7%, 99.7%, and 99.5%, respectively. The AFB2-2 strain was found to harbor the biosynthetic genes for bacillomycin D, iturin, and surfactin. Obtained data recommended that the B. velezensis AFB2-2 strain could be considered as a promising biocontrol agent for P. infestans in the field.

• 한국미생물·생명공학회지
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• 제49권1호
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• pp.111-119
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• 2021

본 연구에서는 국내 자생 식물인 아욱으로부터 새로운 균주를 분리 및 동정하였고 해당 미생물이 생산하는 항미생물질의 활성과 관련 생합성 유전자들을 확인하고자 하였다. 16S rRNA 유전자 서열 정보를 토대로 비교한 결과, 아욱에서 분리된 균주는 Bacillus velezensis이었으며 strain은 MV2라고 명명되었다. 유전체 염기서열 분석을 통해 전체 유전정보를 확인할 수 있었으며, 45.57% GC 함량을 가지는 4,191,702 bp 크기의 1개 컨티그(contig)가 존재하는 것으로 확인되었다. B. velezensis MV2가 정지기에 생산하는 물질 중 항균 활성이 확인된 소수성 물질 분획을 이용하여 항균 활성 스펙트럼 테스트를 진행한 결과, 그람음성균보다 그람양성균에서 더 높은 억제능이 확인되었다. 6종의 곰팡이를 이용한 항진균 활성 테스트에서는 모든 진균에 대해 강한 저해 활성을 보였으며, 특히 F. fujikuroi와 F. graminearum에 대한 항진균 활성이 매우 강하게 나타났다. 세균에 대한 항균물질의 작용 기작 분석을 통해 해당 항균물질은 균을 용해시키는 살균(bactericidal) 특성을 가진 것으로 추측할 수 있었다. B. velezensis MV2의 유전체 염기서열 정보를 통해 이차대사산물 생합성 유전자 cluster를 탐색한 결과 총 47가지 이차대사산물 생산이 예측되었으며, 기존에 밝혀져 있는 물질들과 유사도 80% 이상인 물질은 14개로 확인되었다. 앞서 확인된 내용들을 바탕으로 B. velezensis MV2에서 생성되는 항균물질은 비리보솜 펩타이드성 물질로 예상되며, 향후 항균물질의 동정과 활용 가능성에 대한 추가적인 연구가 필요할 것으로 생각되었다. 기존에 상업적으로 이용되었던 곰팡이에 대한 활성이 낮은 항균물질 생물제제들과 함께 복합기능성 미생물제로 활용하여 식품산업 및 농업에서의 이용 가능성이 있음을 보여주었다.

• Fisheries and Aquatic Sciences
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• 제22권8호
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• pp.17.1-17.9
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• 2019

Bacillus is a diverse genus consisting of more than 200 species with extensive genetic diversity. Their beneficial effects in industrial shrimp farming have been well documented. However, little is known about the biodiversity of the Bacillus spp. in this aquaculture system. Taxonomic analysis by 16S rRNA sequencing does not always allow species-level identification of Bacillus spp. In this study, 26 Bacillus isolates from two industrial Litopenaeus vannamei shrimp ponds in Bac Lieu Province, Vietnam, were analyzed for their genetic diversity by multi-locus sequence typing (MLST). A total of 22 sequence types were identified and segregated into four distinct clusters, corresponding to B. subtilis, B. velezensis, B. siamensis, and B. licheniformis. Bacillus subtilis and B. velezensis accounted for more than 73% of the Bacillus isolates. Notably, the MLST scheme exhibited high discriminatory power and might be further simplified to be a convenient method to identify species of the genus Bacillus.

• 한국균학회지
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• 제40권2호
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• pp.118-123
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• 2012

대표적인 감귤 녹색곰팡이병(Penicillium digitatum) 방제용 생물농약을 개발하고자 제주도내 7개 과수원으로부터 채집된 citrus 잎에서 21균주의 내생세균을 분리하였다. 그 중 5개의 세균이 녹색곰팡이병균 P. digitatum에 항균활성을 나타냈으며, 대치배양에서 가장 강력한 항균활성을 보인 CB3 균주가 선발되었다. CB3 균주는 간상형의 그람 양성세균으로 생리 생화학적 특성과 gyrA 유전자 염기서열 분석에 의해 Bacillus velezensis로 동정되었다. CB3 균주는 감귤 저장병 병원균 Penicillium digitatum에 강력한 항균활성을 나타내었다. $1{\times}10^5$ spores/ml에 이르는 고농도의 P. digitatum을 감귤에 상처접종했을 때에도, $1{\times}10^8$ cfu/ml의 CB3에 의한 방제효과는 66.7%로 매우 높았다. 본 연구결과, Bacillus velezensis CB3의 안정성과 강한 방제활성 등을 고려할 때 유용 친환경적 방제제로서 매우 가치가 있을 것으로 판단된다.