• 한국토양비료학회지
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• 제48권1호
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• pp.36-43
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• 2015

Excess use of chemical fertilizer causes soil acidification and accumulation of salt, and thus might bring to desertification of soil. To overcome this problem, it needs limited usage of chemical fertilizer and increased usage of natural fertilizer as an alternative. In this study, dry soil-borne Bacillus sp. SHL-3, which was isolated from arid and barren soil, with plant growth promoting activity was isolated for identification and to determine optimal culture condition. A bacterial strain SHL-3 had the IAA productivity ($5.16{\pm}0.10mg\;L^{-1}$), ACC deaminase activity ($0.36{\pm}0.09$ at 51 hours) and siderophore synthesis. It was identified as genus Bacillus sp.. Also, optimal culture condition of SHL-3 were $20^{\circ}C$ and pH 7 in LB medium. Bacillus sp. SHL-3 had up to 4% salt tolerance in the medium. We evaluated the plant growth promotion ability of SHL-3 using yam (Dioscorea japonica Thunb.). As a result, Bacillus sp. SHL-3 was effective on the increase of the shoot length (202.4% increase for 91 days). These results indicate that Bacillus sp. SHL-3 can serve as a promising microbial resource for the biofertilizers of soil.

• 농약과학회지
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• 제20권4호
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• pp.369-374
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• 2016

Bacillus velezensis YP2 균주는 쌈채소에서 분리한 Cercospora sp. 1~3, Septoria sp., Colletotrichum sp., Sclerotinia sclerotiorum, Phoma sp., Botrytis cinerea에 대하여 균사생육을 억제하였다. B. velezensis YP2 균주의 LB배양액을 10배 희석액은 적겨자와 청겨자에 발생하는 Erysiphe cruciferarm에 의한 흰가루병을 91.8%와 80.9% 방제효과을 보였다. B. velezensis YP2 균주의 배양액을 10배 희석하여 5일 간격 4회 처리구가 적겨자 흰가루병을 70.6%, 7일 간격 3회 처리구는 65.0%, 10일 간격 2회 처리구는 49.5% 방제하였다. 또한 B. velezensis YP2 균주는 적겨자 종자 발아를 증가시켜고 생육을 촉진하였다. 이상의 결과에서 YP2 균주는 겨자채 흰가루병 방제에 매우 효과적이었다.

• Journal of Microbiology and Biotechnology
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• 제6권2호
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• pp.86-91
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• 1996

Thermostable $\beta$-mannanase from Bacillus sp. YA-14 was purified by acetone precipitation, CM-cellulose, Sephadex G-100 and hydroxyapatite column chromatography from culture supernatant. The final enzyme preparation appeared to be homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). $\beta$-Mannanase appeared to be a monomeric protein with a molecular weight of 67, 000 daltons. The optimal pH and temperature of the enzyme reaction were pH 6.0 and $75^{\circ}C$ , respectively. The enzyme was stable at a pH range of 6.0 to 9.0 and at temperatures between 45 and $85^{\circ}C$. The kinetic constants of $\beta$-mannanase as determined with a galactomannan (locust bean) as substrate were a Vmax of 25 unit/ml and a Km of 1.1 mg/ml. The enzyme had only limited activity on galactomannan substrate. It was suggested that mg $\beta$-mannanase activity is limited by the number of branched $\alpha$-galactose residues.

• 한국수산과학회지
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• 제37권2호
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• pp.91-97
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• 2004

Applications of probiotics to shrimp ponds were carried out to determine their effects on water quality. Fermented solutions consisting of Bacillus spp. and Nitrosomonas spp. were applied to a 4 ha shrimp (Fenneropenaeus chinensis) pond from July to September, 2000. In the pond treated with probiotics, daily variations of DO and pH, and concentrations of DIN and DIP were lower than those in the ponds without probiotic treatment. Concentration of phytoplankton was less variable and the number of species was more variable in the probiotic-treated pond than those in the control pond. Variation of bacterial numbers and the number of Vibrio spp. were lower in the treated pond than those in the control pond. It is confirmed that the probiotics can be used to improve water quality of the shrimp ponds.

• 한국미생물·생명공학회지
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• 제39권2호
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• pp.97-103
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• 2011

GC-1과 GC-4로 명명된 두 종의 그람 양성 박테리아가 제주도 연안해수로부터 동정되었다. 이 두 균주는 16S rRNA 유전자 염기서열 분석과 생리적 특성 분석결과를 토대로 Bacillus 속의 박테리아로 규명되었다. 균주 GC-1의 16S rRNA 유전자 염기서열은 B. tequiliensis와 B. subtilis subsp. inaquosorum의 16S rRNA 유전자 염기서열과 99.91%의 상동성을 보였고, 균주 GC-4의 16S rRNA 유전자 염기서열은 B. altitudinis, B. stratosphericus 및 B. aerophilus의 16S rRNA 유전자 염기서열과 100%의 상동성을 보였다. 그러나 두 균주의 생리학적-유전학적 특성 분석 결과, 이들이 계통적 유연관계를 갖는 다른 Bacillus 속의 균주들과 상당한 차이가 있었고, 따라서 조사된 Bacillus 속과는 다른 속에 속할 가능성이 높았다. 이러한 결과는 Bacillus 속이 진화과정 중에 다양한 변종으로 진화되었음을 암시한다.

• 미생물학회지
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• 제45권2호
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• pp.193-199
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• 2009

오징어 젓갈로부터 호염성 균주를 분리하여 형태적, 생리 생화학적 특성 및 분자계통학적 분석을 통하여 동정하였고, 이 균주가 세포외로 생산하는 호염성 protease를 정제하여 그 특성을 분석하였다. 본 균주는 NaCl 0~14%, $20\sim55^{\circ}C$ 및 pH 5~8에서 성장하였으며, $35{\pm}5^{\circ}C$, pH 7 및 5% NaCl에서 최적으로 성장하였다. 주요 지방산 조성은 anteiso-$C_{15:0}$ (44.70%), anteiso-$C_{17:0}$ (15.76%) 및 $C_{16:0}$ (13.91%)이었고, menaquinone은 MK-7이었으며, DNA G+C 함량은 50.58 mol%였다. 16S rRNA 유전자 염기서열을 통한 계통분석 결과 Bacillus이었으며 Bacillus sp. SJ-10으로 명명하였다. SJ-10 균주 배양액으로부터 40% 황산암모늄 침전과 Mono Q 컬럼크로마토그래피 과정을 거쳐 collagen과 gelatin을 특이적으로 분해하는 약 40 kDa의 세포외 protease를 정제하였다. 이 효소는 $35{\pm}5^{\circ}C$, NaCl $5{\pm}1%$ 및 pH 8에서 최적 활성을 나타냈으며, pH 5~10 범위에서 안정하였다.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1551-1558
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• 2014

The esterase gene Est8 from the thermophilic bacterium Bacillus sp. K91 was cloned and expressed in Escherichia coli. The monomeric enzyme exhibited a theoretical molecular mass of 24.5 kDa and an optimal activity around $50^{\circ}C$ at pH 9.0. A model of Est8 was constructed using a hypothetical YxiM precursor structure (2O14_A) from Bacillus subtilis as template. The structure showed an ${\alpha}/{\beta}$-hydrolase fold and indicated the presence of a typical catalytic triad consisting of Ser-11, Asp-182, and His-185, which were investigated by site-directed replacements coupled with kinetic characterization. Asp-182 and His-185 residues were more critical than the Ser-11 residue in the catalytic activity of Est8. A comparison of the amino acid sequence showed that Est8 could be grouped into the GDSL family and further classified as an SGNH hydrolase. Est8 is a new member of the SGNH hydrolase subfamily and may employ a different catalytic mechanism.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.730-738
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• 2016

est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60℃ and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C₂-C₆). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 춘계학술발표회
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• pp.91-96
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• 2007

선박에서 발생하는 오수를 처리하기 위하여 연속 회분식 공정을 이용하여 유기물의 제거 특성과 미생물 활성제제 투입에 따른 변화, 반응조내에서 우점하고 있는 Bacillus sp. 균주의 상태를 알아보기 위하여 연구를 하였다. 반응조에서 COD의 제거효율은 98.5%, 암모니아성질소는 90%, 총질소의 제거효율은 95%, 인의 제거효율은 93%로 나타났다. SBR를 이용하여 선박폐수를 처리한 결과 안정적인 처리성능을 나타내었다. 미생물 활성제를 첨가하면 바실러스균의 증식율에 좋은 효율을 타나낼 수 있을 것으로 보인다. $NH_4-N$의 제거율은 활성제 주입량이 많을수록 제거율이 향상됨을 알 수 있으나 T-N의 제거율에서는 차이가 없음을 나타내었다. 반응조에서 바실러스균의 평균 우점율은 24.2% 로 나타났고 각 반응단계에서 안정적인 처리효율을 얻을 수 있어 충분히 우점화 되었다고 판단할 수 있었다.

• The Plant Pathology Journal
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• 제31권2호
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• pp.152-164
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• 2015

Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and $YC7010^T$, with antimicrobial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension ($10^7cfu/ml$) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC $15859^T$ (99.67%), Bacillus methylotrophicus KACC $13105^T$ (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC $17177^T$ (99.60%), and Bacillus tequilensis KACC $15944^T$ (99.45%). The DNA-DNA relatedness value between strain $YC7010^T$ and the most closely related strain, B. siamensis KACC $15859^T$ was $50.4{\pm}3.5%$, but it was $91.5{\pm}11.0%$ between two strains YC7007 and $YC7010^T$, indicating the same species. The major fatty acids of two strains were anteiso-$C_{15:0}$ and iso $C_{15:0}$. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC7007 and $YC7010^T$ represent novel species of the genus Bacillus, for which the name Bacillus oryzicola sp. nov. is proposed. The type strain is $YC7010^T$ (= KACC $18228^T$). Taken together, our findings suggest that novel endophytic Bacillus strains can be used for the biological control of rice diseases.