• Biotechnology and Bioprocess Engineering:BBE
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• 제7권4호
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• pp.201-205
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• 2002

The growth conditions of Pantoea aggicmerans, a phosphate solubilizing organism, were studied In our laboratory to determine the optimal conditions. Pantoea aggionerans showed the highest growth rate at 30$\^{C}$, pH 7.0 and 2 vvm, after 50 h cultivation. A certain relationship between pH and phosphate concentration was evident when the glucose concentration in the me dium was changed. Increasing glucose concentration increased the pH buffer action of the broth. At glucose concentrations higher than the optimum concentration of 0.2 M, the cell growth was retarded. P. agglomerans consumed glucose as a substrate to produce organic acids which caused the pH decrease in the culture medium. The phosphate concentration in the medium was increased by the presence of the organic acids, which solubilized insoluble phosphates such as hydroxyapa-tite.

• 한국토양비료학회지
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• 제42권1호
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• pp.29-36
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• 2009

14종의 인산용해미생물을 근권으로부터 분하였고, 16S rRNA gene 염기서열에 의하여 동정하였다 그 중 hydroxyapatite를 첨가한 배지에서 인산용해능력이 가장 뛰어난 Acinetobacter sp., Pseudomonas orientalis, Enterobacter asburiae 3종을 선택하였다. 선택된 3종의 미생물에 의해 용해된 인산의 농도는 $200\;mg\;L^{-1}$에서부터 $2300\;mg\;L^{-1}$까지 이르렀으며, 증가된 인산 농도는 배양액의 pH와 역으로 비례하였다. HPLC를 사용하여 유기산을 측정한 결과 Acinetobacter sp.는 gluconic acid를, P. orientalis는 gluconic acid와 2-ketogluconic acid를 그리고 E. asburiae는 acetic acid와 succinic acid를 분비하였다. 한편 P. orientalis와 E. asburiae는 각각 $372\;mg\;L^{-1}$와 $191\;mg\;L^{-1}$의 IAA 분비하였고, Acinetobacter sp.는 IAA를 생성하지 못했다. 인산용해미생물이 오이의 생장에 미치는 효과를 조사한 결과, P. orientalis를 처리한 시험구가 가장 높았고, E. asburiae, Acinetobacter sp., control 순으로 나타났다. 이러한 식물생장 효과는 인산용해미생물에 의한 불용성 인산용해와 IAA 생산과 관련이 있다고 생각된다.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1435-1446
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• 2022

Zinc-solubilizing bacteria can convert the insoluble form of zinc into soluble forms available to plants. This study was conducted to isolate and screen zinc-solubilizing actinobacteria from rhizosphere soils and to assess their effect on vegetable soybean growth. In total, 200 actinobacteria strains belonging to 10 genera were isolated from rhizosphere soil samples. Among these isolates, four showed zinc solubilization with solubilizing index values ranging from 3.11 to 3.78 on Bunt and Rovira agar supplemented with 0.1% zinc oxide. For the quantitative assay, in broth culture, strains CME34 and EX51 solubilized maximum available zinc contents of 529.71 and 243.58 ㎍/ml. Furthermore, indole-3-acetic acid (IAA) and ammonia were produced by these two strains, the strain CME34 produced the highest amount of IAA 4.62 ㎍/ml and the strain EX51 produced the highest amount of ammonia 361.04 ㎍/ml. In addition, the phosphate-solubilizing abilities in Pikovskaya's medium of CME34 and EX51 were 64.67 and 115.67 ㎍/ml. Based on morphological and biochemical characterization and 16S rDNA sequencing, the strains CME34 and EX51 were closely related to the genus Streptomyces. In a greenhouse experiment, single-strain inoculation of Streptomyces sp. CME34 or EX51 significantly increased the shoot length, root length, plant dry weight, number of pods per plant and number of seeds per plant of vegetable soybean plants compared to the uninoculated control. These findings facilitated the conclusion that the two Streptomyces strains have potential as zinc solubilizers and can be suggested as bioinoculants to promote the growth and yield of soybean.

• 방사선산업학회지
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• 제3권1호
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• pp.39-45
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• 2009

Three mineral phosphate solubilizing (MPS) bacteria where isolated from rhizosphere soil samples of common bean and weed plants. 16S rDNA analysis indicated that the isolate P2 and P3 are closely related to Pantoea dispersa while isolate P4 is closely related to Pantoea terrae. Isolates P2 and P3 recorded $381.60{\mu}g\;ml^{-1}$ and $356.27{\mu}g\;ml^{-1}$ of tricalcium phosphate (TCP) solubilization respectively on 3 days incubation. Isolate P4 recorded the TCP solubilization of $215.85{\mu}g\;ml^{-1}$ and the pH was dropped to 4.44 on 24 h incubation. Further incubation of P4 sharply decreased the available phosphorous to $28.94{\mu}g\;ml^{-1}$ and pH level was raised to 6.32. Gamma radiation induced mutagenesis was carried out at $LD_{99}$ dose of the wild type strains. The total of 14 mutant clones with enhanced MPS activity and 4 clones with decreased activity were selected based on solubilization index (SI) and phosphate solubilization assay. Mutant P2-M1 recorded the highest P-solubilizing potential among any other wild or mutant clones by releasing $504.21{\mu}g\;ml^{-1}$ of phosphorous i.e. 35% higher than its wild type by the end of day 5. A comparative evaluation of TCP solubilization by wild type isolates of Pantoea and their mutants, led to select three MPS mutant clones such as P2-M1, P3-M2 and P3-M4 with a potential to release >$471.67{\mu}g\;ml^{-1}$ of phosphorous from TCP. These over expressing mutant clones are considered as suitable candidates for biofertilization.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2001년도 제31회 학술심포지움 및 춘계학술대회
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• pp.72-72
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• 2001

• 한국토양비료학회지
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• 제40권6호
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• pp.442-446
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• 2007

토양에 고정되어 축적된 난용성 인산염을 가용화하는 유용세균을 선발하여 생물비료로 이용하고자 고추, 토마토, 상추, 오이, 목초, 잔디의 근권토양 및 뿌리표면에서 인산가용화능이 있는 세균을 분리하였다. 선발된 인산가용화균은 16S rRNA 염기서열과 생화학적특성 등에 의해 동정되었으며, 난용성인산 가용화기능이 우수한 세균 Pseudomonas sp. CL-1 및 Kluyvera sp. CL-2균주를 선발하였다. Pseudomonas sp. CL-1균주는 esculin과 gelatin, casein을 가수분해하였고, 그리고 glucose, arabinose, mannose, mannitol, N-acetyl-glucosamine, gluconate, caprate, adipate, malate, citrate 등을 이용하였다. Kluyvera sp. CL-2 균주는 esculin과 CM-cellulose를 가수분해 하였고 acetoin을 생성하였다. 그리고 glucose, arabinose, mannose, mannitol, N-acetyl-glucosamine, maltose, gluconate, malate, citrate 등을 이용하였다. Pikovskaya's medium에서 선발균주의 난용성인산 $Ca_3(PO_4)_2$의 인 가용화량을 정량한 결과 Pseudomonas sp. CL-1과 Kluyvera sp. CL-2 균주는 접종후 1일, 3일에 각각 148.0, $193.4(P\;mg\;L^{-1})$와 482.8 mg, 493.6 mg의 인 가용화량을 나타내었다

• 한국토양비료학회지
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• 제45권5호
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• pp.817-821
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• 2012

Soil samples collected from abounded mines of Boryeong area in South Korea were used in isolating bacterial strains and their capacity to solubilize inorganic phosphates and heavy metal tolerance were assessed in vitro. Three different inorganic phosphate sources (Ca phosphate, Fe phosphate, and Al phosphate) and four different heavy metals (Co, Cd, Pb and Zn) each with three concentrations ($100{\mu}g\;mL^{-1}$, $200{\mu}g\;mL^{-1}$, and $400{\mu}g\;mL^{-1}$) were used. The bacterial isolates PSB-1, PSB-2, PSB-3, and PSB-4 solubilized significantly higher amount of Ca phosphate during the first five days of incubation though subsequent drop in soluble phosphorus level in the medium was observed at the later stage (after 5 days) of the incubation. Solubilization of Ca phosphate and Fe phosphate was concomitant with the acidification of the culture medium compared to the control where it remained constant. Isolated strains could solubilize Fe phosphate to certain extent ($25-45{\mu}g\;mL^{-1}$) though solubilization of Al phosphate was found negligible. All the isolates were tolerant to heavy metals (Cd, Pb, and Zn) up to the concentration of $400{\mu}g\;mL^{-1}$ except PSB-1 and PSB-8, which were shown to be vulnerable to Co even at $100{\mu}g\;mL^{-1}$. Heavy metal tolerant strains should be further evaluated for plant growth promoting activities also under field conditions in order to assess their agricultural and environmental significance.

• 생명과학회지
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• 제18권6호
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• pp.878-883
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• 2008

생물비료의 개발을 위하여 분리된 난용성 인산염의 가용화능이 우수한 균주인 Aeromonas hydrophila DA33의 분자육종을 위해 인산가용화 관련 유전자를 도입하였다. E. coli의 gdh 유전자를 도입한 A. hydrophila DA33은 GDH 활성이 증가하여 유전자가 발현됨을 확인하였으며, wild type에 비해 GDH 활성이 약 40% 정도 높게 나타났으며, 이는 도입된 gdh 유전자의 발현에 의한 것으로 보여 진다. 이 균주는 인산가용화에 기여하는 유기산인 gluconate의 생성도 증가하였다. A. hydrophila DA33의 wild type과 gdh 유전자를 도입한 A. hydrophila pGHS/DA33의 난용성 인산염 가용화능을 실험한 결과, gdh 유전자를 도입한 균주의 인산 가용화능이 약 1.4배 정도의 효과를 보였다. 지금까지의 결과로 비춰볼때 앞으로 생물 비료로서의 A. hydrophila DA33 이용 가능성을 나타내며, 분자육종균 A. hydrophila pGHS/DA33은 생물비료로서의 효율성을 가질 것으로 기대된다.

• 한국환경과학회지
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• 제17권9호
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• pp.1033-1037
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• 2008

The effects of inorganic salts, inoculum concentration, aeration rate and shaking speed on insoluble phosphate solubilization by Pseudomonas fluorescens RAF15 were investigated. Soluble phosphate production was dependent on the presence of $MgCl_2{\cdot}6H_2O$ and $MgSO_4{\cdot}7H_2O$ in the medium. Supplementation of medium with 0.01% $CaCl_2{\cdot}2H_2O$ and 0.01% NaCl slightly increased soluble phosphate production. The optimal medium compositions for the solubilization of insoluble phosphate by P. fluorescens RAF15 were 1.5% glucose, 0.005% urea, 0.3% $MgCl_2{\cdot}6H_2O$, 0.01% $MgSO_4{\cdot}7H_2O$, 0.01% $CaCl_2{\cdot}2H_2O$ and 0.01% NaCl, respectively. Optimal inoculum concentration was 2.0%(v/v). Maximum soluble phosphate production was obtained with 20-50 ml/250-ml flask and 200 rpm of shaking speed, respectively. The addition of EDTA decreased cell growth and soluble phosphate production.