• 한국토양비료학회지
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• 제41권5호
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• pp.348-353
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• 2008

토양에서 인산가용화 미생물의 역할을 탐색하기 위해, 밭과 시설재배 토양에 서식하는 인산가용화 미생물의 특성을 조사하였다. 노지 밭 토양에 비해 시설재배지 토양에서 EC가 높았으며, 토양 pH, 유기물, 유효인산, 치환성 양이온 및 총 인도 시설재배지에서 비교적 높은 경향이었다. 인산가용화 세균의 수는 시설재배지 토양이 밭 토양보다 높았으나, 인산가용화 세균의 종류는 밭 토양에 많았다. 인산가용화 세균의 밀도와 인산가용화능 간에 정의 상관이 있었다. 밭 토양에서는 Bacillus, Cedecea, Brevibacillus, Paenibacillus Pseudomonas, Serratia속 등이 시설재배지 토양에서는 Bacillus, Cellulomonas 속 등의 인산가용화 세균이 분리되었다.

• KSBB Journal
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• 제13권5호
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• pp.497-501
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• 1998

A fungus with high phosphate solubilizing activites was isolated from soil using potato dextrose agar-calcium phosphate medium and identified to Penicillium sp. PS-113, based on the morphological characteristics of conidiophore and conidia; flask shape of phialide, simple branching type of conidiophore, and columnar shape of conidial head, in malt extract agar and potato dextrose agar media. The optimum temperature ad initial pH to solubilize rock phosphate in potato dextrose broth-rock phosphate medium were 30$^{\circ}C$ and pH 8.0, respectively. In these conditions phosphate solubilizing activities of Penicillium sp. PS-113 against four types of insoluble phosphate like tricalcium-phosphate, aluminium phosphate, hydroxyapatite and rock phosphate were quantitatively determined. As results, this fungus highly produced free phosphates to the culture broth with the concentrations of 1,283 ppm against tricalcium-phosphate, 585 ppm against rock phosphate, 528 ppm against aluminium phosphate, and 242 ppm against hydroxyapatite, respectively.

• 한국환경농학회지
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• 제26권1호
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• pp.36-41
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• 2007

PDA-calcium phosphate 평판배지를 이용하여 경상남북도 일대의 토양으로부터 인산가용화능이 우수한 사상균을 분리하고 배양특성을 조사하였다. 최종적으로 분리한 인산가용화능이 우수한 사상균 PS-104 균주를 선발하여 형태적 특성을 조사한 결과 이 균주의 분생자는 비가지형으로 끝이 돌출되어 있으며, 균사가 격막으로 형성되는 등의 특징을 갖는 Aspergillus sp. PS-104 균주로 동정되었다. 이 균주의 인광석 분해능이 최대가 되는 최적 배양온도와 pH는 각각 $30^{\circ}C$와 pH 7.0이었다. 이와 같은 배양조건에서 tricalcium phosphate, aluminium phosphate, hydroxyapatite, 인광석 등의 난용성 인산염에 대한 이 균주의 인산가용화능을 살펴보면 최대 인산가용화능은 tricalcium-phosphate 처리구(1,900 ppm)에서, 최소 인산가용화능은 hydroxyapatite 처리구(320 ppm)에서 확인되었다. 또한 이 균주의 인산가용화능은 질소원으로 첨가한 ammonium 염보다 nitrate 염에서 높게 나타났다.

• 생명과학회지
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• 제23권2호
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• pp.242-248
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• 2013

본 연구의 목적은 우수한 미생물 제제 개발용 인산염 가용화 균주의 개발이다. 경작지 토양에서 분리한 인산염 가용화 균주의 특성 및 16S rDNA 염기서열을 조사한 결과 Bacillus subtilis HR-1019로 동정되었다. Bacillus subtilis HR-1019는 hydroxyapatite, tri-calcium phosphate 및 aluminum phosphate 3가지의 난용성 인산염을 모두 가용화하였다. 난용성 인산염의 분해능이 최대가 되는 배양온도는 $37^{\circ}C$이었으며, 배양초기 pH가 5.0이었다. 탄소원으로 glucose를 5% 첨가시 가용화능이 높았으며, 가용화된 유리인산의 함량이 증가함에 따라 pH가 크게 감소하였다. 분리균주 HR-1019가 식물병원균에 대하여 균의 생육을 저지하는 clear zone 확인으로 항균효과를 확인하였다.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.1-7
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• 1999

A fungus, Penicillium sp. PS-113, isolated from soil showed the high phosphate-solubilizing activity in patato dextrose broth-rock phosphate to produce free phosphates to the culture broth with the concentrations of 585 ppm against rock phosphate. In this medium, the optimum temperature and initial pH to solubilize rock phosphate were 30$^{\circ}C$ and pH 7.5, respectively. In order to make the mass production of the conidia from this fungus, we cultured in on various solid-based media like barley, corn, wheat, rice, rice bran, and compost. As a result, the fungus highly produced conidia ranging from 2.1 to $5.1{\times}10_9$ conidia/g${\cdot}$media on these solid media except compost-based medium, which was 0 times less than others. Effects of inoculation of the phosphate solubilizing fungus as a biofertilizer were studied in perlite-based pot cropped with Zea mays Suwon 19. Inoculation of Penicillium sp. PS-113 increased in plant height (1.4 times), plant weight (5.2~8.1 times) and root length (1.1~1.2 times) at 60-day cultivation, compared to Hogland solution either without $NH_4H_2PO_4$ or displace $NH_4H_2PO_4$ to powdered rock phosphate, a phosphorus source for plant growth.

• Journal of Life Science
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• 제10권1호
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• pp.64-65
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• 2000

Insoluble phosphate-solubilizing bacteria are routinely screened by a plate assay method using Pikovskaya agar and a modified Pikovskaya medium. A modified Pikovskaya medium to improve the clarity of the yellow-colored halo has not necessarity improved the plate assay. Colonies of phosphate-solubilizing bacteria tested could be redily selected after 48 h of incubation by green-colored colony formation on plate in which bromcresol green(BCG) was included. Among them, two bacterial strains did not produce distinct yellow halos after 48 h of incubation. We suggest that the green colony formation on plate medium containing BCG is advantageous ofr rapid isolating phosphate-solubilizing bacteria directly from soil.

• Journal of Microbiology and Biotechnology
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• 제27권4호
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• pp.844-855
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• 2017

Phosphate-solubilizing bacteria (PSB) have the ability to dissolve insoluble phosphate and enhance soil fertility. However, the growth and mineral phosphate solubilization of PSB could be affected by exogenous soluble phosphate and the mechanism has not been fully understood. In the present study, the growth and mineral phosphate-solubilizing characteristics of PSB strain Burkholderia multivorans WS-FJ9 were investigated at six levels of exogenous soluble phosphate (0, 0.5, 1, 5, 10, and 20 mM). The WS-FJ9 strain showed better growth at high levels of soluble phosphate. The phosphate-solubilizing activity of WS-FJ9 was reduced as the soluble phosphate concentration increased, as well as the production of pyruvic acid. Transcriptome profiling of WS-FJ9 at three levels of exogenous soluble phosphate (0, 5, and 20 mM) identified 446 differentially expressed genes, among which 44 genes were continuously up-regulated when soluble phosphate concentration was increased and 81 genes were continuously down-regulated. Some genes related to cell growth were continuously up-regulated, which would account for the better growth of WS-FJ9 at high levels of soluble phosphate. Genes involved in glucose metabolism, including glycerate kinase, 2-oxoglutarate dehydrogenase, and sugar ABC-type transporter, were continuously down-regulated, which indicates that metabolic channeling of glucose towards the phosphorylative pathway was negatively regulated by soluble phosphate. These findings represent an important first step in understanding the molecular mechanisms of soluble phosphate effects on the growth and mineral phosphate solubilization of PSB.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.94.2-95
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• 2003

E. intermedium 60-2G possessing a strong ability to solubilize insoluble phosphate, has plant growth-promoting activity, induced systemic resistance activity against scab pathogen in cucumber, and antifungal activity against various phytopathogenic fungi. The phosphate solubilizing activity of 60-2G may be mainly accomplished by production of gluconic acid through a direct extracellular oxidation of glucose by glucose dehydrogenase that required a PQQ cofactor for its activation. A pqq gene cluster conferred Phosphate-solubilizing activity in E. coli DH5${\alpha}$ was cloned and sequenced. The 6,783 bP pqq sequence had six open reading frames (from A to F) and showed 50-95％ homology to pqq genes from other bacteria. The E. coli strain expressing the pqq genes solubilized phosphate from hydroxyapatite after a pH drop to 4.0, which paralleled in time the secretion of gluconic acid. To study the role of PQQ in biocontrol traits of E. intermedium, PQQ mutants of 60-2G were constructed by marker exchangee mutagenesis. The PQQ mutants of E. intermedium were lost activities of solubilizing phosphate, growth inhibition of phytopathogenic fungi, and plant growth promotion. These findings suggest that PQQ plays an important role, possibly activation of certain enzymes, in several beneficial bacterial traits of E. intermedium by as yet an unknown mechanism.

• 한국토양비료학회지
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• 제41권5호
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• pp.342-347
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• 2008

미생물에 의해 분비되는 유기산에 의해 난용성 인산염이 가용화되어 토양 용액 중으로 확산되면 식물 혹은 다른 미생물이 이용할 수 있게 된다. 본 연구는 논 토양을 대상으로 볏짚 퇴비, 석회, 규산 등의 개량제가 토양 인산 가용화균의 생태에 미치는 영향을 조사하였다. 인산가용화 균의 비율이 증가할 수록 토양의 유효인산 함량이 높아지는 경향을 보였다. 논 토양 호기성 세균에 대한 인산가용화 세균의 비율은 석회, 규산 및 퇴비를 함께 시용한 처리구에서 크게 증가하였다. 논 토양에서 분리된 인산가용화 세균은 Aquaspirillum, Arthrobacter, Bacillus, Flavobacterium, Micrococcus, Micromonospora, Pseudomonas속 등이었으나 가장 많이 분리된 균은 Bacillus속이 그 다음으로는 Pseudomonas속이 우점하였다.

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.773-777
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• 2008

Phosphate solubilizing bacteria (PSB) were isolated from the rhizosphere of Chinese cabbage and screened on the basis of their solubilization of inorganic tricalcium phosphate in liquid cultures. Ten strains that had higher solubilization potential were selected, and they also produced indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and siderophores. The strains were identified to be members of Pseudomonas, by 16S rDNA sequence analysis. Seed bacterization with PSB strains increased the root elongation and biomass of Chinese cabbage in seedling culture, although they had no effect on phosphorus uptake of plants. The plant growth promotion by PSB in this study could be due to the production of phytohormones or mechanisms other than phosphate solubilization, since they had no effect on P nutrition.