• 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.

• 한국토양비료학회지
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• 제36권6호
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• pp.384-390
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• 2003

논토양의 환경기준 인산지표 예측기술개발을 위하여 논토양 35점을 $25{\pm}1^{\circ}C$ 에서 1, 2, 4주간 담수 항온한 결과 담수 항온 전 풍건 토양의 $0.01M\;CaCl_2$ 가용인산 함량과 유효인산 함량 및 인산흡수능의 관계는 습토로 분석할 경우 상관계수의 크기는 유효인산/인산흡수량>유효인산>유효인산/인산흡수계수>인산흡수량>총인산>인산흡수계수 순이었고, 항온기간별 상관계수 크기는 습토로 분석할 경우 항온이 길어질수록 상관계수는 점점 낮아 졌으나, 건토로 분석할 경우는 이와 반대 경향이었다. 토양의 유효인산 함량과 인산흡수량을 활용하여 $0.01M\;CaCl_2$ 가용인산 농도를 추정할 수 있는 관계식 $0.01M\;CaCl_2-P=0.0828$ (유효인산/인산흡수량) + 0.0374을 얻었으며, 이러한 관계식은 토양의 인산 함량과 인산흡수 특성을 고려하여 작물재배에 필요한 적정 유효인산 함량의 추정과 토양 인산의 유실 가능성 등을 예측하는데 활용될 수 있을 것이다.

• 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.

• 환경영향평가
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• 제16권1호
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• pp.27-33
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• 2007

Hexavalent chromium-contaminated soils are encounted at many unregulated discharge and improper handling of wastes from electroplating, leather tanning, steelmaking, corrosion control, and wood preservation industries. Contamination of hexavalent chromium in the soil is a major concern because of its toxicity and threat to human life and environment. Current technologies for hexavalent chromium-contaminated soil remediation are usually costly and/or cannot permanently prohibit the toxic element from entering into the biosphere. Thus, as an alternative technique, immobilization is seen as a cost-effective and promising remediation technology that may reduce the leachable potential of hexavalent chromium. The purpose of this paper is to develope an immobilization technique for the formation of the geochemically stabilized hexavalent chromium-contaminated soil from the reactions of labile soil hexavalent chromium forms with the added soluble phosphate and chromium reducing agent. From the liquid phase experiment, reaction order of chromium reducing agent, soluble phosphate, alkali solution shows the best removal efficiency of 95%. In addition, actual soil phase experiment demonstrates up to 97.9% removal efficiency with 1:1 molar ratio of chromium reducing agent and soluble phosphate. These results provide evidence for the potential use of soluble phosphate and chromium reducing agent for the hexavalent chromium-contaminated soil remediation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.403-406
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• 2002

This experimental shows the possibility of using as biofertilizer, which convert insoluble inorganic phosphate salts to plant-usable phosphate type by immobilized microorganism with calcium alginate. In the case of culture of P. agglomerans on constant medium pH, phosphate was produced 357 mg/L after 18hrs. And in the case of culture of immobilzed P. agglomerans bead, phosphate was produced maximum 295.6 mg/L after 120 hrs. Also as using rock phosphate as insoluble phosphate salts, phosphate was respectably produced 190.3 and 195.2 mg/L after 36 hrs at free cells and immobilized cells. In our experiments, the using soils contained 23.16 g-P/kg-soil total phosphate and 3.76 g-P/kg-soil soluble phosphate. The result of 1g immobilized bead seeding, soluble phosphate was produced maximum 6.14 g-P/kg-soil phosphate and this value was increased continuously.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.453-457
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• 2006

본 연구는 인산염을 이용하여 오염토양 내 존재하는 납을 불용성 금속인산염으로 고정화시킨 후 자연 상태에서 장기간의 용출특성을 평가하고자 칼럼실험을 수행하였다. 장기용출 실험결과 용출용액 중 납은 거의 검출되지 않았으며 잔류인의 농도도 0.1 mg/L 이하로 나타났다. 이는 납 오염토양에 액상인산염을 주입하여 형성된 hydroxypyromorphite가 장기적으로 안정한 화합물이기 때문으로 사료된다. 장기용출실험 후 칼럼 내 납의 이동특성은 미반응 토양에서는 수직방향으로 이동하는 것으로 나타난 반면에 반응토양에서는 안정한 상태를 유지하고 있었다.

• 한국토양비료학회지
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• 제49권3호
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• pp.265-270
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• 2016

Accumulated Phosphate can be released by ligand exchange reaction of organic acids. The objective of this study was to evaluate effects of the organic acids on the availability of phosphate and the growth of crop in phosphate and salts accumulated soil. Soil samples were collected from farmer's plastic film house. Available phosphate and electrical conductivity of soil were $3,005mg\;kg^{-1}$ and $16.63mg\;kg^{-1}$ which were 6 and 8 times higher than the optimum range of soil for crop growth, respectively. Corns were cultivated in pots for 2 months. Treatments were no treatment (control), phosphate fertilizer (P), citric acid (CA) 1, 5, 10 mM, and oxalic acid (OA) 1, 5, 10 mM. Water soluble phosphorus, available phosphate, corn growth and uptake were determined after cultivation. Results showed that organic acids increased water soluble phosphorus and available phosphate. For the level of 10 mM, the order of effectiveness of organic acids for water soluble P was citric acid (44%) > oxalic acid (32%). Height and dry weight of corns were increased significantly by the treatment of citric acid 1 and 5 mM. Also, corn absorbed more phosphorus, nitrogen, potassium, calcium and magnesium in the treatment of citric acid 1 mM than these of other treatments. Even though phosphate availability of soil was enhanced by addition of citric acid 10 mM, the growth of corns decreased because high concentration of citric acid caused salt damage by increasement of electrical conductivity. Thus, the citric acid of 1 mM has the potential to improve the availability of phosphate and the healthy growth of corns.

• 한국토양비료학회지
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• 제45권2호
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• pp.169-176
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• 2012

Among the major nutrients, phosphorus is by far the least mobile and available to plants in most soil conditions. A large portion of soluble inorganic phosphate applied to soil in the form of phosphate fertilizers is immobilized rapidly and becomes unavailable to plants. To improve the plant growth and yield and to minimize P loss from soils, the ability of a few soil microorganisms converting insoluble forms into soluble forms for phosphorus is an important trait in several plant growth-promoting microorganisms belonging to the genera Bacillus and Pseudomonas and the fungi belonging to the genera Penicillium and Aspergillus in managing soil phosphorus. The principal mechanism of solubilization of mineral phosphate by phosphate solubilizing bacteria (PSB) is the release of low molecular weight organic acids such as formic, acetic, propionic, lactic, glycolic, fumaric, and succinic acids and acidic phosphatases like phytase synthesized by soil microorganisms in soil. Hydroxyl and carboxyl groups from the organic acids can chelate the cations bound to phosphate, thereby converting it into soluble forms.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.335-339
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• 2002

Laboratory experiments were conducted using pure cultures of Acinetobacter under an-aerobic/aerobic cyclic conditions to explain the release and uptake of soluble phosphate in an activated sludge process showing enhanced biological phosphate removal (EBPR). Under anaerobic/aerobic cyclic conditions in a Sequencing Batch Reactor (SBR), COD uptake concurrent with soluble phosphate release by Acinetobacter was not significant during the anaerobic periods, indicating that EBPR would not be established in pure cultures. However Acinetobacter cells accumulated higher phosphate content (5.2%) in SBR than that obtained (4.3%) from batch experiments. These results suggest that Acinetobacter sp. may not follow the proposed pattern of behavior of poly-P bacteria in EBPR activated sludge Plants.

• 한국토양비료학회지
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• 제1권1호
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• pp.27-41
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• 1968

우리나라 수도작(水稻作)에 대(對)한 수종(數種) 인산질비료(燐酸質肥料)의 비효를 명확(明確)히 하기 위(爲)하여 기왕(旣往)에 실시(實施)한 재배시험(栽培試驗) 결과(結果)를 검토(檢討)하고 또 비효의 차이(差異)를 가져온 원인(原因)을 캐 볼 목적(目的)으로 1963~1964년(年)에 수경(水耕) 및 토경재배(土耕栽培)[폿트(깡통을 썼음)시험(試驗)]를 실시(實施)한바 그 결과(結果)는 다음과 같다. 1. 수경재배(水耕栽培)를 통(通)한 순수한 인산질비료(鱗酸質肥料)로서의 비효는 수용성인산(水溶性燐酸)이 가장 크고 구용성(拘溶性) 인산(燐酸)인 용린(熔燐)이나 인산제(燐酸第)2석회(石灰)가 그 뒤를 따랐으나 토경재배(土耕栽培) (폿트시험(試驗))나 실제 포장시험(圃場試驗)에서는 용린(熔燐)의 효과가 수용성(水溶性)인 중과석(重過石)의 효과보다 우수(優秀)한 경우(境遇)가 많았고 하이포인비(燐肥)나 용성인비(熔成燐肥), 화성인비(化成燐肥), 스래그인비(燐肥)는 중과석(重過石)과 비슷하거나 이보다 다소(多少) 떨어지는 비효를 보이는 경우(境遇)가 많았으며 린회석분말(燐灰石粉末)의 비효는 대체(大體)로 타비료(他肥料)보다 월등히 떨어진다. 2. 용린(熔燐)의 비효가 중과석(重過石)보다 대체(大體)로 컸든 이유(理由)로는 용린(熔燐)이 가. 토양산성(土壤酸性)을 중화(中和)하는 능력(能力)이 있고 나. 마그네슘을 공급(供給)하며 동(同) 공급(供給)이 치환성토양염기(置換性土壤鹽基)를 균형(均衡)된 조건(條件)으로 유인하고 다. 마그네슘이 인산(燐酸)의 이전(移轉)(식물체내(植物體內)에서)이나 인산(燐酸)의 흡수(吸收)를 조절(調節)하기 때문으로 추리(推理)되었다.