• KSBB Journal
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• v.13 no.5
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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.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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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.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.36-41
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• 2007

Phosphate-solubilizing microorganisms were isolated from soil around Kyungnam and Kyungbook regions using potato dextrose agar-calcium phosphate medium. A fungus with the greatest phosphate-solubilizing activity was selected and identified to Aspergillus sp. PS-104, based on the morphological characteristics of conidiophore and conidia; unbranching type of conidiophore, terminally swelling of conidiophore and septate of mycelium, in malt extract agar and potato dextrose agar media. The optimum temperature and initial pH to solubilize rock phosphate in potato dextrose broth-rock phosphate medium were $30^{\circ}C$ and pH 7.0, respectively. In these optimum conditions, phosphate-solubilizing activities of Aspergillus sp. PS-104 against four twos of insoluble phosphate, tricalcium phosphate, aluminium phosphate, hydroxyapatite and rock phosphate, were quantitatively determined. As result, the maximum phosphate-solubilizing activity was obtained with tricalcium-phosphate (1,900 ppm) while minimum activity was obtained with hydroxyapatite (320 ppm). Futhermore, phosphate-solubilizing activity of Aspergillus sp. PS-104 was found higher when treated with nitrates as compared to the ammonium salts as a nitrogen sources.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.77-81
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• 2007

In order to minimize the mycelial pellet size of a high phosphate-solubilizing fungus, Aspergillus sp. PS-104 in liquid media, one of the critical obstacles during the submerged culture of filamentous fungi, an investigation was focused on the culture conditions (media and inoculum size) and additives (different soils, surfactants and polyethylene glycol 200). When the fungus was cultured in PDB, SDB and YPD media. their pellet sizes decreased in the order of SDB=YPD>PDB. At the higher concentrations of initial inoculum ranging from $1{\times}10^3$ to $1{\times}10^7$ conidia/ml, the smaller size of pellet was formed in the PDB medium. In addition, the pellet size was effectively reduced by 1/6${\sim}$1/4 by the addition of 0.1% soil containing zeolite, diatomite, loess, kaoline and talc, excluding bentonite. The addition of 0.1% Tween 80, Triton X-100 and PEG 200 also decreased the pellet size, but SDS completely inhibited the fungal growth.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.1-7
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• 2001

We investigated the capability of the phosphate-solubilizing fungus, Penicillium sp. GL-101, to solubilize in vitro some insoluble rock phosphate via possible mechanisms: acidification of the medium, production of chelating metabolites, redox activity, and so on. GL-101 was able to solubilize rock phosphate (mostly calcium phosphate) in a liquid potato dextrose broth(PDB) medium, as determined by spectrophotometric analyses. Acidification was the major mechanism of solubilization since the pH of cultures fell below 4.0 and in cultures containing 1.0%(w/v) loess the pH dropped from 7.0 to 3.2. More than 10 mg/mL concentrations of citric acids were detected by high-performance liquid chromatography(HPLC) in the culture supernatants. Also this fungus showed the phosphatase activity (over 1.3 unit) to contribute partially releasing phosphate from rock phosphate, when supplemented with 1.0% loess in culture broth. The chelating activity of GL-101 in culture supernatants was not present because 2-ketogluconic acid, a chelating agent for the phosphate, was produced only a basal level. Therefore, the solubilization mechanism of rock phosphate by Penicillium sp. GL-101 involves both acidification due to citric acid production and phosphatase activity.

• Applied Biological Chemistry
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• v.40 no.4
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• pp.329-333
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• 1997

Phosphate solubilizing microorganisms (1,000 bacteria and 200 fungi) were isolated from soil around Kyungnam and Kyungbook regions using potato dextrose agar-calcium phosphate medium. A fungus with the greatest phosphate solubilizing activity was selected and identified to Penicillium sp. GL-101, 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 and initial pH to solubilize rock phosphate in potato dextrose broth-rock phosphate medium were $25^{\circ}C$ and pH 7.5, respectively. In these optimum conditions, phosphate solubilizing activities of Penicillium sp. GL-101 against four types of insoluble phosphate: tricalcium-phosphate, aluminium phosphate, hydroxyapatite and rock phosphate, were quantitatively determined. As results, this fungus highly discharged free phosphates to the culture broth with the concentrations of 1,152 ppm against tricalcium-phosphate, 565 ppm against rock phosphate, 292 ppm against aluminium phosphate, and 217 ppm against hydroxyapatite, respectively.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.17-23
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• 2002

In order to investigate effects if loess on the mycellial pellet formation a phosphate-solubilizing fungus. Aspergillus sp. PS-104 was cultured in potato dextrose broth containing loess. The strain formed an amorphous pellet or loose aggregates agitated at a low speed (50 rpm) while spherical and regular pellets at a high speed (150 rpm) The higher concentration of loess was added, the smaller size of a pellet was formed during the submerged culture of the strain. As shown in results, being cultured in the PDB medium supplemented with 1.0% loess the pellet size was maximally reduced to a fourth compared to the control. Evaluating the addition effect of several components of loess such as $SiO_2$, $Fe_2O_3$, $Al_2O_3$, $CaCO_3$, $CaSO_4$ and $MgCO_3$ on the reduction of mycellial pellet size the higher concentration was supplied, the smaller size of pellet was formed except $Al_2O_3$. And the smallest pellet size was recorded at the concentration of 1.0% (W/V) magnesium carbonate.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1273-1279
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• 2005

Penicillium oxalicum strain CBPS-3F-Tsa, an efficient phosphate solubilizing fungus, was evaluated for its production of organic acid in vitro and effect of inoculation on the growth promotion of Maize under greenhouse conditions. The fungus solubilized 129.1, 118.8, and 54.1 mg P/1 of tricalcium phosphate [$Ca_{3}(PO_{4})_{2}$], aluminum phosphate ($A1PO_{4}$),and ferric phosphate ($FePO_{4}$), respectively, after 72 h of incubation. Malic acid, gluconic acid, and oxalic acid were detected in the flasks supplemented with various phosphate sources [240, 146, 145 mM/1 $A1PO_{4},\;FePO_{4},\;and\;Ca_{3}(PO_{4})_{2}$, respectively] together with a large amount of malic acid followed by the other two. The effects of inoculation of P. oxalicum CBPS-3F-Tsa on maize plants were studied under pot culture conditions. P. oxalicum CBPS-3F-Tsa was inoculated to maize plants alone or together with inorganic phosphates in the form of fused phosphates (FP) and rock phosphates (RP). Inoculation of P. oxalicum CBPS-3F-Tsa increased the plant growth and N and P accumulation in plants, compared with control plants, and also had positive effects when applied with RP. The results of this study show that the fungus P. oxalicum strain CBPS-3F-Tsa could solubilize different insoluble phosphates by producing organic acids, particularly malic acid, and also improved the efficiency of RP applied to maize plants.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.439-440
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• 2000

This study was conducted to preserve viability of Aspergillus sp. PS-104, a phosphate-solubilizing fungus, for more than 6 months. The number of Aspergillus sp. PS-104 conidia stored at $25^{\circ}C$ with various concentrations of additives was counted on potato dextrose agar at the intervals of 2 weeks. When PEG 200 was added with concentration of 0.1%, viability of the conidia was increased more than 10 times to compare with control.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.398-399
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• 2001

A fungus. Penicillium sp. PS-113. with high phosphate-solubilizing activities was isolated from soil and tested the viability in POA medium supplemented with various concentrations of Trio in order to develop a dispersing agent for liquid formulation. Moreover, the number of Penicillium sp. PS-113 conidia, stored at $4^{\circ}C$ and $25^{\circ}C$ with Trio(0.1%) and various concentrations of additives($Cu^{++}$ $Mo^{++}$, bio-ceramic, Tween 80, PEG 200. diatomite. SDS), was counted on PDA at the intervals of 2 weeks. As a result, the liquid formulation containing 0.1 %( v/v) Trio was remarkably improved in dispersing ability and the viability of the conidia, and each of the supplements (0,01% $Mo^{++}$, 0.5% bio-ceramic. 1.0% Tween 80, 1.0% PEG 200) was similar to the 0.1% Trio.