• Journal of Korea Foundry Society
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• v.44 no.3
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• pp.86-93
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• 2024

• 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.

• The Korean Journal of Pesticide Science
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• v.13 no.1
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• pp.21-27
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• 2009

A study was carried out to find out the methodology of biological treatment for wastes and wastewater caused by an organophosporus insecticide, fenitrothion, using fenitrothion-degrading microorganism. A fenitrothion-degrading microorganism was isolated by using a selective nutrient broth (NB) medium including fenitrothion, and identified to Bacillus sphaericus NFol based on its morphological and biochemical characteristics. Further, investigation was processed to determine the optimal culture conditions degrading fenitrothion in NB medium by using the NFo1 strain. As results, the cultural conditions determined for temperature, initial pH and inoculum for the optimum growth of the strain and degradation of fenitrothion, which has a exact co-relationship between both of them, were $35^{\circ}C$, 7.5 and 1.5 at $OD_{660}$ value, respectively. In this conditions, fenitrothion could be degraded within 5 days over 90% at the high concentrations of fenitrothion, upto 200 mg/L.

• KSBB Journal
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• v.14 no.3
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• pp.337-341
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• 1999

In order to investigate effects of loess on the mycelial pellet formation a phosphate dissolving fungus, Penicillium sp. GL-101, was cultured in potato dextrose broth containing loess. The strain formed an amorphous pellet or loose aggregates agitated at a low speed(50rpm) while spherical and regular pellets at a high speed(150rpm). The higher concentration of loess, the smaller size of a pellet in the medium formed by the strain. Cultured in the medium supplemented with 1.5% loess the pellet size was reduced to a seventh compared to the control. In the case of addition of several insoluble salts, which are main components of loess, to the culture medium the higher concentrations of salts, the smaller sizes of pellet formed by the strain and the smallest pellet was formed by the addition of calcium sulfate.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.188-192
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• 1999

In order to minimize the mycelial pellet formation, one of the critical obstacles during the fermentation processes of filamentous fungi, an investigation was focused on the culture conditions(media and initial inoculum) and additives(soils, surfactants and polyethylene glycol 200) when a high phosphate-dissolving fungus, Penicillium sp. GL-101, was cultured in liquid media. Culturing the strain in PDB, SDB and YPD media, their pellet sizes decreased to the order of YPD > SDB > PDB. And at the high concentrations of the initial inoculum in the range from $1{\times}10^3\;to\;1{\times}10^6$ conidia/ml, the small sizes of pellet were formed in the PDB media. For the initial inoculum between $1{\times}10^7\;and\;1{\times}10^8$ conidia/ml, however, an amorphous pellet or loose aggregate was formed. The addition of soils, zeolite and diatomite, up to 1.0% decreased the pellet sizes to 3/4 and 1/2, respectively, but the pellet was increased to 2.5 times by the addition of bentonite. Surfactants also affected on the size of pellet; the addition of Triton X-100 and Tween 80 up to 1.0% decreased the pellet sizes maximally to 1/10 and 1/4, respectively, while SDS completely inhibited the fungal growth. Among the four additives tsted, polyethylene glycol 200 was the most effectively reduced the pellet sizes to $0.2{\pm}0.1$mm that resulted in about 25- fold reduction compared to the control.

• 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.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.132-139
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• 2005

The major obstacle in the popularization of Chungkookjang is the short shelf-life of $2{\sim}3$ months and some problems concerning storage including the growth of molds even in the products even within shelf-life. To solve these problems we conducted a research to improve its storage by using the vacuumed packaging and sanitary method through seed culture, innoculation and sterilization. For the optimization of storage time, temperature and sterilization temperature, we measured viable cell numbers of bacteria and fungi, amount of gas outbreak and contents of amino type nitrogen and monitored these experimental results by response surface methodology of SAS program, so that we could observe the quality changes of Chungkookjang during shelf-life. Especially fungi, which are the biggest troublemaker in Chungkookjang shelf-life, couldn't be detected from the generally and vacuum-packed samples; also, viable cell numbers were highly influenced by sterilization temperature and in vacuum-packed samples. In the case of vacuum-packed samples, amount of gas outbreak was highly influenced by sterilization temperature of its storage conditions and it was higher in generally packed samples as compared to vacuum-packed samples even at any storage conditions. The changes of pH in generally and vacuum-packed samples were highly influenced by the storage temperature. As the temperatures of storage and sterilization were higher and the storage time was longer, so the amount of gas outbreak was accordingly lower. These results showed that amino type nitrogen contents in generally and vacuum-packed samples were systematically influenced by the temperature, storage time and sterilization temperature. Also the result showed that the change of amino type nitrogen contents during storage was less in vacuum-packed samples than in general ones. Based on the above results, we can produce Chungkookjang products with extended shelf-life of as far as 6 months without any quality change using sanitary manufacturing method, vacuumed packaging condition, sterilization in $70^{\circ}C$ for 60 minutes and storage under $10^{\circ}C$ during shelf-life. According to this research, we have the possibility to greatly increase the goods value of Chungkookjang by developing the manufacture processing and packaging.