• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.67-74
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• 1983

The studies on the color improvement of the Doenjang (two types of fermented soybean paste : soybean Doenjang and modified Doenjang) using various Aspergillus oryzae strains (6 strains : A, B, C, D, E, F) were conducted with the series of experiments of enzymatic activities (pretense, $\alpha$-and $\beta$-amylase), browning color formation (Lovibond color), major chemical components (amino nitrogen, reducing sugar and others) and sensory evaluation (color, taste and odor). Aspergillus oryzae 2157 (C strain) had a high potential for the color improvement of Doenjang products and was identified as non-browning strain during Doenjang fermentation and storage period. And also this strain was appeared to be in good enzyme activities and flavor characteristics.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.391-397
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• 1986

Three kinds of microoganisms were isolated and identified from the ginseng and ginseng products to research the properties of the molds which spoil the ginseng and ginseng products. The results obtained were as follows: (1) The predominant strains on ginseng products were Aspergillus sp., Penicillium sp.-A and Penicillium sp.-B. These predominant fungi deteriorated ginseng products exclusively, (2) Aspergillus sp. showed the greatest mycelial growth at $40^{\circ}C$ and its optimum pH was 5, meanwhile Pencillium sp. showed the greatest mycelial growth at $30^{\circ}C$ and its optimum pH was 3. (3) The growth of the isolated strains was stimulated with the increase in the concentration of saponin at the lower concentration, meanwhile it was inhibited at 1.0% concentration of saponin.

• The Korean Journal of Mycology
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• v.17 no.3
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• pp.154-160
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• 1989

The nuclear transfer technique was employed to obtain intraspecific hybrids in Aspergillus nidulans. Nuclei isolated from either a wild type or an auxotrophic mutant strain (FGSC 475) were transferred into the protoplasts of a recipient strain (FGSC 514). The frequency of hybrid formation (4.8% and 10.1 %, respectively) by nuclear transfer was higher than the frequency (0.6%) by protoplast fusion. Furthermore, most of the hybrids formed showed increased activity of some components of cellulase system, xylanase system, and mannanase. The hybrids were analyzed to be either diploid or aneuploid. These results suggest that nuclear transfer technique is more efficient the formation of intraspecific hybrids than protoplast fusion method and is useful for the improvement of Aspergillus strains.

• Mycobiology
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• v.44 no.3
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• pp.155-161
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• 2016

The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation. This study was performed to classify the most efficient strains of Aspergillus section Flavi isolated from various types of traditional wheat nuruk, based on a polyphasic approach involving molecular and biochemical evaluation. A total of 69 strains were isolated based on colony morphology and identified as Aspergillus oryzae/flavus based on internal transcribed spacer and calmodulin gene sequencing. Interestingly, none were toxigenic based on PCR amplification of intergenic regions of the aflatoxin cluster genes norB-cypA and the absence of aflatoxin in the culture supernatants by thin-layer chromatography analysis. Saccharification capability of the isolates, assessed through ${\alpha}-amylase$ and glucoamylase activities, revealed that two isolates, TNA24 and TNA15, showed the highest levels of activity. Although the degrees of variation in ${\alpha}-amylase$ and glucoamylase activities among the isolates were higher, there were only slight differences in acid protease activity among the isolates with two, TNA28 and TNA36, showing the highest activities. Furthermore, statistical analyses showed that ${\alpha}-amylase$ activity was positively correlated with glucoamylase activity (p < 0.001), and therefore screening for either was sufficient to predict the saccharifying capacity of the Aspergillus strain.

• Tuberculosis and Respiratory Diseases
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• v.77 no.5
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• pp.223-226
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• 2014

Aspergillus tracheobronchitis is a form of invasive pulmonary aspergillosis in which the Aspergillus infection is limited predominantly to the tracheobronchial tree. It occurs primarily in severely immunocompromised patients such as lung transplant recipients. Here, we report a case of Aspergillus tracheobronchitis in a 42-year-old man with diabetes mellitus, who presented with intractable cough, lack of expectoration of sputum, and chest discomfort. The patient did not respond to conventional treatment with antibiotics and antitussive agents, and he underwent bronchoscopy that showed multiple, discrete, gelatinous whitish plaques mainly involving the trachea and the left bronchus. On the basis of the bronchoscopic and microbiologic findings, we made the diagnosis of Aspergillus tracheobronchitis and initiated antifungal therapy. He showed gradual improvement in his symptoms and continued taking oral itraconazole for 6 months. Physicians should consider Aspergillus tracheobronchitis as a probable diagnosis in immunocompromised patients presenting with atypical respiratory symptoms and should try to establish a prompt diagnosis.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.258-267
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• 1973

Chemical analysis and enzymatic hydrolysis of certain Korean acorns were performed in order to make use of the local acorns. Exclusion of tannin from acorns is aided in the processing. Studies of these were undertaken and the results obtained are summarized as follows; 1. Several Korean acorns were used to analyze their proximate composition, tannin and major inorganic principles. The content of acorn tannin was found to be 6.5 to 7.5%. 2. An Attempt was made to screen suitable strains in order to make acorn-tannin-hydrolyzing enzyme accumulated in the culture broth, and Aspergillus flavus and Asp. sp. AN-11, which showed in their culture broths, were obtained from the contaminated acorns. 3. Cultural measures for the strains of Aspergillus flavus and Asp. sp. AN-11 for an improved tannase production and optimal conditions were determined.

• Journal of Food Hygiene and Safety
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• v.7 no.1
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• pp.15-22
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• 1992

This study was conducted to determine the potential of grapefruit seed extract to support Aspergillus parasilicus growth and aflatoxin production. The grapefruit seed extract inhibited the growth and aflatoxin production of the fungi in the level of more than 4,000 ppm and 3,000 ppm in the medium, respectively. Grapefruit seed extract appears to block the conversion of acetate, averufin and versiconal acetate into aflatoxin in vitro experiments. The addition of grapefruit seed extract to the feeding experiment systems did not inhibit the incorporation of 14C-labeled versicolorin A, versicolorin A hemiacetal and sterigmatocystin into aflatoxin. In the electron microscopic examination the biocidal action of grapefruit seed extract was related to the disturbance of cell menbrane funtion, inhibiting cellular respiration.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.477-481
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• 1992

As a series of fundamental research projects to produce doenjang (Korean fermented soy paste) of better quality, two kinds of doenjang were manufactured from a traditional meju (Korean soy bean koji) and the mixed with Aspergillus oryzae and Bacillus natto, and histological changes in the cell structures of soy bean of the two were reported doenjang samples were observed and compared during the entire period of fermentation processes. Cell walls of the soy bean were ruptured by pressure and heat during the pressure cooking process and some of them were observed to have the ghost-like shapes. Remarkable differences in the plasmolysis of the cytoplasms were observed between the seed coat and the inner part of soy bean. Small vacuoles resulting from the fusion of the glycoprotein globules by protease and from the hydrolysis of the starch granules by amylase were also observed. Penetration of microorganisms was transferred from the seed coat to the inside of soy bean as the fermentation proceeded. Slimy substances were observed on the seed coat and the parenchyma cells of soy bean fermented with the mixed with Aspergillus oryzae and Bacillus natto. Cell walls of soy bean became difficult to stain and they showed unusual, polygonal shapes as the fermentation proceeded. Samples fermented with the mixed with Aspergillus oryzae and Bacillus natto showed more remarkable tendencies than traditional meju.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.47-52
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• 1989

Aspergillus awamori, B-2 which has a high ability to decolorize melanoidin was selected among various fungi. Aspergillus awamori, B-2 showed the highest decolorization activity when it was cultivated in a melanoidin medium containing 3.0% glucose, 0.5% yeast extract, 0.1 % $KH_2PO_4\;and\;0.05%\;MgSO_4{\cdot}7H_2O$ at an initial pH 7.0 at $37^{\circ}C$ for 5 days. Mycelia immobilized system with. Ca-alginate was more effective on melanoidin decolorization activity showed approximately 70% in 10 days under the optimal conditions. Continuous decolorization of melanoidin using, reuse of immobilized mycelia showed an almost constant decolorization of abort 60-70% for 15 days.

• Mycobiology
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• v.46 no.1
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• pp.52-63
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• 2018

In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.