• Journal of Food Hygiene and Safety
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• v.7 no.1
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• pp.1-6
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• 1992

Two Rice cultivars , a high yield variety of Cheongcheong and a Korea native kind of Chucheong were grown in paddy. 1$\mu\textrm{g}$ and 10$\mu\textrm{g}$ of aflatoxin B1 and Aspergillus flavus (106 conidia/ml) were inoculated at milk stage. At harvest, kernels from the inoculated plant showed slightly lower ripening rates and 100-grain weight than did those of controls. The nutrient and fatty acid composition of unpolished rice of inoculated group were similar to those of controls and difference between the control and inoculated group were not significantly different.

• Korean Journal of Microbiology
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• v.9 no.3
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• pp.130-138
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• 1971

In order to investigate the production of aflatoxin in various conditions such as pH, moisture and temperature, 27 smaples were inoculated with Aspergillus flavus, and in addition 3 smaples were inoculated with the mixture of Aspergillus flavus and Bacillus subtilis and cultured under the conditions such as 20.deg.C and 30% moisture contents. The following results were obtained : 1) Aflatoxin production was the highest at pH 5.0 and relatively high at pH 7.0. Its production was decreased significantly when pH reached 9.0. 2) The yield of aflatoxin was shown comparatively high level at 30% moisture contens. The higher moisture contents was, the lower aflatoxin production was. 3) The highest level of aflatoxin production was at 20.deg,C, and comparatively high level was at 30.deg.C. However, its production was fairly low at 40.deg.C. 4) The highest crude aflatoxin production was 5,093ppm (B$_{1}$, 1.912ppm ; B$_{2}$, and the lowest one 2.197 ppm (B$_{1}$, 0.793 ppm : B$_{2}$, 0.185 ppm : G$_{1}$ ,0.102 ppm G$_{2}$, 0.381ppm) at 63% moisture, pH 9.0 and 40.deg.C. 5) When Aspergillus flavus and Bacillus subilis were cultured together under the conditions such as 20.deg.C and 30% moisture, aflatoxin production was decreased by 27% comparing with the culture of Aspergillus flavus alone.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.737-746
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• 1995

Through the study of identification of filamentous molds isolated from 12 traditional Nuruk, collected from several regions in Korea, 78 strains of Absidia spp., including Absidia corymbifera, Absidia ramosa, and Absidia sp. of which specific names were not identified, 19 strains of Rhizopus spp. including Rhizopus cohnii, Rhizopus arrhizus, and Rhizopus oryzae, 8 strains of Circinella spp., 1 strain of Actinomucor sp., 49 strains of Aspergillus spp., including Aspergillus oryzae, Aspergillus flavus, Aspergillus flavus var. columnaris, Aspergillus wentii, Aspergillus candidus, Aspergillus fumigatus, Aspergillus niger, and Aspergillus foetidus, 2 strains of Cladospoyium spp. and 2 strains Botryotrichum spp., etc. total 159 kinds of filamentous molds were isolated and identified. There were many differences in numbers and distributions of filamentous molds from each Nuruk according to their collected region. Absidia spp. were most frequently isolated from every Nuruk sample. Aspergillus oryzae, Aspergillus candidus, and Rhizopus cohnii showed even distribution. Penicillium sp. and Mucor sp. were not detected. Actinomucor sp., Aspergillus foetidus, Botryotrichum sp., and Cladosporium spp., which have not been reported by far, were found. Amylase activities, pH stability of amylase, and acid productivity of isolated strains were compared.

• Mycobiology
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• v.33 no.2
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• pp.84-89
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• 2005

Five types of agricultural wastes were used for the production of xylanolytic enzyme by Aspergillus flavus K-03. All wastes materials supported high levels of xylanase and ${\beta}-xylosidase$ production. A high level of proteolytic activity was observed in barley and rice bran cultures, while only a weak proteolytic activity was detected in corn cob, barley and rice straw cultures. Maximum production of xylanase was achieved in basal liquid medium containing rice barn as carbon source for 5 days of culture at pH 6.5 and $25^{\circ}C$. The xylanolytic enzyme of A. flavus K-03 showed low thermostability. The times required for 50% reduction of the initial enzyme activity were 90 min at $40^{\circ}C$, 13 min at $50^{\circ}C$, and 3 min at $60^{\circ}C$. Xylanolytic activity showed the highest level at pH $5.5{\sim}10.5$ and more than 70% of the original activity was retained at pH 6.5 and 7.0. The higher stability of xylanolytic enzymes in the broad range of alkaline pH is useful for utilization of the enzymes in industrial process requiring in alkaline conditions. Moreover, the highest production of xylanolytic enzyme was obtained when 0.5% of rice bran was supplied in basal liquid medium. SDS-PAGE analysis revealed a single xylanase band of approximately 28.5 kDa from the culture filtrates.

• Journal of Environmental Health Sciences
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• v.16 no.1
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• pp.45-53
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• 1990

To investigate the effect of cultural condition on the aflatoxin production of Aspergillus flayus ATCC 15517, mixed culture with Aspergillus niger, better kind of media and size of Cultural vessels were examined. YES medium was better than SLS medium for this study. Small scale test tube culture was showed the possibility to simply examine the growth, total acidity, pH and aflatoxin production during cultivation, and also could reduce the second contamination of aflatoxin B1 from large scale broth cultured. Especially ELISA method is simple, sensitive and specific and therefore well suited to small scale of test tube culture. Mixed culture significantly reduced the aflatoxin production of Aspergillus fiavus ATCC 15517 and showed almost 95% inhibition of that level during the incubtation.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.389-393
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• 2003

The essential oils from Cedrus atlantica, Styrax tonkinensis, Juniperus communis, Lavandula angustifolia, Melaleuca alternifolia, Pelargonium graveolens, Pogestemon patchouli and Rosmarinus officinalis were analyzed by GC-MS. Antifungal activities of the oils were investigated by disk diffusion assay and the broth dilution method against Aspergillus niger and A. flavus. The effects of geraniol and the essential oil fraction from P. graveolens on the antifungal activity of amphotericin Band ketoconazole were examined using a checkerboard microtiter assay against both Aspergillus fungi. Most of the tested essential oils, with the exception of C. atlantica, J. communis, and P. patchouli, significantly inhibited growth of A. niger and to a lesser extent that of A. fIavus, with MICs (minimal inhibitory concentrations) in the range 0.78-12.5 mg/mL. The essential oil fraction of P. graveolens and its main components, geraniol and citronellol, exhibited additive effects with amphotericin B and with ketoconazole against both Aspergillus species, resulting in fractional inhibitory concentration (FIC) indices ranging from 0.52 to 1.00.

• The Korean Journal of Mycology
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• v.1 no.1
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• pp.17-21
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• 1973

Fifty-eight strains of Aspergillus spp. isolated from various grains were examined for the screening of aflatoxins by the method of the Thin-Layer Chromatography (TLC), using the aflatoxin producing strain of Aspergillus flavus ATCC 15517 as a control. The results as follows: 1. Samples of Aspergillus spp. isolated from various grains were extracted with chloroform and chromatographied by the thin-layer chromatography method. 2. Three strains of Aspergillus spp. among the 58 strains can be found that the spots having the same Rf value as control with culture extract of Aspergillus flavus ATCC 15517. 3. The further prove studies of aflatoxins were proceed by the methods of in vivo and in vitro tests. And this methods considered to capable for the use of mass screening among the samples.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.303-313
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• 2021

Peanuts in storage were estimated for mycotoxigenic fungi and mycotoxins. Peanut samples collected from storages in Gochang were mainly contaminated with Fusarium (17.2±28.0%), Penicillium (12.4±28.0%), and Aspergillus (8.0±7.6%). Other genera, including Talaromyces, Rhizopus, Rhizoctonia, Trichocladium, Clonostachys, Mucor, Chaetomium, Trametes, Epicoccum, and Humicola, were also found. Although aflatoxins were not detected in the peanut samples, 29 strains of Aspergillus flavus were identified using molecular marker genes. Among them, 17 selected isolates produced aflatoxins in solid culture media ranging from 0.61-187.82 ㎍/kg. All of them could produce both aflatoxin B₁ and B₂ and some (n=5) produced additional G₁, G₂, or both. This study is the first report that A. flavus stains obtained from Korean stored peanut are aflatoxigenic.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.25-25
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• 2014

Koji molds are comprised of yellow, black and white. Black and white koji molds were recently re-visited by this author and it is concluded that they consists of Aspergillus luchuesnsis, A. niger and A. tubingensis, and the most important species for alcoholic beverage production is A. luchuensis. In the case of yellow koji mold, it is comprised of Aspergillus oryzae, A. sojae and A. tamari. In the case of A. sojae, the species is scarcely isolated from nature and rarely used for industry in Korea. Aspergillus tamari is often isolated from traditional Korean Meju, a fermented soybean product, and the classification of the species is clear. However, in the case of A. oryzae, differentiation between A. oryzae and A. flavus is still in controversy. In this study, we collected 415 strains of Aspergillus flavus/oryzae complex from air, rice straw, soybean, corn, peanut, arable soil and Meju in Korea and we examined the aflatoxin producing capacity of the strains. The norB-cypA, omtA and aflR genes in the aflatoxin biosynthesis gene cluster were analyzed. We found that 367 strains (88.4%) belonged to non-aflatoxigenic group (Type I of norB-cypA, IB-L-B-, IC-AO, or IA-L-B- of omtA, and AO type of aflR), and only 48 strains (11.6%) belonged to aflatoxin-producible group (Type II of norB-cypA, IC-L-B+/B- or IC-L-B+ of omtA, and AF type of aflR). In the case of A. flavus/oryzae strains from Meju, almost strains (178/192, 92.7%) belonged to non-aflatoxigenic group and only 14 strains (7.3 %) belonged to aflatoxin-producible group. It is proposed in this study that non-aflatoxigenic strain from Meju is classified as A. oryzae, considering that Meju is food material.

• Korean Journal of Microbiology
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• v.17 no.1
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• pp.16-24
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• 1979

In order to investigate the production of aflatoxin in various conditions such as pH, moisture and temperature, 27 smaples were inoculated with Aspergillus flavus, and in addition 3 smaples were inoculated with the mixture of Aspergillus flavus and Bacillus subtilis and cultured under the conditions such as $20^{\circ}C$ and 30% moisture contents. The following results were obtained : 1) Aflatoxin production was the highest at pH 5.0 and relatively high at pH 7.0. Its production was decreased significantly when pH reached 9.0. 2) The yield of aflatoxin was shown comparatively high level at 30% moisture contens. The higher moisture contents was, the lower aflatoxin production was. 3) The highest level of aflatoxin production was at $20^{\circ}C$, and comparatively high level was at $30^{\circ}C$. However, its production was fairly low at $40^{\circ}C$. 4) The highest crude aflatoxin production was 5,093ppm $(B_1,\;1.912\;ppm;\;B_2,\;0.521\;ppm;\;G_1,\;2.119\;ppm;\;G_2,\;0.541\;ppm)$ at 30% moisture, pH 5.0 and $20^{\circ}C$ and the lowest one 2.197 ppm $(B_1,\;0.793\;ppm;\;B_2,\;0.185\;ppm;\;G_1,\;0.102\;ppm;\;G_2,\;0.381\;ppm)$ at 63% moisture, pH 9.0 and $40^{\circ}C$ 5) When Aspergillus flavus and Bacillus subilis were cultured together under the conditions such as $20^{\circ}C$ and 30% moisture, aflatoxin production was decreased by 27% comparing with the culture of Aspergillus flavus alone.