• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.202-210
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• 2022

Aflatoxin contamination in rice has been documented in a number of studies, and has a high incidence in Asian countries, and as such, there has been a growing interest in alternative biocontrol strategies to address this issue. In this study, 147 strains of yeasts and yeast-like fungi were screened for their potential to produce volatile organic compounds (VOCs) active against Aspergillus flavus strains that produce aflatoxin B₁ (AFB₁). Five strains within four different genera showed greater than 50% growth inhibition of some strains of A. flavus. These were Anthracocystis sp. DMKU-PAL124, Aureobasidium sp. DMKU-PAL120, Aureobasidium sp. DMKU-PAL144, Rhodotorula sp. DMKU-PAL99, and Solicococcus keelungensis DMKU-PAL84. VOCs produced by these microorganisms ranged from 4 to 14 compounds and included alcohols, alkenes, aromatics, esters and furans. The major VOCs produced by the closely related Aureobasidium strains were found to bedistinct. Moreover, 2-phenylethanol was the most abundant compound generated by Aureobasidium sp. DMKU-PAL120, while methyl benzeneacetate was the major compound emitted from Aureobasidium sp. DMKU-PAL144. On the other hand, 2-methyl-1-butanol and 3-methyl-1-butanol were significant compounds produced by the other three genera. These antagonists apparently inhibited A. flavus sporulation and mycelial development. Additionally, the reduction of the AFB1 in the fungal-contaminated rice grains was observed after co-incubation with these VOC-producing strains and ranged from 37.7 ± 8.3% to 60.3 ± 3.4%. Our findings suggest that these same microorganisms are promising biological control agents for use against aflatoxin-producing fungi in rice and other agricultural products.

• Journal of Practical Agriculture & Fisheries Research
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• v.14 no.1
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• pp.61-83
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• 2012

To identification of fungi that occurs round bale silages, 253 fungal contaminated samples were collected from 2009 to 2011. Total 253 silage samples from Italian ryegrass, sudan grass, rye, corn, barley and oat were analysed. Total 270 strains were purely isolated from contaminated round bale silages. The fungi were identified with morphological characteristics and rDNA sequence analysis. Nineteen species of fungi(Rhizopus sp., Fusarium spp., Coprinus sp., Blastomyces sp., Aureobasidium sp., Polypaecilum sp., Botryoderma sp., Mucor sp., Scytalidium sp., Sphaeropsis sp., Aspergillus spp., Trichocladium sp., Humicola sp., Staphylotrichum sp., Periconia sp., Verticillium sp., Diplococcium sp., Penicillium spp. and Trichoderma spp.) were identified by morphological characteristics. On the other hand, fungi isolated from silage were identified to Acremonium strictum, Aspergillus tubingensis, Bionectria ochroleuca, Dipodascaceae sp., Fusarium proliferatum, Fusarium oxysporum, Fusrium solani, Gelasinospora reticulata, Gibberella moniliformis, Gibberella zeae, Nectria mauritiicola, Penicillium paneum, Pseudallecheria boydii, Schizophyllum commune, Scopulariopsis brevicaulis and Simplicillium lamellicola by rDNA sequence analysis. Penicillium sp. and Trichoderma sp., were isolated 74 and 64 strains, respectively. Humicola sp., Aspergillus sp., Coprinus sp., and Fusarium spp. were identified 10 to 30 strains. Most fungi were isolated together with more than one species in a sample looked like one species with the naked eyes.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.63-68
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• 2009

The exo-polysaccharide producing microorganism, Aureobasidium pullulans IMS-822, was isolated and identified from soil. The viscosity-average molecular weight of exo-polysaccharide was calculated as $8.9{\times}10^5$ by Mark-Houwink equation. The sugar component of exo-polysaccharide was determined as glucose by HPLC analysis. The IR spectra indicated that the exo-polysaccharide has an absorption peak at 890 $cm^{-1}$ for the ${\beta}-configuration$ of D-glucan. The $^{13}C$ NMR signal at ${\delta}$ 86.62 ppm arose from the substituted C-3 of glucose. The signal at ${\delta}$ 72.11 ppm was assigned to C-6 of branched ${\beta}-(1{\to}3)-D-glucosyl$ residues. Viscosity and Congo red reaction indicated that {\beta}-(1{\to}3)(1{\to}6)-glucan$ produced by A. pullulans IMS-822 has a highly ordered hydrogen-bond dependent conformation in aqueous solution, which collapses in strong alkaline solution.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.342-345
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• 2000

Effect of volcanic ash on cell growth of Aspergillus sp. and production of exopolymers by Agrobacterium sp. and Aureobasidium pullualns was investigated. The volcanic ash contained various mineral salts such as $SiO_2$, $Al_2O_3$, CaO, $K_2O$. Maximal cell growth of Aspergillus sp. was obtained when 0.3% volcanic ash was added to medium. Cell growth of Aspergillus sp. increased with higher concentration of volcanic ash in medium. Amount of cell growth with 0.3 % volcanic ash was 6.7 times higher than that without volcanic ash. Volcanic ash also stimulated production of exopolymer as well as cell growth. Production of curdlan with 0.1% volcanic ash was 12.40 g/l whereas that without volcanic ash was 9.15 g/l. Production of pullulan with volcanic ash was also higher than that without volcanic ash.

• Journal of Sericultural and Entomological Science
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• v.24 no.1
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• pp.32-38
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• 1982

The study has been carried out to investigate a possibility to control the pine needle gall midge, Thecodiplosis japonensis Uchida et Inoue, by microbial pathogens as one of the microbial control measures. The samples were collected at Kocheon-Ri in the suburbs of Suweon city where were heavily damaged by this pest. Microorganisms were isolated from the both of diseased larvae and baiting method of soil microbes. In addition to, several species of the silkworm mucardine diseases were isolated for their infectivity of these fungi to the larvae of pine needle gall midge. Six species of fungi, Aureobasidium pullulans, Ascochyta sp, Verticillium psalliotae, Streptomyces sp., and two species of Aspergillus were isolated from the galls and soils, five species of muscardine diseases, Isaria farinosa, Spicaria pracina, Oospora destructor, Aspergillus flavus and A. oryzae were also identified from the silkworm corpse collected in the silkworm rearing farmers. Total of eleven species of fungi identified from the both of the larval of pine needle gall midge and silkworm larvae were tested for their pathogenecity to the larvae of pine needle gall midge. All of eleven species of fungi identified showed a considerable infectivity to the larvae. Twenty nine different kinds of bacteria were isolated from the both of diseased larvae and infested soils through the direct planting for the larvae and streaking for the corpse. The infectivity test is in progress. However two kinds of bacteria were recognized to be pathogenic to the larvae tested.

• Journal of Life Science
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• v.9 no.1
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• pp.69-80
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• 1999

Some trials to alter the structure of extracellular polysaccharides by means of biotransformation and microbial modification have been reported. Seaweed alginate was acetylated by intact and resting cells of Pseudomonas syringae ATCC 19304. Glucose analogs such as 3-O-methyl-D-glucose used as sole carbon sources was directly incorporated into curdlan by agrobacterium sp. ATCC 31749. The 2-amino-2-deoxy-D-glucose (glucosamine)and 2-acetamido-2-deoxy-D-glucose (N-acetylglucosamine) were incorporated into microbial cellulose by Acetobacter xylinum ATCC 10245. The changed monomeric composition in pullulan by Aureobasidium pullulans ATCC 42023 as well as zooglan by Zoogoea ramigera ATCC 25935 was another effect of glucose analogs used a carbon source. There was no effect of glucose analogs found in polysacharide-7 (PS-7) produced by Beijerinckia indica. ATCC 21423.

• Food Industry And Nutrition
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• v.2 no.1
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• pp.16-21
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• 1997

Microbial of enzymatical methods are suitable for production of rare monosaccharides. Using oxidation and reduction ability of Microorganisms, various rare ketoses and polyols can be produced, for example D-tagatose from galagtitol by Enterobacter agglomerans strain 221e. L-tagatose from galactitol by Klebsiella pheumonias strain 40b, L-psicose from allitol by Gluconobacter frateurii IFO 3254, D-talitol from d-tagatose by Aureobasidium pullulans strain 113B, allitol from D-psicose by Enterobacter agglomerans strain 221e and so on. We can produce various rare aldoses and ketoses using aldose isomerases, for example L-galactose from L-tagatose by D-arabnose isomerase, and L-ribose from L-ribulose by L-isomerase, and so on. D-Tagatose 3-epimerase of Pseudomonas sp. ST-24 is very useful for preparationof various rare ketoses, for example D-psicose from D-fructose, D-sorbose from D-tagatose, L-fructose, from L-psicose and so on. Using polyol dehydrogenases, aldose isomerases and D-tagatose 3-epimerase, we can design the suitable for production of a certain rare monosaccharide from a suitable substrate.

• The Korean Journal of Mycology
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• v.49 no.1
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• pp.67-79
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• 2021

This study aimed to isolate wild yeasts from waters and soils on the riversides of Geumgang upstream in Geumsan, seashores of Cheongpodae in Taean and Suncheonman in Suncheon, Korea, and to investigate their unrecorded microbiological characteristics. Forty-nine species of wild yeasts, including Aureobasidium pullans YH 4-3, were isolated from 40 samples of Cheonnaegang in Geumgang upstream. Fifty-six species and 36 species of wild yeasts were also isolated from 80 samples of Cheongpodae Beach and Suncheonman Mashland, respectively. Species from Candida genus were isolated from all three locations. Among them, Candida michaelii NNIBRFG28278, Sporobolomyces japonicus NNIBRFG28271, Dioszegia buhagiarii NNIBRFG28279, Ustilago spermophora NNIBRFG28273, Nakazawaea pomicola NNIBRFG31590, Candida natalensis NNIBRFG31591, Candida pseudorhagii NNIBRFG31592, Candida santamariae NNIBRFG31593, Cutaneotrichosporon terricola NNIBRFG31594, and Meira nashicola NNIBRFG31595 represent newly recorded yeast strains in Korea. Almost all of these unrecorded yeasts were oval shaped, and Sporobolomyces japonicus NNIBRFG28271 and Candida natalensis NNIBRFG31591 have ascospores. All the strains grew well in yeast extract-peptone-dextrose (YPD) and yeast extract-malt extract (YM) media, and Ustilago spermophora NNIBRFG28273 grew well in vitamin-free medium. Sporobolomyces japonicus NNIBRFG28271 grew well in 15% NaCl-containing YPD medium, and Ustilago spermophora NNIBRFG28273 and Dioszegia buhagiarii NNIBRFG28279 assimilated starch, and Ustilago spermophora NNIBRFG28273 produced ethanol.