• Journal of Microbiology
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• v.45 no.6
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• pp.521-527
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• 2007

Several yeast strains degrading malic acid as a sole carbon and energy source were isolated from Korean wine pomace after enrichment culture in the presence of malic acid. Among them, the strain designated as KMBL 5774 showed the highest malic acid degrading ability. It was identified as Issatchenkia orientalis based on its morphological and physiological characteristics as well as the nucleotide sequences of the internal transcribed spacer (ITS) 1-5.8S rDNA-ITS II region. Phylogenetic analysis of the ITS I-5.8S rDNA-ITS II sequences showed that the KMBL 5774 is the closest to I. orientalis zhuan 192. Identity of the sequences of the KMBL 5774 was 99.5% with those of I. orientalis zhuan 192. The optimal pH of the media for the growth and malic acid degradation by the yeast was between 2.0 and 3.0, suggesting that the strain is an acidophile. Under the optimized conditions, the yeast could degrade 95.5% of the malic acid after 24 h of incubation at $30^{\circ}C$ in YNB media containing 2% malic acid as a sole carbon and energy source.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.119-123
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• 1998

The feasibility of using combined treatments of electric field and chemical mutagen N-methyl-N'-nitro-N-nitroso-guanidine (NTG) for the strain improvement of Saccharomyces sp. in ethanol production was examined. The treatment of electric field alone resulted in no effect on the lethality of yeast cells under the conditions of this study. However, when the electric field was applied together to the treatment of yeast cells with NTG, the electric field increased the lethal effect and auxotrophic mutation rate of NTG. The combined treatment of electric field and NTG also increased the chances of. obtaining superior yeast strains for the ethanol production from tapioca. A higher number of improved clones was obtained by the combined treatments of electric field and NTG than by the NTG treatment alone. The best clone, NF 30-9, which was also obtained by the combined treatment, produced $11.07\%$ (w/v) ethanol from tapioca slurry containing 25% (w/v) reducing sugar while the parental strain produced 9.77% (w/v).

• Mycobiology
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• v.45 no.3
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• pp.199-203
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• 2017

This study was done to produce ${\gamma}$-aminobutyric acid (GABA) from wild yeast as well as investigate its anti-hyperglycemic effects. Among ten GABA-producing yeast strains, Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1 produced high GABA concentration of $134.4{\mu}g/mL$ and $179.2{\mu}g/mL$, respectively. P. silvicola UL6-1 showed a maximum GABA yield of $136.5{\mu}g/mL$ and $200.8{\mu}g/mL$ from S. carnicolor 402-JB-1 when they were cultured for 30 hr at $30^{\circ}C$ in yeast extract-peptone-dextrose medium. The cell-free extract from P. silvicola UL6-1 and S. carnicolor 402-JB-1 showed very high anti-hyperglycemic ${\alpha}$-glucosidase inhibitory activity of 72.3% and 69.9%, respectively. Additionally, their cell-free extract-containing GABA showed the anti-hyperglycemic effect in streptozotocin-induced diabetic Sprague-Dawley rats.

• Food Science and Preservation
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• v.10 no.3
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• pp.417-420
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• 2003

In order to study optimum culture condition of yeast medium added deep seawater, we examed samples with 9 yeast strains. The growth rate were measured for Saccharomyces cerevisiae 10, 11, 12, 901 and RCY and Saccharomyces kluyvery DJ97, Saccharomyces cerevisiae YJK, JK99, CMY-28 etc.. The growth of S. cerevisiae 12 was found most active in the deep seawater(hardness 500). The growth rate of S. cerevisiae 901 on medium containing deep seawater(hardness 1000) was faster than that of the yeast on medium without deep seawater. The use of deep seawater on the growth of Sacch.cerevisiae kluyvery DJ97 revealed maximum growth under the condition of hardness 200 of deep seawater and 10％ of sugar concentration.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.287-306
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• 2023

According to our previous study, 500 species of yeast exist in Korea, including nine variants comprising 142 genera and 48 classes in two phyla. Additionally, 4,483 fungal species have been documented at the National Institute of Biological Resources (NIBR). However, despite the industrial use of several yeasts, only 173 species formed part of the National Species List of Korea (NSLK) as of December 2021, mainly due to the lack of taxonomic descriptions. This study aimed to investigate the taxonomy of seven newly isolated yeast species (Hyphopichia burtonii, Starmerella sorbosivorans, Cyberlindnera mycetangii, Cutaneotrichosporon oleaginosum, Nakazawaea ernobii, Pichia kudriavzevii, and Schizosaccharomyces japonicus) for inclusion in the NSLK. The strains were clustered for the phylogenetic analysis of fungal rDNA (D1/D2-26S) sequences. This study provides descriptions of their cell morphology and physiological characteristics, the results of which confirm the indigenous origin of these seven species in Korea and recommend their inclusion in the NSLK.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.113-119
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• 1996

The ovipositional responses of two strains of the cigarette beetle, Lasioderma serricorne F., to thickness, of air- and flue-cured leaf tobacco were investigated. Eggs laid by the strains reared with wheatflour (95%) + yeast (5%) in the laboratory for several years were not different between air - and flue-cured tobacco leaves. There were negative correlations between grades of cured tobacco and ovipositional response, and the regression equation was Y(ovipositional response) : 58.22 - 10.15X(leaf grade). Adults of strains reared on tobacco leaves laid 161.00±80.29 eggs on the first grade of thick flue-cured leaves, and 7.67 ± 5.51 on the second grade of thin air-cured leaves. There was difference in ovipositional responses among different grades within variety, but significant differences were noted between thick and thin tobacco leaves. Key words : ovipositional response, cigarette beetle, Lasiodema sewicome F., tobacco.

• Archives of Pharmacal Research
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• v.11 no.1
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• pp.61-64
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• 1988

To investigate the antibiotic constituents of Korean basidiomycetes the carpophores of the wood-rotting basidiomycetes were collected from several locations of Korea, and from them 17 mycelial strains were isolated on potato-dextrose-agar plates supplemented with tetracycline ($20\;{\mu}g/m{\ell}$. The isolated strains were shake-cultured in glucosepeptone-yeast extract medium and then the antibacterial activities of the culture filtrates were assessed by disc-plate method. Among them, 12 strains (70.6%) were active, and basidiomycete strain LMCB-109 (Daedalea quercina) and LMCB-116 showed potent activities against all the six bacterial target organisms including Serratia marcescens.

• YAKHAK HOEJI
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• v.36 no.4
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• pp.345-349
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• 1992

Thymidylate synthase activity from extracts of various methotrexate-resistant strains was measured by spectrophotometric assay. Methotrexate-resistant strains of Lactobacillus, Pseudomonas sp., Micrococcus sp. HS-1, Klebsillela pneumonae, Cellulomonas fimi and Serratia marcescens elevated thymidylate synthase levels, especially, Pseudomonas sp. KL-9 resistant to $10^{-9}M$ methotrexate have a 156-fold increase in thymidylate synthase, which suggests that Pseudomonas sp. is a convenient source of thymidylate synthase. Several methotrexate strains of yeast were tested, however, their enzyme activity was generally lower than that of bacteria tested.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.403-415
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• 2018

The aims of this novel work were to determine the microbial strains and exopolysaccharide (EPS) producers in water kefir from Nakhon Ratchasima Province, Thailand. Thirty-three microbial strains were identified using 16S rRNA gene analysis consisting of 18 bacterial strains, as 9 strains of acetic acid bacteria (AAB), 9 strains of lactic acid bacteria (LAB), and 15 yeast strains. All bacteria were able to produce EPS with a diverse appearance on agar media containing different sugars at a concentration of 8%. Culture supernatants from AAB and LAB showed 31-64% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity with the highest antioxidant activity of 64% from Acetobacter pasteurianus WS3 and WS6. Crude EPS from A. pasteurianus WS3 displayed the highest ferric reducing antioxidant power at 280 mM $FeSO_4/g$ EPS, greatest anti-tyrosinase activity at 20.35%, and highest EPS production of 1,505 mg EPS/L from 8% sucrose. These microbes offer beneficial health implications and their EPSs can be used as food additives and cosmetic ingredients.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.75-82
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• 2018

Totally 91 strains of wild yeasts were isolated from the humus rich soil in the Bogyong city park of Daejeon city, Korea. Majority of the strains belonged to Cryptococcus spp., which included 11 strains of Cryptococcus aureus. Among them, Kwoniella mangroviensis JSS0500, Candida corydalis JSS0501, Candida bombi JSS0503, Candida multigemmis JSS0504, Cryptococcus dimennae JSS0506, Cryptococcus saitoi JSS0507, Cryptococcus victoriae JSS0508, Metschnikowia pulcherrima JSS0502, Papiliotrema aurea JSS0505, Debaryomyces vanrijia JSS0509, Occultifur externus JSS0510, Filobasidium floriforme JSS0511 and Yamadazyma scolyti JSS0512 represented newly recorded yeast strains in Korea, and their microbiological characteristics were investigated. All of these unrecorded yeasts showed oval shape and also formed ascospores and pseudomycelia, except for Kwoniella mangroviensis JSS0500, Candida bombi JSS0503, and Metschnikowia pulcherrima JSS0502. Seven strains including Candida corydalis JSS0501 grew in vitamin-free medium, and 4 of the wild yeasts including Cryptococcus victoriae JSS0508 were halotolerant, i.e., capable of growing in 10% NaCl-containing yeast extract-peptone-dextrose (YPD) broth. Debaryomyces vanrijia JSS0509 was found to be a thermophilic yeast that grew at $37^{\circ}C$.