• The Korean Journal of Mycology
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• v.47 no.1
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• pp.51-61
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• 2019

The goal of this study was to elucidate wild yeast diversity of Geumgang midstream near Sejong metropolitan autonomous city, Korea. Thirty-seven strains of 32 species of wild yeasts were isolated from 43 water and soil samples under the Bulti bridge of Sejong city, Korea. Seven yeasts of each Candida spp. and Cryptococcus spp. were the predominant species isolated from samples near the Bulti bridge. Holtermanniella takashimae SW048 (NNIBRFG9314), Cystofilobasidium infirmominiatum SW013 (NNIBRFG9310), Mrakia cryoconite SW015 (NNIBRFG9316), Pichia sporocuriosa SW085 (NNIBRFG9326) and Cryptococcus aspenensis SW008 (NNIBRFG9309) represented novel yeast strains found in Korea for the first time. All of these previously unrecorded yeasts, except for Mrakia cryoconite SW015 had ascospores and grew well in yeast extract-peptone-dextrose (YPD), yeast extract-malt extract (YM) and potato-extrose (PD) media. Pichia sporocuriosa SW085 grew well in vitamin-free medium and Holtermanniella takashimae SW048, which was a halotolerant wild yeast, grew well YPD medium containing 5 % NaCl. Twenty-six strains representing eight species of wild yeast were isolated from 22 water and soil samples under the Haetmuri bridge of Sejong city, Korea. Candida pseudolambica (12 strains) and Aureobasidium pullulans (11 strains) were the predominant isolates from samples near the Haetmuri bridge. Occultifur kilbournensis HB060 (NNIBRFG9317), Sampaiozyma vanillica HB014 (NNIBRFG9332), Xenoramularia neerlandica HB039 (NNIBRFG9335), Candida norvegica HB315 (NNIBRFG9306), C. melibiosica HB316 (NNIBRFG9305), C. quercuum GB014 (NNIBRFG9307), and C. succiphila GB015 (NNIBRFG9308) represented novel yeast strains recorded in Korea for the first time. O. kilbournensis HB060 and X. neerlandica HB039 did not form ascospores or pseudo-mycelia. All of these previously unrecorded yeasts, except S. vanillica HB014 and X. neerlandica HB039, grew well in vitaminfree medium, and C. norvegica HB315 and C. succiphila GB015, which were halotolerant wild yeasts, which grew well in YPD medium containing 5 % NaCl.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.44-44
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• 2014

Yeasts were isolated from wild flowers of some islands and mountains such as Jeju-do, Ulleungdo, Yokjido, Seonyudo and Gyejoksan, Oseosan, Beakamsan and Deogyusan in Korea and were identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA or internal transcribed pacer(ITS) 1 and 2 including 5.8S rDNA using BLAST. Seventy two yeast strains of two hundred eighty nine species were isolated from wild flowers in islands and mountains, Korea. Among them, Cryptococcus species were isolated the most dominantly, and Metschnikowia reukaufii were also isolated thirty species, 10.3% of total strains. Twenty-three species including Cryptococcus aureus were overlapped between yeast strains of the islands and mountains. Some physiological functionality of the culture broth and cell-free extracts from two hundred eighty nine yeast strains were determined. The supernatant of Candida sp. 78-J-2 showed antioxidant activity of 22.5%, and supernatant of Metschnilowia reukaufii SY44-6 showed anti-gout xanthine oxidase inhibitory activity of 49.6% and whitening tyrosinase inhibitory activity of 38.4%, respectively.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1749-1757
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• 2012

Makgeolli is a traditional rice wine favored by the general public in Korea. This study investigated the fermentation and sensory characteristics of using wild yeast strains for brewing makgeolli. A non-Saccharomyces cerevisiae strain was isolated from nuruk and termed Y197-13. It showed 98% similarity to Pichia anomala and had an optimal growth temperature of $25^{\circ}C$. Makgeolli was manufactured using koji, jinju nuruk, and improved nuruk as fermentation agents. Y197-13 makgeolli brewed with koji had alcohol and solids contents of 11.1% and 13.9%, respectively. Sweet sensory characteristics were attributed to residual sugars in makgeolli with 6% alcohol. The makgeolli had a fresh sour taste and carbonated taste. Volatile component analysis showed the isoamyl alcohol, phenylethyl alcohol, isoamyl acetate, and fatty acid, including ethyl oleate and ethyl linoleate, relative peak area was higher in Y197-13 makgeolli than in makgeolli with Saccharomyces cerevisiae. These results suggest the wild yeast, Y197-13, as a candidate for brewing makgeolli.

• Journal of Species Research
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• v.12 no.3
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• pp.197-202
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• 2023

The purpose of this study was to isolate and identify wild yeasts from the soil collected in Gwangju and Pocheon City, Gyeonggi Province, Republic of Korea. Among 10 strains, six strains were already reported, but four strains were unrecorded in Republic of Korea. To identify wild yeast strains, pairwise sequence comparisons of the D1/D2 region of the 26S rRNA gene sequence were performed using Basic Local Alignment Search Tool (BLAST). The cell morphologies were observed by phase contrast microscope and assimilation tests were carried out using API 20C AUX kit. The 10 strains were assigned to the phyla Basidiomycota (8 strains) and Ascomycota (2strains). The unrecorded four yeast strains, NH33, NH19, NH20, and YP416, belong to the phylum Basidiomycota and the genera Buckleyzyma, Leucosporidium, Holtermanniales, and Mrakia, respectively. All strains had oval-shaped and polar budding cells. In this research, the morphological and biochemical properties of four unreported yeast species were characterized intensively, which were not officially reported in Korea.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.315-323
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• 2018

The goal of this study was to isolate wild yeasts from the fields of medicinal plants and investigate its tyrosinase inhibitory activities. Wild yeasts isolated from soil in the ginseng and Korean angelica fields of Geumsan, Chungcheongnam-do, Korea were identified by comparing the nucleotide sequences of the D1/D2 domain of 26S rDNA. In total, 43 yeast strains belonging to 21 species were isolated from 50 soil samples obtained from two medicinal plant fields. From the ginseng field, six strains of Rhodotorula glutinis and four strains of Sampaiozyma ingeniosa were isolated, out of which Rhodotorula glutinis strains were dominant. In the Korean angelica field, six strains of Cyberlindnera saturnus, three strains of Piskurozyma taiwanensis, and three strains of Saitozyma podzolica were isolated, out of which Cyberlindnera saturnus strains were dominant. We prepared cell-free extracts of the isolated wild yeasts and their tyrosinase inhibitory activities were investigated. Among 43 yeast strains, cell-free extracts of Naganishia globosa G1-7 showed the highest tyrosinase inhibitory activity (28.0%).

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.15-18
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• 1998

The entanol productivity of superoxide dismutase (SOD)-deficient mutants of Saccharo-Myces cerevisiae was examined under the oxidative stress by Paraquat. It was observed that MnSOD-deficient mutant of S. cerevisiae had higher ethanol productivity than wild type or CuZnSOD-deficient yeast both in aerobic and in anaerobic culture condition. Pyruvated dehydrogenase activity decreased by 35% and alcohol dehydrogenase activity increased by 32% were observed in MnSOD-deficient yeast grown aerobically. When generating oxygen radicals by Paraquat, the ehanol productivity was increased by 40% in CuZnSOD-deficient or wild strain, resulting from increased activity of alcohol dehydrogenase and decreased a activity of pyruvate dehydrogenase. However, the addition of ascorbic acid with Paraquat returned the enzyme activities at the level of control. These results imply that SOD-deficiency in yeast strains may cause the metabolic flux to shift into anaerobic ethanol fermentation in order to avoid their oxidative damages by Paraquat.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.361-371
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• 2023

The study was undertaken to isolate and characterize wild yeast strains from soil samples collected in Seoul, Korea. Among the 19 yeast strains obtained, 17 were previously recorded species. The remaining two strains, Wickerhamomyces sp. GW1-4 and Archaeorhizomyces sp. YB4-103 were new species candidates. The genomic and microbiological characteristics of GW1-4 and YB4-103 were investigated. Phylogenetic analyses based on the 26S rRNA gene sequences and internal transcribed sequences, GW1-4 and YB4-103, represent a distinct lineage within the family Phaffomycetaceae and Archaeorhizomycetaceae, respectively. The GW1-4 and YB4-103 strains had the highest sequence homology with Wickerhamomyces xylosivorus NBRC 111553^T (88.97%) and Archaeorhizomyces finlayi CBS 128710^T (87.55%), respectively.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.237-249
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• 2020

The goal of this study was to isolate wild yeasts from waters and soils in Sangjubo of Nakdong river and Daechung dam in Daejeon city, Korea and investigate characteristics of previously unrecorded novel wild yeasts. In total, 94 strains from 39 different species of wild yeasts were isolated from 47 soils and waters samples obtained from Sangjubo in Nakdong river. Among these, 3 strains, including Rhodosporidium azoricum JSL-GRU-009, represented novel yeast strains which were previous recorded. Two hundred nine strains from 105 different species of wild yeasts were isolated from 130 soils and water samples obtained from Daechungdaegyo and Daechung dam of Shintanjin in Daejeon city, Korea. Ten strains including Bullera pseudoalba JSL-GRU-005 also represented newly recorded strains in Korea. All the 13 previously unrecorded yeasts were oval or global in shape, and nine strains, including R. azoricum JSL-GRU-009, formed ascospores. Ten strains grew well in vitamin-free medium. R. azoricum JSL-GRU-009 grew well in 20% glucose-containing yeast extract-peptone-dextrose (YPD) medium and 3 strains, including Rhodotorula oryzicola JSL-GRU-003, grew well in 5% NaCl-containing YPD medium.

• The Korean Journal of Mycology
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• v.43 no.1
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• pp.64-67
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• 2015

Several kinds of wild yeasts were isolated and identified from some cereals. A total of twenty six yeast strains were isolated from eleven kinds of cereals. Among twenty six yeast strains, Saccharomyces cerevisiae were five strains and Pseudozyma antarctica were four strains. Five species of Cryptococcus including Cryptococcus magnus were also isolated. Pseudizyma aphidis were isolated from black bean, and Saccharomyces cerevisiae, Cryptococcus flavescens, Cryptococcus magnus and Hannaella zeae were also isolated from glutinous millet.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.337-349
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• 2021

This study aimed to isolate wild yeasts from water and soil sample of the Nonsan stream and Sapgyoho (lake) in Chungcheonnam-do, Korea, and to further characterize previously unrecorded wild yeast strains. In total, 102 strains, representing 55 different species of wild yeast were isolated from 95 samples collected from the Jangseoncheon and Ipchoncheon of Nonsan stream in Jellabuk-do and Chungcheonnam-do. Among these, 33 strains were isolated from alkalophilic yeast extract-peptone-dextrose (YPD) medium (pH 9.0), and 9 strains were isolated concurrently on general YPD medium (pH 6.5) and alkalophilic medium. Seventeen strains of Cryptococcus laurentii were predominantly isolated. Additionally, 65 strains, representing 27 different species of wild yeast were isolated from 58 samples obtained from Sapgyoho (lake). Among the 82 isolated wild yeast strains, 8 strains, including Candida fructus JSC 72-1(JSL-GGU 015), had not previously been recorded. All 8 previously unrecorded yeasts were oval in shape except C. fructus JSC72-1(JSL-GGU-015), and only the Filobasidium chernovii JSC39-1(JSL-GGU-013) strain formed spores. All strains except Pseudosydowia eucalypti JSC23-6(JSL-GGU-012) grew well in yeast extract-peptone-dextrose (YPD) and yeast extract-malt extract media and grew in vitamin-free medium. Four strains, including P.eucalypti JSC23-6(JSL-GGU-012) grew well in 15% NaCl-containing YPD medium. F.chernovii JSC39-1(JSL-GGU-013) and Sirobasidium intermedium JSC7-3(JSL-GGU-014) assimilated lactose, and five strains, including F. chernovii JSC39-1(JSL-GGU-013) also assimilated starch. All strains were resistant to 800 ppm of Ca, Cu, Li, and Mg ions.