• 한국환경농학회지
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• 제34권3호
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• pp.238-243
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• 2015

BACKGROUND: Yeasts associated with fleabane flowers were identified using isolation methods previously applied in yeast biotechnology. A culture-based approach was required for isolation of many yeast strains associated with fleabane. METHODS AND RESULTS: We spread homogenized fleabane flowers onto GPY medium containing chloramphenicol, streptomycin, Triton X-100, and L-sorbose. We isolated 79 yeast strains from the flowers of wild fleabane, and identified the yeasts via phylogenetic analysis of isolates from agar plates. The yeast species included 39 isolates of Aureobasidium pullulans, 17 of the genus Candida, 14 of the genus Rhodosporidium, 6 of the genus Cryptococcus, and 3 of the genus Rhodotorula. CONCLUSION: Yeast isolates associated with fleabane flowers included A. pullulans (39 isolates) and other yeast species (40 isolates). Such yeast isolates may have biotechnological potential.

• 한국균학회지
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• 제45권4호
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• pp.259-269
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• 2017

대전광역시 하천들의 효모 종 다양성을 조사하기 위하여 먼저 대전광역시 동남부와 시내를 흐르는 대전천과 서남부의 갑천에 있는 물과 주변 토양들을 2016년 8월과 2017년 2월에 각각 148점을 동일 장소에서 채취하여 야생효모들을 분리, 동정하였다. 여름 채취 물과 주변 토양 74점에서 23종 37균주의 야생효모들이 분리된 반면에 겨울 채취 시료들에서는 약 2배 이상 많은 34종 83균주가 분리되었다. 이들 3대 하천에서 가장 많이 분리된 야생효모는 Candida속 균으로 전체 42%이었고 Cryptococcus속 균과 식품에서 주로 분리되는 Saccharomyces속 균들이 각각 7%와 6%로 많이 분리되었다. 종 수준에서는 Candida tropicalis가 25균주로 가장 많았으며 여름 시료와 겨울 시료에서 공통으로 분리된 효모들은 Aureobasidium pullulans 등 13종이었다.

• Journal of Species Research
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• 제9권3호
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• pp.198-203
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• 2020

The goal of this study was to isolate and identify wild yeasts from soil samples. The 15 wild yeast strains were isolated from the soil samples collected in Pocheon city, Gyeonggi Province, Korea. Among them, four yeast stains were unrecorded, and 11 yeast stains were previously recorded in Korea. To identify wild yeasts, microbiological characteristics were observed by API 20C AUX kit. Pairwise sequence comparisons of the D1/D2 domain of the 26S rRNA were performed using Basic Local Alignment Search Tool(BLAST). Cell morphology of yeast strains was examined by phase contrast microscope. All strains were oval-shaped and polar budding and positive for assimilation of glucose, 2-keto-ᴅ-gluconate, N-acetyl-ᴅ-glucosamine, ᴅ-maltose and ᴅ-saccharose (sucrose). There is no official report that describes these four yeast species: one strain of the genus Kodamaea in the family Metschnikowiaceae and three strains of the Hannaella in the family Bulleribasidiaceae. Kodamaea ohmeri YI7, Hannaella kunmingensis YP355, Hannaella luteola YP230 and Hannaella oryzae YP366 were recorded in Korea, for the first time.

• 한국균학회지
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• 제50권1호
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• pp.65-73
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• 2022

본 연구는 남해안 해운대와 인근 몽돌해수욕장 주변의 야생 효모 종 분포특성을 알아보기위해 이들 지역 주변의 물과 모래, 토양 등 70점의 시료들로부터 일반 효모와 호알칼리성 균주 등 모두 37종, 41균주의 야생 효모들을 분리하였다. 이들 야생 효모들 중 Cys. insectorum HUD16-3 (JSLKSS-002)와 M. citriensis HUD12-5 (JSL-KSS-001)등 두 균주들이 국내 보고되지 않은 미기록 효모들로 선별되었고 필자 등이 전라북도 장선천 주변 토양에서 분리하여 국내 미기록 균주로 선별한 Cys. lysinophilum JSC 52-2 (JSL-GGU-019)와 대전광역시 장태산 호수 주변에서 분리하여 선별한 C. takata NMD11-1 (JSL-GGU-017), C. panamensis ASG58M-2 (JSL-GGU-018)등 5종의 미기록 야생 효모들의 균학적 특성을 조사하였다. 이들 미기록 효모들은 모두 난형으로 출아에 의해 영양 증식을 하였고 포자와의 균사를 형성하지 않았다. 미기록 효모 모두 vitamin-free배지에서도 생육하였고 M. citriensis HUD12-5균주는 50% 포도당을 함유한 YPD배지에서 생육하는 강한 내당성을 보였고 Cys. insectorum HUD16-3과 M. citriensis HUD12-5균주들은 15% NaCl을 함유한 YPD배지에서도 생육이 비교적 양호한 호염성균이었다 또한, 미기록 효모들 모두 포도당과 fructose, sucrose, 전분 등을 자화시켰고 특히Cys. lysinophilum JSC 52-2등 3균주들은 lactose를 자화시켰다.

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.846-853
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• 2016

We displayed four types of Solanum nigrum metallothionein (SMT) for the first time on the surface of Saccharomyces cerevisiae using an α-agglutinin-based display system. The SMT genes were amplified by RT-PCR. The plasmid pYES2 was used to construct the expression vector. Transformed yeast strains were confirmed by PCR amplification and custom sequencing. Surface-expressed metallothioneins were indirectly indicated by the enhanced cadmium sorption capacity. Flame atomic absorption spectrophotometry was used to examine the concentration of Cd²⁺ in this study. The transformed yeast strains showed much higher resistance ability to Cd²⁺ compared with the control. Strikingly, their Cd²⁺ accumulation was almost twice as much as that of the wild-type yeast cells. Furthermore, surface-engineered yeast strains could effectively adsorb ultra-trace cadmium and accumulate Cd²⁺ under a wide range of pH levels, from 3 to 7, without disturbing the Cu²⁺ and Hg²⁺. Four types of surfaceengineered Saccharomyces cerevisiae strains were constructed and they could be used to purify Cd²⁺-contaminated water and adsorb ultra-trace cadmium effectively. The surface-engineered Saccharomyces cerevisiae strains would be useful tools for the bioremediation and biosorption of environmental cadmium contaminants.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.219-224
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• 1992

식염농도 3로$15^{\circ}C$에서 발효시킨 물김치에서 젖산균과 효모의 균수변화를 측정한 결과 숙성기까지 효모의 수가 증가한 후 후기에 감소하는 것으로 나타났으며 숙성적기에 효모를 분리동정한 결과 Saccharomyuces sp.가 24주로 대부분을 차지하였으나 Kluyveromyces fragilis 3주, Torulopsis candida 2주도 발견되었다. 이 중에서 S.saitoanus Y17, S.capensis Y29, S.chevalieri Y13, K.fragilis Y2, T.candida Y9를 같은 김치에서 분리한 젖산균 Lactobaccillus plan tarum Lp2, Pediococcus pentosaceus P1, Leuconostoc mesentroides Lu5와 각각 혼합배양하여 효모와 생육에 미치는 영향을 조사한 결과 모두 생육이 억제되었으며, 이는 lacti acid나 H2O2에 의한 억제가 아닌 다른 물질에 의한 것으로 밝혀졌다. 이 세 종류의 젖산균에 의해 영향을 받는 정도는 효모의 종류에 따라 매우 큰 차이를 나타내었다.

• 한국균학회지
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• 제49권4호
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• pp.545-553
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• 2021

In 2021, seven yeast strains were isolated from earthworm (Eisenia andrei) gut samples collected from the Nanji Water Regeneration Center in Goyang City, Gyeonggi Province, Korea. A total of seven yeasts were isolated, of which three strains have not been previously reported in Korea. To identify the yeasts, pairwise sequence comparisons of large subunit (LSU) rDNA sequences were performed using the basic local alignment search tool (BLAST). Assimilation test and cell morphology analysis were performed using the API 20C AUX kit and phase contrast microscope, respectively. Five of the seven strains were assigned to the genus Candida of the order Saccharomycetales of the class Saccharomycetes, and two to the genus Apiotrichum of the order Trichosporonales of the class Tremellomycetes. The yeast strain Candida sojae E2 belongs to the family Debaryomycetaceae, and Apiotrichum laibachii E8 and A. laibachii E9 belong to the family Trichosporonaceae. All strains were cultured in yeast mold agar for three days and showed different colony forms. C. sojae E2 was round and entire shaped, while A. laibachii E8 and A. laibachii E9 was round and convex shaped. This study focuses on the description of the three yeast strains that have not been officially reported in Korea.

• 한국균학회지
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• 제51권1호
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• pp.7-24
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• 2023

More than five hundreds of yeast species (including 9 variants) encompassing 142 genera and 48 classes of 2 phyla exist in Korea. However, only 173 species have been cataloged in the National Species List of Korea (NSLK), the backbone reference to claim sovereign rights over biological resources, as of December 2021, due to the lack of taxonomic descriptions, although some of these species are extensively used in industry. The present pilot study investigated the taxonomy of strains belonging to the six most widely used or frequently isolated yeast species (Meyeromyma guilliermondii, Saccharomyces cerevisiae, Saccharomycopsis fibuligera, Wickerhamomyces anomalus, Candida tropicalis, and Papiliotrema flavescens) to include these species in the NSLK. Strains with diverse habitats and geographic origins were retrieved from the National Institute of Biological Resources culture collection. These strains clustered in the same clade as the type strains of the designated species according to phylogenetic analysis of the D1/D2 sequences. Moreover, we described the cell morphology and physiological characteristics of representative strains of each species. This study suggests that these six species are indigenous to Korea and can be accordingly listed in the NSLK.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1891-1907
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• 2016

Yeasts that are present in marine environments have evolved to survive hostile environments that are characterized by high exogenous salt content, high concentrations of inhibitory compounds, and low soluble carbon and nitrogen levels. Therefore, yeasts isolated from marine environments could have interesting characteristics for industrial applications. However, the application of marine yeast in research or industry is currently very limited owing to the lack of a suitable isolation method. Current methods for isolation suffer from fungal interference and/or low number of yeast isolates. In this paper, an efficient and non-laborious isolation method has been developed and successfully isolated large numbers of yeasts without bacterial or fungal growth. The new method includes a three-cycle enrichment step followed by an isolation step and a confirmation step. Using this method, 116 marine yeast strains were isolated from 14 marine samples collected in the UK, Egypt, and the USA. These strains were further evaluated for the utilization of fermentable sugars (glucose, xylose, mannitol, and galactose) using a phenotypic microarray assay. Seventeen strains with higher sugar utilization capacity than the reference terrestrial yeast Saccharomyces cerevisiae NCYC 2592 were selected for identification by sequencing of the ITS and D1/D2 domains. These strains belonged to six species: S. cerevisiae, Candida tropicalis, Candida viswanathii, Wickerhamomyces anomalus, Candida glabrata, and Pichia kudriavzevii. The ability of these strains for improved sugar utilization using seawater-based media was confirmed and, therefore, they could potentially be utilized in fermentations using marine biomass in seawater media, particularly for the production of bioethanol and other biochemical products.

• Journal of Microbiology and Biotechnology
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• 제32권7호
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• pp.877-884
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• 2022

Probiotics are microorganisms that can benefit host health when ingested in a live state, and lactic acid bacteria are the most common type. Among fungi, Saccharomyces boulardii (SB) is the only strain known to have a probiotic function with beneficial effects on colitis; however, information on other probiotic yeast strains is limited. Therefore, this study aimed to discover yeast strains expressing intestinal anti-inflammatory activities by exhibiting probiotic properties in dextran sodium sulfate (DSS)-induced colitis mice model. Nuruk (Korean traditional fermentation starter) containing various microbial strains was used as a source for yeast strains, and S. cerevisiae 28-7 (SC28-7) strain was selected with in vitro and in vivo characteristics to enable survival in the intestines. After 14 days of pretreatment with the yeast strains, DSS was co-administered for six days to induce colitis in mice. The results revealed that the disease activity index score was lowered by SC28-7 treatment compared to the DSS group, and the colon length and weight/length ratio were recovered in a pattern similar to that of the normal group. SC28-7 administration significantly reduced the secretion of pro-inflammatory cytokines in the serum and modified the mRNA expression of inflammatory cytokines (interleukin-1β, transforming growth factor-β, and interferon-γ) and proteins involved in gut barrier functions (mucin 2, mucin 3, zonula occludens-1, and occludin) in colon tissues. These results indicate that SC28-7 attenuates DSS-induced colon damage and inflammation, supporting its future use as a probiotic yeast for treating and preventing intestinal inflammatory diseases such as inflammatory bowel disease.