• Journal of Microbiology
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• 제44권6호
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• pp.674-679
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• 2006

Biodiversity of yeasts was investigated in the ginseng cultivation field. Among 34 isolates tested in this study, 26 isolates belonged to the hymenomycetous yeast group. These 26 strains were classified into 12 species including four new-species candidates that did not have clear affiliation to any established species. Seven isolates among the remaining strains were classified into three ascomycetous yeast species, and one isolate was identified as a urediniomycetous yeast species.

• 한국균학회지
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• 제51권4호
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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.

• Mycobiology
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• 제43권4호
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• pp.458-466
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• 2015

Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis.

• 한국균학회지
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• 제48권4호
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• pp.475-484
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• 2020

국내에 서식하는 꽃에서 다양한 토착 효모를 분리 및 확보하고 효모의 분포 특성과 종 다양성에 관해 연구하였다. 국내 25지역에서 꽃 9종 77개체를 채집한 후 효모를 순수분리하였다. 효모 502균주의 large-subunit (LSU) rDNA 염기서열을 분석 및 상동성 비교로 각 효모의 종을 동정하였다. 분리된 효모는 총 50종으로 동정 되었고, 모든 꽃 시료로부터 Aureobasidium pullulans, A. leucospermi, Filobasidium magnum이 분리되었다. 꽃에 우점한 효모 3종을 제외하고, 효모 균주 수가 적게 분리된 종은 지역과 분리원에 따른 유의성을 확인할 수는 없었다. 본 연구를 통해 꽃으로부터 확보한 국내 토착 효모 50종은 산업적 활용을 위한 자원으로써 역할을 기대할 수 있고, 추후 효모와 기주 간의 상호작용이나 효모다양성 연구의 기초자료로써 활용될 수 있을 것이다.

• Journal of Microbiology and Biotechnology
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• 제22권7호
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• pp.960-966
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• 2012

The diversity and composition of yeast populations may greatly impact wine quality. This study investigated the yeast microbiota in two different types of wine fermentations: direct inoculation of a commercial starter versus pied de cuve method at an industrial scale. The pied de cuve fermentation entailed growth of the commercial inoculum used in the direct inoculation fermentation for further inoculation of additional fermentations. Yeast isolates were collected from different stages of wine fermentation and identified to the species level using Wallersterin Laboratory nutrient (WLN) agar followed by analysis of the 26S rDNA D1/D2 domain. Genetic characteristics of the Saccharomyces cerevisiae strains were assessed by a rapid PCR-based method, relying on the amplification of interdelta sequences. A total of 412 yeast colonies were obtained from all fermentations and eight different WL morphotypes were observed. Non-Saccharomyces yeast mainly appeared in the grape must and at the early stages of wine fermentation. S. cerevisiae was the dominant yeast species using both fermentation techniques. Seven distinguishing interdelta sequence patterns were found among S. cerevisiae strains, and the inoculated commercial starter, AWRI 796, dominated all stages in both direct inoculation and pied de cuve fermentations. This study revealed that S. cerevisiae was the dominant species and an inoculated starter could dominate fermentations with the pied de cuve method under controlled conditions.

• Animal Bioscience
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• 제36권1호
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• 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.

• 한국식생활문화학회지
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• 제34권2호
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• pp.201-207
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• 2019

This review summarizes the studies on a wide variety of yeast found in kimchi and the effects of yeast on kimchi fermentation, and discusses the direction for further research. Yeast belongs to the genera Trichosporon, Saccharomyces, Sporisorium, Pichia, Lodderomyces, Kluyveromyces, Candida, Debaryomyces, Geotrichum, Kazachstania, Brassica, Yarrowia, Hanseniaspora, Brettanomyces, Citeromyces, Rhodotorula, and Torulopsis have been identified using culture-dependent methods and metagenomics analysis. The application of yeast as a starter into kimchi has resulted in an extension of shelf life and improvement of sensory characteristics due to a decrease in the amount of lactic acid. On the other hand, some yeast cause kimchi spoilage, which typically appears as an off-odor, texture-softening, and white-colony or white-film formation on the surface of kimchi. In contrast to lactic acid bacteria, there are limited reports on yeast isolated from kimchi. In addition, it is unclear how yeast affects the fermentation of kimchi and the mechanism by which white colony forming yeast predominate in the later stage of kimchi fermentation. Therefore, more research will be needed to solve these issues.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1373-1381
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• 2022

Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.