• 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.46 no.4
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• pp.447-457
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• 2018

In this paper, the screening of potent acetylcholinesterase (AChE) inhibitor - producing yeasts from wild yeasts and the condition for the production of anti-dementia AChE inhibitors are described. Among one hundred and seven non-pathogenic wild yeast strains from the waters and soils of three main rivers in Daejeon metropolitan city and midstream of Yeongsangang river in Sangju, sporogenous Saccharomyces cerevisiae WJSL0113 and asporogenous Wickerhamomyces anomalus JSF0128 were selected as useful strains for the production of potent AChE inhibitors. The AChE inhibitors of S. cerevisiae WJSL0113 and W. anomalus JSF0128 had a maximum yield when they were incubated in yeast extract-peptone-dextrose media (pH 6.0 in S. cerevisiae WJSL0113 and pH 5.0 in W. anomalus JSF0128) for 18 hr at $30^{\circ}C$, respectively.

• Journal of Life Science
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• v.22 no.1
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• pp.110-116
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• 2012

Nuruk plays a significant role in the flavor and quality of Takju and Yakju, which are produced through saccharification and alcohol fermentation by various microorganisms. In this study, we identified microbial strains isolated from a plate count and PCR-denaturing gradient gel electrophoresis (DGGE) analysis targeting the 16S and 28S rRNA genes, in order to characterize bacterial and fungal diversity in Sansung Nuruk. The numbers of bacteria and fungi in Nuruk were $1.5{\times}10^9$ CFU/g and $2.2{\tims}10^8$ CFU/g, respectively. The 16S rRNA gene sequence indicated that the predominant bacteria in the isolates and PCR-DGGE profile of Nuruk were Kocuria spp., Pantoea spp., Lactobacillus spp., Pediococcus spp., Weissella spp., Staphylococcus spp., endophytic bacterium, uncultured Gamma-proteobacteria, uncultured Cyanobacteria, and Actinobacteria. Dominant bacteria from the PCR-DGGE profile were Pediococcous pentosaceus and uncultured Cyanobacteria. The 28S rRNA gene sequence indicated the predominant fungi in the isolates and PCR-DGGE profile to be Trichomonascus spp. Pichia spp., Torulaspora spp., Wickerhamomyces spp., Sacharomycopsis spp., Lichtheimia spp., Mucor spp., Rhizopus spp. Aspergillus spp., and Cladosporium spp. Dominant fungi from the PCR-DGGE profile were Pichia kudriavzevii and Aspergillus oryzae. The PCR-DGGE technique was used for the first time in this study to assess a microbial community in Nuruk and proved to be an effective protocol for profiling microbial diversity.

• The Korean Journal of Mycology
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• v.52 no.1
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• pp.1-11
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• 2024

The present study aimed to screen unrecorded wild yeasts from Jeju lsland and Jangsado on the southern coast of Korea, and to investigate their microbiological characteristics. To date, Coniozyma leucospermi JJD37-2, Hanseniaspora thailandica JJD44-1, Kluyveromyces nonfermentans JJD15-1, Kockovaella fuzhouensis JJD47-3, Vishniacozyma heimaeyensis JJD8-4, Candida carpophila JSDH24-1, Wickerhamomyces strasburgensis JSDH34-2, Candida savonica HJD6-4, and Candida karawaiewii YP23-3 have not been previously recorded in Korea. In the present study, we investigated the microbiological characteristics of these previously unrecorded yeasts. Except for W. strasburgensis JSDH34-2 strain, none of the strains formed spores, and only the C. leucospermi JJD37-2 strain formed pseudomycelia. Almost all strains grew well in yeast extract-peptone-dextrose (YPD) medium, potato dextrose (PD) medium and yeast extract-malt extract (YM) media. C. carpophila JSDH24-1 and W. strasburgensis JSDH34-2 also grew well in YPD medium containing 10% NaCl. H. thailandica JJD44-1 is fermented to produce glucose, fructose and mannose.

• Mycobiology
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• v.39 no.1
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• pp.33-39
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• 2011

Wild yeasts on the surface of various fruits including grapes were surveyed to obtain yeast strains suitable for fermenting a novel wine with higher alcohol content and supplemented with rice starch. We considered selected characteristics, such as tolerance to alcohol and osmotic pressure, capability of utilizing maltose, and starch hydrolysis. Among 637 putative yeast isolates, 115 strains exhibiting better growth in yeast-peptone-dextrose broth containing 30% dextrose, 7% alcohol, or 2% maltose were selected, as well as five ${\alpha}$-amylase producers. Nucleotide sequence analysis of the 26S rDNA gene classified the strains into 13 species belonging to five genera; Pichia anomala was the most prevalent (41.7%), followed by Wickerhamomyces anomalus (19.2%), P. guilliermondii (15%), Candida spp. (5.8%), Kodamaea ohmeri (2.5%), and Metschnikowia spp. (2.5%). All of the ${\alpha}$-amylase producers were Aureobasidium pullulans. Only one isolate (NK28) was identified as Saccharomyces cerevisiae. NK28 had all of the desired properties for the purpose of this study, except ${\alpha}$-amylase production, and fermented alcohol better than commercial wine yeasts.

• The Korean Journal of Mycology
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• v.51 no.1
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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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• v.27 no.8
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• pp.1409-1418
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• 2017

Two typical microbial communities from Chinese rice wine fermentation collected in Yichang city and Suzhou city in China were investigated. Both communities could ferment glutinous rice to rice wine in 2 days. The sugar and ethanol contents were 198.67 and 14.47 mg/g, respectively, for rice wine from Yichang city, and 292.50 and 12.31 mg/g, respectively, for rice wine from Suzhou city. Acetic acid and lactic acid were the most abundant organic acids. Abundant fungi and bacteria were detected in both communities by high-throughput sequencing. Saccharomycopsis fibuligera and Rhizopus oryzae were the dominant fungi in rice wine from Suzhou city, compared with R. oryzae, Wickerhamomyces anomalus, Saccharomyces cerevisiae, Mucor indicus, and Rhizopus microsporus in rice wine from Yichang city. Bacterial diversity was greater than fungal diversity in both communities. Citrobacter was the most abundant genus. Furthermore, Exiguobacterium, Aeromonas, Acinetobacter, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were highly abundant in both communities.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.350-354
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• 2016

Diverse wild yeast were isolated from freshwaters and soils of Nakdong and Yeongsan rivers in Korea and identified by the comparison of polymerase chain reaction-amplified nucleotide sequences of the internal transcribed spacer region (including the 5.8S rRNA) and D1/D2 regions of 26S rDNA, using BLAST. In total, 15 strains belonging to 9 species were isolated from 25 samples, out of which Aureobasidium pullulans and Cryptococcus bestiolae were dominant. Candida ghanaensis JSF0127 and Meira geulakonigii JSF0130 were identified as unrecorded yeasts, for which their mycological characteristics were investigated. These unrecorded yeasts formed ascospores and grew in yeast extract peptone dextrose medium containing 5% NaCl.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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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.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.56-64
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• 2015

It has been known for some time to the wine industry that non-Saccharomyces yeasts play an important role in increasing volatile components through the secretion of extracellular enzymes. The objective of this study was to investigate what types of enzymes are produced by 1,007 non-Saccharomyces yeast strains isolated from Korean fermented foods. Among 1,007 yeast strains, the 566, 45 and 401 strains displayed β-glucosidase, glucanase and protease activity, respectively. In addition, the 563 and 610 strains possessed tolerances against cerulenin and TFL, and the 307 strain was tolerant to 15% ethanol. Yeasts producing harmful biogenic amines and hydrogen sulfide were excluded from further study, and eventually 12 yeast strains belonging to the genera Wickerhamomyces, Hanseniaspora, Pichia, Saccharomyces were identified, based on the 26S rRNA gene sequences. Among the 12 strains, the 9 and 5 strains possessed glucose and ethanol tolerance, respectively. Yeasts belonging to the genus Saccharomyces produced more than 8% alcohol, but non-Saccharomyces yeasts produced only 3% alcohol.