• Journal of Species Research
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• v.10 no.4
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• pp.336-343
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• 2021

In 2020, as a subset study to discover indigenous yeast species in Korea, a total of 22 yeast species were isolated from soil samples collected in Gwangju-si, Gyeonggi-do. Among them, 10 strains were unreported species. From the high 26S rRNA gene sequence similarity and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged independent and predefined yeast species. The 22 strains were assigned to the genera Dothiora (1 strain), Sarocladium (1 strain), Tetrapisispora (1 strain) and Torulaspora (2 strains) of the phylum Ascomycota; the genera Erythrobasidium (1 strain), Leucosporidium (4 strains), Ustilentyloma (2 strains), Fellozyma (1 strain), Sampaiozyma (2 strains), Filobasidium (1 strain), Solicoccozyma (2 strains) and Vishniacozyma (4 strains) of the phylum Basidiomycota. This is the first official report of the following species in Korea: Dothiora cannabinae (1 strain), Sarocladium strictum (1 strain), Fellozyma inositophila (1 strain), Filobasidium magnum (1 strain), Solicoccozyma phenolicus (1 strain), Solicoccozyma terreus(1 strain), Vishniacozyma tephrensis(1 strain) and Vishniacozyma victoriae (3 strains). Cell morphology, phenotypic features and biochemical features are described in the Species Description section.

• KSBB Journal
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• v.19 no.4
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• pp.245-249
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• 2004

A combined method of autolysis and enzymatic hydrolysis of baker's yeast was developed for the production of yeast extract, which is widely used as a natural food ingredient. From statistical analysis, NaCl and ethanol addition were found to be significantly effective factors in autolysis of yeast. The optimum dosages of salt and ethanol were 3% and 1%, respectively. Heat treatment and the use of cell lytic enzyme were not significantly effecting on the autolysis. Yeast hydrolysate was prepared by autolysis, followed by enzymatic hydrolysis using proteases, nuclease and deaminase. Additionally, the hydrolysate was processed by downstream process including Maillard reaction and debittering. The total dry matter yield and total nitrogen yield for the process were 76% and 59%, respectively. Compared to a process using brewer's yeast, when baker's yeast was used as a raw material, a higher recovery yield was obtained.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.147-152
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• 2000

For the probiotic feed production from residual food waste by using the yeast Kluyveromyces marxianus, aerobic liquid fermentation was attempted at $35^{\circ}C$. After grinding finely, optimal fermentation conditions of the substrate was investigated in shaking incubator. By controlling water content yeast growth was studied at each different solid content of 5, 10 and 15% respectively. The most active growth of the yeast was shown at 10%. For the stimulation of the cell growth, mixed culture with Aspersillus oryzae was conducted in a 2 litre-jar fermenter. As the results, the yeast growth rate was increased, but the maximum viable cell count amounted was slightly higher as $3.5{\times}10^9/ml$ than single culture.

• Journal of Microbiology
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• v.37 no.2
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• pp.51-58
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• 1999

Using yeast, Saccharomyces cerevisiae, and the integrate vector system, we have isolated and characterized an autonomously replicating sequence (ARS) from Aspergillus nidulans. The DNA fragment, designated ANR1, is 5.0 kb in size and maintained free from the chromosome in S. cerevisiae. The YIplac211-ANR1 recombinant plasmid, which consists of sequences derived from the yeast integrative vector YIplac211 and 5.0 kb ANR1 fragment, showed a 104-fold enhancement in transformation efficiency over that found for YIplac211, and was easily recovered from the transformed yeast. Genetic analysis of transformants showed that YIplac21-ANR1 could be over 96% cured when cultured over 20 generations in complete medium and thus suggests that this sequence is mitotically unstable. In A. nidulans, recombinant plasmid PILJ16-4.5 which carries the 4.5 kb EcoRI fragment of ANR1 showed a 170-fold enhancement in transformation efficiency compared to that of the integrative vector PILJ16.

• The Journal of Natural Sciences
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• v.4
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• pp.1-10
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• 1991

The expression of the cloned Saccharomyces cerevisiae antioxidant protein gene in E. coil on plasmid was studied. Introduction of the DNA encoding yeast thiol-specific antioxidant protein into expression vector, PKK 223-3, having the tac promoter resulted in the production in E. coil of a Mr 27,000 polypeptide. This protein represented as much as about 1% of the bacterial soluble protein and showed the thiol-specific antioxidant properties. The bacterial protein showed physico-chemical properties indistringuishable from those of the yeast protein.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.397-401
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• 1994

Bioreduction with active dried baker's yeast proceeded smoothly in n-hexane, pentane or petroleum ether as an organic solvent system. Ethyl(1) and octyl 3-oxohexanoate(2) were reduced to $({\underline{R}})-ethyl(3)$ and $({\underline{S}})-octyl$ 3-hyroxy-hexanoate(4) with high enantiomeric excess, respectively.

• 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.51 no.4
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• pp.373-381
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• 2023

This study aimed to isolate and characterize wild yeast strains from the vineyard soil in Korea. Twenty yeast strains were isolated from vineyard soil in Gimpo-si, Gyeonggi-do, Korea, where Vitis labrusca cv. Campbell Early is grown. Eighteen strains were previously recorded in Korea. The remaining two, Cyberlindnera mrakii VG-21-10C and Starmerella bacillaris GR9 were not previously recorded in Korea. The mycological characteristics of VG-21-10C and GR9 were investigated. Both were oval-shaped, convex, and smooth. However, differences were evident in colony color and carbon assimilation activities. Strain VG-21-10C is white-colored and assimilates glucose, glycerol, D-xylose, D-cellobiose, D-saccharose, and D-raffinose as carbon sources. Strain GR9 is cream-colored and assimilates glucose, D-saccharose, and D-raffinose as carbon sources.

• Journal of Species Research
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• v.13 no.2
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• pp.142-146
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• 2024

The purpose of this study was to isolate and identify wild yeasts from soil collected in Daegu City and Cheongyang County, Republic of Korea. Among 11 strains isolated in this study, nine strains were previously reported and two strains were unreported in Republic of Korea. To identify wild yeast strains, pairwise sequence comparisons of the D1/D2 region of the 26S rRNA gene sequence were done using Basic Local Alignment Search Tool (BLAST). The cell morphologies were observed by phase contrast microscope and assimilation test are done using API 20C AUX kit. All strains were assigned to the phylum Basidiomycota. Of the two unrecorded yeast strains, CY-9-10C belongs to the genus Mrakia (family Mrakiaceae, order Cystofilobasidiales, class Tremellomycetes) and PG3-4-10C belongs to the genus Slooffia (family Chrysozymaceae, order Microbotryomycetes incertae sedis, class Microbotryomycetes). Both strains had oval-shaped and polar budding cells. This research described the morphological and biochemical properties of the two unreported yeast species that had not officially reported in Korea.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.555-564
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• 2019

Biodiesel is produced through the transesterification process in the presence of alcohol and a catalyst that catalyzes the conversion of triglycerides to esters and glycerol compounds. A more optimal product conversion can be achieved using enzymes, such as lipase. Lipase is reported to be produced in osmophilic yeasts due to the low water content in their natural habitats. Wild forest honey is one of the osmophilic natural habitats in Indonesia. However, lipase-producing yeast has not been reported in the Indonesian honey. In this study, we screened the lipase-producing yeasts isolated from wild forest honey collected from Central Sulawesi. The production profile and activity of lipase were determined at different pH values and temperatures. One promising yeast was isolated from the honey, which was identified as Zygosaccharomyces mellis SG 1.2 based on ITS sequence. The maximum lipase production (24.56 ± 1.30 U/mg biomass) was achieved by culturing the strain in a medium containing 2% olive oil as a carbon source at pH 7 and 30℃ for 40 h. The optimum pH and temperature for lipase activity were 6 and 55℃, respectively. The enzyme maintained 80% of its activity upon incubation at 25℃ for 4 h. However, the enzyme activity decreased by more than 50% upon incubation at 35 and 40℃ for 2 h. This is the first study to report the lipase producing capability of Z. mellis. Further studies are needed to optimize the enzyme production.