• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1781-1786
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• 2011

This study was conducted to investigate the cause of microbiological contamination in yogurt and evaluate the effect of physicochemical treatment on the growth inhibition of Hanseniaspora uvarum isolated from yogurt. The yeast strain Hanseniaspora uvarum Y1 was subjected to heat and pH treatments. H. uvarum Y1 was killed at $70^{\circ}C$ and $80^{\circ}C$ after 15 min and survived in a wide pH range from pH 2 to 9. However, it did not survive under pH 1 and over pH 10. In a disk diffusion susceptibility test on H. uvarum Y1, a clear zone (5 mm) of growth inhibition was observed upon treatment with electrolyzed water. The effect of ozone gas on the growth of H. uvarum Y1 was evaluated by viable cell count. Initial cell numbers of $10^2$ and $10^3$ CFU/mL of H. uvarum Y1 were completely killed by treatment for 10 and 30 min, respectively. H. uvarum Y1 was also sterilized by microwave treatment for 1 min. When treated with gamma-irradiation, the rate of killing of H. uvarum Y1 was proportional to the irradiation dose. and complete killing occurred at a dose of 50 kGy.

• The Korean Journal of Mycology
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• v.42 no.1
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• pp.21-27
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• 2014

Several kinds of yeasts from fruits and flowers of orchard in Yesan-gun of Chungcheongnam-do, Korea were isolated and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Fourty eight yeast strains of twenty five species and one hundred eight yeast strains of fourty eight species were isolated from fruits and flowers of orchard in Sinam-myeon of Yesan-gun, Chungcheongnam-do, respectively. Among total one hundred fifty-six yeast strains, only sixteen species were overlapped from fruits and flowers.

• 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.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.185-191
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• 2013

Several yeast colonies were isolated from wild flowers collected from East, West and South coast areas of Korea by plating of flower suspensions on the YPD plates containing antibiotics, streptomycin and ampicillin. Polymerase chain reactions (PCR) were performed for the amplification of D1/D2 region of 26S rDNA for those colonies. PCR-amplified nucleotide sequences were compared using BLAST for their identification. As results, 27 yeast strains belonged to 15 species were isolated from wild flowers collected at Donghae, where is located in eastern coast of Korea. Also, 34 strains belonged to 17 species were isolated from wild flowers of Daecheon, where is located in western coast of Korea. In addition, 22 strains belonged to 13 species were isolated from wild flowers collected at Wando, where is located in southern coast of Korea. Among those 45 species isolated from 3 different collection sites, only 4 species including Cryptococcus laurentii, Metschnikowia koreensis, Pseudozyma rugulosa, and Rhodotorula mucilaginosa were found from all 3 different collection sites. And 5 species including Cryptococcus aureus, Cryptococcus flavus, Hanseniaspora uvarum, Pichia guilliermondii, and Rhodosporidium fluviale were overlapped from the at least 2 different collection sites. Other 23 species were found only in a specific collection sites implying that each area has distinctive yeast flora.