• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.410-416
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• 2000

Changes in microflora and enzyme activities of three kinds of kochujang were investigated during 6 months of fermentation. Three different kinds of kochujang were prepared using Aspergillus oryzae, Aspergillus oryzae plus Bacillus licheniformis and Aspergillus oryzae, Bacillus licheniformis plus Saccharomyces rouxii. The pH of kochujang showed a slight decrease during fermentation. The number of mold and bacteria increased up to 30 days of fermentation and then decreased rapidly thereafter and the numbers of yeast increased after 30 days of fermentation. The viable cell counts of anaerobic bacteria increased remarkably up to 30 days of fermentation and then decreased to 60 days of fermentation. The activities of ${\alpha}-$, ${\beta}-\;amylase$ and protease were the highest in kochujang prepared with Aspergillus oryzae plus Bacillus licheniformis.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.568-574
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• 1991

The cloned glyceraldehyde-3-phosphate dehydrogenase (GAP) gene of Saccharomyces cereviszae (Holland et al., 1983) has been characterized. Based on the communication, we have also cloned 2.1 kb CAP DNA fragment and modified this fragment as a portable promoter. Two yeast expression vectors, one is YCp type vector being maintained at low copy number (1 or 2) and the other is YEp type vector at high copy number, have been constructed with the GAP promoter and the PH05' gene as a reporter. Our plasrnids were introduc,ed into S. cerevisiae HY-1, which has been improved. The $Trp^+$ transformants expressed APase activity efficiently and showed high level of PH05' transcripts.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.923-927
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• 2005

ln order to develop yeast cells that produce a bacteriocin on their cell surfaces, the 114 bp Leucocin A gene with stop codon was ligated into pYDl, an yeast vector. The recombinant DNA, pYDl-LeucoA was used to transform yeast (Saccharomyces cerevisiae) cells. Yeast cells harboring pYDl-LeucoA showed antibacterial activity against Bacillus subtilis. To confirm these bacteriocidal yeast cells possess the Leucocin A gone, PCR was performed with plasmid prepared from transformed yeast cells as a template and two Leucocin A-specific primers. In this study, bacteriocidal yeast cells that can be used as an antibiotic or a food preservative were developed.

• Food Science and Preservation
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• v.10 no.1
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• pp.89-93
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• 2003

To develope natural food preservatives, ethanol and water extracts were prepared from the Lentinus edodes and antimicrobial activities were examined against 10 microorganisms which were food borne pathogens and / or food poisoning microorganisms and food-related bacteria and yeasts. Ethanol extract exhibited antimicrobial activities for the microorganisms tested, but not on lactic acid bacteria and yeast Especially, minimum inhibitory concentration(MIC) for Escherichia coli were as low as 0.5 mg/mL. Antimicrobial activity of the ethanol extract was stable by the heating at 121$^{\circ}C$ for 15 min and not affected by pH. The ethanol extract of Lentinus edodes exhibiting high antimicrobial activity. The highest antimicrobial activity adjust bacteria tested was found in the ethylacetate fraction.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.50-54
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• 1998

Ethyl caproate is one of the important flavor compounds produced during the brewing of rice wine. The rice wine yeast and koji were reported to produce the esterases which synthesize and also hydrolyze ethyl caproate. From the results of monitoring the esterase activities of rice wine yeast and koji, their roles for producing ethyl caproate during brewing were postulated. In case of rice wine yeast, the production of esterase synthesizing ethyl caproate was influenced by the substrate, caproate but that of esterase hydrolyzing ethyl caproate was promoted by ethyl caproate but inhibited by caproate. The production of esterases of koji were not influenced by the substrates for ethyl caproate production but influenced by the growth of koji. The maximum concentration of ethyl caproate produced by rice wine yeast was 0.4 ppm in this research but the production of ethyl caproate by koji was not detected under our experimental conditions. Considering the results of this research, ethyl caproate is not produced by the esterases of koji during brewing but produced by the esterases of rice wine yeast. The growth of rice wine yeast represses that of koji because of the high concentration of ethanol produced by rice wine yeast. The esterases of rice wine yeast may decide the production of ethyl caproate during brewing.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.1-5
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• 1990

This study was performed to isolated woild killer yeasts which might suppress the growth of contaminant yeasts during wine making. Seventeen strains of killer yeasts which were isolated from grapes in Korea showed different killing activity; higher with K109 and K112. and lower with K117 strain. There was no inhibition among the isolates by cross-reaction. Through the physiological, morphological and cultural test, the isolates were identified as a new killer yeast, Cadida dattila, and then named Candida dattila K101-K117.

• 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.46 no.3
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• pp.315-323
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• 2018

The goal of this study was to isolate wild yeasts from the fields of medicinal plants and investigate its tyrosinase inhibitory activities. Wild yeasts isolated from soil in the ginseng and Korean angelica fields of Geumsan, Chungcheongnam-do, Korea were identified by comparing the nucleotide sequences of the D1/D2 domain of 26S rDNA. In total, 43 yeast strains belonging to 21 species were isolated from 50 soil samples obtained from two medicinal plant fields. From the ginseng field, six strains of Rhodotorula glutinis and four strains of Sampaiozyma ingeniosa were isolated, out of which Rhodotorula glutinis strains were dominant. In the Korean angelica field, six strains of Cyberlindnera saturnus, three strains of Piskurozyma taiwanensis, and three strains of Saitozyma podzolica were isolated, out of which Cyberlindnera saturnus strains were dominant. We prepared cell-free extracts of the isolated wild yeasts and their tyrosinase inhibitory activities were investigated. Among 43 yeast strains, cell-free extracts of Naganishia globosa G1-7 showed the highest tyrosinase inhibitory activity (28.0%).

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.199.1-199
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• 2003

제주민속주인 좁쌀약주의 제조를 위하여 전국에서 수집된 35종의 누룩으로부터 우수 곰팡이와 효모를 분리하였다. 수집된 누룩의 균수는 곰팡이가 6.4$\times$105~107개, 효모는 1.4$\times$104~107개로 나타났고, 이 중에서 곰팡이 169균주, 효모 103균주를 분리하였으며 전분당화력이 좋은 곰팡이 16균주와 효모 1균주를 선발하였다. 이 중에서 전분당화 균주의 효소활성을 분석한 결과 Aspergillus속으로 동정된 A8-3이 glucoamylase 활성, 액화력, xylanase 활성이 가장 높았고, Rhizopus속으로 동정된 B23-3은 당화력이 가장 우수하였다. 우수효모를 선발하기 위하여 pH, 무게 감량, 내당성, 내알코올성 등을 측정한 결과, Saccharomyces속인 A10-4가 가장 우수하였다. 같은 원료비율로 만든 누룩에 우수균주를 접종하였을 때, 단일 균주를 처리할 때보다 A8-3과 B23-3인 두 균주를 혼합하여 처리한 경우가 당화력이 높게 나타났다. 누룩을 원반형의 누룩과 팰릿(개량형) 형태로 만들어 혼합종균 배양액을 접종한 후 당화력을 측정한 결과, 비슷한 당화력을 나타내었다. 개량형 누룩을 사용하여 양조하는 경우, 좁쌀주 양조에 발효효율을 높일 수 있을 것으로 판단되었다. 수집된 누룩은 수분이 10~13%, 총당은 55~70%, 조단백질은 10~18% 조지방은 0.2~l.0%, 회분은 1.8~2.1%이었다. 본 연구에서 제조한 누룩은 수분이 12~15%, 총당은 61~7l%, 조단백질은 15~20%, 조지방은 0.4~1.5%, 회분은 1.1~1.5%이었다.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.249-258
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• 2019

The goal of this study was to isolate and characterize the wild yeast strains in the soils of Hajodae and Gyungpodae Beaches, Gyungpo Lake in Kangwon-do, Korea and evaluate their anti-demential and tyrosinase inhibitory activities. Among the 27 yeast strains isolated from 30 soil samples from Hajodae Beach, Cyberlindnera culbertsonii HJ31-1, Dothichiza pithyophila HJ22-4, Metschnikowia bicuspidata HJ16-1, and Sakaguchia cladiensis HJ14-1 were recorded for the first time in Korea. Additionally, six of the 55 wild yeast strains isolated from 45 soil samples from Gyungpodae Beach and Gyungpo Lake had not previously been detected in Korea, such as Aureobasidium melanogenum JR3-1. The microbiological characteristics and anti-demential and tyrosinase inhibitory activities of these previously unrecorded yeasts were investigated. Almost all of them were oval-shaped and had ascospores except for Dothichiza pithyophila HJ22-4, Diutina siamensis JR37-5, and Canadida gelsemii DC 35-1. Furthermore, they were all sugar-tolerant and able to grow in 20% glucose-containing YPD broth, except for Cyberlindnera culbertsonii HJ31-1. Diutina siamensis JR37-5 had the highest tyrosinase inhibitory activity (30.9%).