• Korean Journal of Microbiology
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• v.38 no.4
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• pp.209-209
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• 2002

Mycobacterium sp. strain JCl DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in mast methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed, in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JCl. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly Of indirectly in Mycobacterium sp. JCl.

• Food Science and Preservation
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• v.12 no.1
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• pp.90-94
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• 2005

To poodnce a value added of mulberry, this study was optimized the condition for manufacture of wine using mulberry. On fermentation of mulberry wine, the best yeasts were Saccharomyces cerevisiae JBS 30 and JBS 33, and optimum composition of medium was crushed mulberry juice of $50\%$, sugar of $24\;^{\circ}brix,\;Na_2S_2O_5\;of\;0.02\%$. The content of alcohol after fermentation of 10 days at $25^{\circ}C$ was $11.2\%$. Sensory evaluation showed that color, taste and odor of mulberry wine were acceptable, and Saccharomyces cerevisiae JBS 30 was not difference compared to JBS 33.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.187-191
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• 1970

This experiment was carried out to isolate osmophilic yeasts for higher concentration of NaCl than 20 per cent may affect greatly the fermentation of soy sauce. 6 strains of yeasts were selected from the soy sauce mashes at the fermentating periods and identified observing their morphological characteristics. Their salt-resistance and effects upon the flavor of soy sauce were examined. The results obtained were as follows: (1) The strain $T_3,T_5,$ and $T_{11},\;T_8,\;T_9,\;and\; T_{10},$ selected were identified Saccharomyces cerevisiae group II, Debaryomyces nicotianae, Saccharomyces chevalieri, Saccharomyces rouxii and Saccharomyces rosei, respectively. (2) They were more salt-resistant on the liquid media than on the solid media in the case of cultures on the media containing more than 26 per cent of NaCl. (3) They were grown on the media containing 5-23 per cent of NaCl better than containing none of NaCl. (4) The strain $T_3,\;T_8,\;T_9,\;and\; T_{10}$ were grown on the media containing up to 28 per cent of NaCl, and $T_5\;and\;T_{11}$ up to 32 per cent of NaCl is the case of liquid cultures. (5) Among them, the strain $T_9$ showed the best alcohol fermentation ability and the best fermentative flavor, and $T_5\;and\;T_{11}$ formed moldy smell and pellicle.

• Korean Journal of Food Science and Technology
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• v.7 no.2
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• pp.61-68
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• 1975

This study was conducted (1) to isolate the film-forming yeast from the commercially available soy sauce, (2) to identify the state of soy sauce fermentation by the use of yeasts, (3) to confirm characteristics of yeasts. The result were as follows. 1. These yeast strains in the soy sauce fermentation test showed full fermentation of whole sugar content, reduction of the pure extract and relative reduction in total nitrogen. Soy sauce color was somehow faded to lower the stability of soy sauce. 2. In anti-fungal activity test butylparaben at a higher level 60 ppm., sodium propionate 2,400 ppm, sodium benzoate 800 ppm., menadion 165 ppm, showed their anti-fungal effect, while alcohol did not show the effect in the 3% additive group. 3. The optimum sodium chloride concentration for these strains in the 2% G.Y.P. medium was 5% and optimum temperature was $30^{\circ}C$. The extinction temperature was $62^{\circ}C$ for strain No-1 and No-3, and was $65^{\circ}C$ for No-2 and No-4. 4. The film-forming soy sauce turned out in the gas chromatogram to possess much flavor of low boiling point as compared with the standard. These flavors were considered due to flavor spoilage of the soy sauce. 5. These isolated yeasts were identified Saccharomyces rouxii (film-forming yeast) in the Lodder's taxanomic study.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.296-301
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• 2009

In order to investigate the effect of different yeasts (La Parisienne (LP), Y18-2, Y54-3, Y90-2, Y90-9 and Y272-7) from nuruks on the quality of Glutinous rice wines, physicochemical properties and volatile flavor components were evaluated. Glutinous rice wines prepared with different yeasts were analyzed for ethanol, pH, total acid, amino acid, soluble solid, coloring degree, UV absorbance, reducing sugar, organic acid, free sugar and volatile compounds. After fermentation for 17 days, the ethanol contents ranged from 13.40 to 14.50%, while the total acid levels were from 0.33 to 0.44%. The amino acid contents in six samples ranged from 0.13 to 0.18%, while soluble solid contents ranged from 12.1 to $14.7^{\circ}Bx$. The glutinous rice wine prepared with LP showed the highest level of coloring degree, soluble solid and reducing sugar among six samples. Organic acid contents of the glutinous rice wine prepared with LP had the highest levels of lactic acid and acetic acid, while the glutinous rice wine prepared with Y90-9 had the highest level of succinic acid. In all glutinous rice wines tested, the most abundant free sugars were glucose followed by maltose. Volatile flavor components in the glutinous rice wines were identified by using GC-MSD. Nineteen esters, ten alcohols, eight acids, one aldehyde and one miscellaneous compound were identified in the glutinous rice wines. Using relative peak area, it was found that other than ethyl alcohol, hexadecanoic acid ethyl ester was the major component, predominantly found in the range of 2.73-10.41%. Phenylethyl alcohol, isoamyl alcohol, ethyl oleate, ethyl linoleate and tetradecanoic acid ethyl ester were some of the major volatile components present through the fermentation, respectively. Overall, it was shown that different yeast strains from nuruks greatly affected chemical and volatile characteristics of the glutinous rice wines.

• Journal of Microbiology
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• v.41 no.3
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• pp.219-223
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• 2003

The toxicity of chlorothalonil on the growth of yeasts was investigated using several yeast strains. An alcohol tolerant yeast, Saccharomyces cerevisiae F38-1, was the most chlorothalonil-tolerant. The glutathione content and the glutathione S-transferase activity were related to the chlorothalonil-tolerant phenotype. Several thiol compounds affect the dissipation of chlorothalonil. However, there was no significant difference on the effects of chlorothalonil dissipation among the thiol compounds tested. The growth of yeast cells was arrested by chlorothalonil. It took about 13 h to dissipate 1 mg/l of chlorothalonil, and the growth was restored as the chlorothalonil content decreased. The glutathione content and glutathione S-transferase are suggested to be among the most important factors of yeast resistance to chlorothalonil.

• Journal of Microbiology and Biotechnology
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• v.1 no.1
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• pp.6-11
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• 1991

This study deals with investigation of the ethanol tolerance of yeast strains with respect to fatty acid composition and intracelluar ethanol concentration during alcohol fermentation. The cell viabilities and fermentation abilities of Saccharomyces cerevisiae and Kluyveromyces fragilis were improved by aeration and addition of unsaturated fatty acids into growth medium. Aeration decreases the accumulation of ethanol, while increases unsaturated fatty acid contents inside yeast cells. Thus it was found that oxygen and unsaturated fatty acids play decisive roles in the increase of ethanol tolerance of yeasts.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.316-321
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• 1994

We investigated the possibility of industrial application and economit process of high temperature fermentation by thermotolerant alcohol producing yeasts as previously reported. From the 20% glucose media, the RA-74-2 produced 11.8% (v/v) ethanol at $32^{\circ}C$ (0.5% inoculum) and 10.6% (v/v) ethanol at $40^{\circ}C$ (3% inoculum), respectively. Also, 11.3% (v/v) ethanol was produced for 96 hours in the temperature-gradient fermentation. These results suggest that the RA-74-2 could isuccessfully be applied to save the cooling water and energy in industrial scale without re-investment or modification of established fermentation systems. When potato starch was used as the substrate for the RA-74-2, high temperature fermentation above $40^{\circ}C$ was more appropriate for industrial utilization because organic nitrogen was not necessary to economical fermentation. As the naked barley media just prior to industrial inoculation, taken from the Poongkuk alcohol industry Co., were used, 9.6% (v/v) ethanol was produced at $40^{\circ}C$ for 48 hours in jar-fermentor scale (actually, 9.5-9.8% (v/v) ethanol was produced at 30~$32^{\circ}C$ for 100 hours in industrial scale). The ethanol productivity was increased by the high glucoamylase activity as well as the high metabolic ratio at $40^{\circ}C$ Therefore, if the thermotolerant yeast RA-74-2 would be used in industrial scale, we could obtain a high productivity and saving of the cooling water and energy. Meanwhile, the RA-912 produced 6%(v/v) ethanol in 10% glucose media at $45^{\circ}C$ and showed the less ethanol-tolerance compared with industrial strains. As the produced alcohol was recovered by the vacuum evaporator at $45^{\circ}C$ in 15% glucose media, the final fermentation ratio was enhanced (76% of theoretical yields). This suggest that a hyperproductive process could be achieved by a continuous input of the substrate and continuous recovery of the product under vacuum in high cell-density culture.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.386-390
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• 1997

The characteristics of alcohol dehydrogenase (ADH, EC 1.1.1.1, alcohol:NAD oxidoreductase) of thermotolerant alcohol-producing yeasts, Saccharomyces cerevisiae RA-74-2 and Kluyveromyces marxianus RA-912, were compared with that of mesophilic S. cerevisiae D, an industrial strain. Under anaerobic culture condition, both S. cerevisiae RA-74-2 and D had similar level of ADH activity at 30$\circ$C, and the activity of S. cerevisiae RA-74-2 at 37$\circ$C was the same level at 30$\circ$C. However, the level of ADH activity of S. cerevisiae D at 37$\circ$C decreased about 70% of that at 30$\circ$C. The level of enzyme activity of K. marxianus RA-912, which showed lower alcohol productivity than S. cerevisiae RA-74-2 and D, was about 43% of those strains at 30$\circ$C, and decreased somewhat at 37$\circ$C. The results showed a good correlation between the alcohol productivities and the level of ADH activities of these strains grown at 30$\circ$C and 37$\circ$C. And the higher heat stability of ADH of S. cerevisiae RA-74-2 than that of S. cerevisiae D seemed to reflect the ability of high temperature fermentation. Despite of its fermentation ability even at 45$\circ$C, however, the ADH of K. marxianus RA-912 showed lower heat stability than that of S. cerevisiae D. Both S. cerevisiae RA-74-2 and D showed similar patterns of two bands of ADH isozyme, and the low band of S. cerevisiae RA-74-2 moved slightly faster than that of S. cerevisiae D. The staining intensity of the bands of S. cerevisiae D at 37$\circ$C was weaker than those at 30$\circ$C. However, S. cerevisiae RA-74-2 showed no differences in total intensity of the bands of 30$\circ$C and 37$\circ$C. As the patterns of cellular proteins and ADH isozyme of K. marxianus RA-912 were different from S. cerevisiae RA-74-2 and D, K. marxianus might have its own characteristic ADH system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.1077-1082
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• 2007

In this study, killer yeasts were isolated from traditional Nuruk to improve storage and suppress contaminant in food industry. Among killer yeasts, yeast K15 showed strong killer toxin activity and inhibited growth of Salmonella Typhimurium and Vibrio parahaemolyticus. Killer yeast K15 was identified with Pichia anomala by the Microlog TM 4.0 identification system and homology of the ITS sequence. Killer toxin generated from P. anomala K15 was inactivated by pronase E and suggested to be a protein. Therefore killer toxin of P. anomala K15 was thought to be safe in human such as bacteriocin. P. anomala K15 was sufficient for growth in 50% glucose and could be used to prevent contaminant in initial stages of alcohol beverage fermentation.