• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.173-179
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• 1978

1) To study the productivity of single cell protein from the n-paraffin utilizing yeast, 235 yeast strains were isolatea from 90 samples 2) Optimum cell growth temperature of three strains selected was 40~45$^{\circ}C$ and these were identified as Candida tropicalis, Candida krusei and Torulopsis molischiana. 3) A-28 strain easily assimilated tetradecane, hexadecane and octadecane, but B-8 strain and C-15 strain assimilated more hexadecane than other n-paraffins. 4) Out of the selected three strains, the mass doubling time, specific growth rate and cell yield were 3.4~4.0 hours, 0.170~0.215, 86~98%, respectively. 5) Crude protein, fat, fiber, ash and nitrogen free extract of the selected three strains were found to be 48.2~61.2% 3.7~8.0%, 3.5~4.2%, 5.6~6.7%, 23.5~31.8%, respectively, and thiamine and riboflavin contents of dried yeast cell were 0.78~0.93 mg% and 6.03~7.3 mg%, respectively. 6) Yeast protein contained evenly most of amino acid, but the sulfur-containing amino acids were particularly low.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.95-100
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• 1982

Torulopsis candida FRI YA-15, a selected yeast, was cultivated in alcohol distiller's waste-filtrate of dried sweet potato for microbial protein production and BOD reduction. The General composition of waste-filterate was BOD$_{5}$ 15700 ppm, COD 36800 ppm, reducing sugar 3300 ppm, total nitrogen 910 ppm, total solids 51800 ppm and ash 390 ppm. The pH of waste was 3.85. The yield to the medium of T. candida cultivated in shake-flask at $25^{\circ}C$ for 48 hrs was 3.38g/$\ell$ and effectiveness in reducing BOD$_{5}$ and COD of waste was 38.9% and 31.8%, respectively. In batch cultivation using 3 $\ell$-jar fermenter, maximum yield to the medium reached 3.2g/$\ell$after 28 hrs cultivation under the condition of temperature 35$^{\circ}C$, initial pH 4.0, aeration rate 2vvm, agitation speed 100rpm. Dry yeast was composed of crude protein 47.98% and ash 5.23%.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.361-363
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• 1988

The prevalence of yeasts in mammary glands of dairy cows and teat cups of milking machines was studied in Chinju area. The rate of subclinical yeast infection in 330 quarters was 3.6%. Of 12 isolates from the milk, 4 Candida pseudotropicalis, 3 C tropicalis, 2 C krusei, 2 C albicans and 1 Rhodotorula spp were identified. The 91.7% of the isolates belonged to the genus Candida and C pseudotropicalis was the predominant species. From 20.5% of 200 teat cups tested, 51 strains of yeasts were isolated. These were 13 C pseudotropicalis, 9 C guilliermondii, 7 C tropicalis, 5 C krusei, 5 C parapsilosis, 3 C albicans, 2 Torulopsis glabrata, 2 Geotrichum candidum and 5 unidentified yeasts. C pseudotropicalis was most frequently encountcred.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.885-891
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• 1996

Various problems in fermented fish products have been a major obstacle to manufacture the product in large scale, which is mainly concerned with the food safety. In this review, salt-fermented anchovy was selected to elucidate the characteristics of microorganisms involved in fermentation; thereby, it is suggested for research areas to achieve the quality improvement of tile product. Different microorganisms were involved in fermentation of anchovy. Dominant species were reported to be Bacillus sp., Pseudomonas sp., and Micrococcus sp., other microorganisms were Vibro sp., Clostridim sp., Serratia sp., Achromobacter sp., Streptococcus sp., Breuibacterium sp., Halobacterium sp., Flavobacterium sp., Corynebacterium sp., Acinetobacter sp., Sarcina sp., Staphylococcus sp., Torulopsis sp., and Saccharomyces sp. To standardize the quality of fermented fish products, screening and isolation of promising microorganisms should be carried out to develop different types of products; at the same time, proper sanitation control should be employed to keep the commercial value of the product by prolonging the shelf life.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.26-30
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• 1990

Candida dattila K109 and K112 isolated from grapes in Korea showed killer activity toward Saccharomyces cereuisiae 5 x 47, S. cereuisiae 1368, Hamenula, Torulopsis, Kluyueromyces, Debaryomyces, and Brettanomyces, and showed the most effective killer activity at 22-26$^{\circ}C$ and at pH 3.9-4.1. The killer actvity of both toxins were remarkably decreased at higher temperature than $25^{\circ}C$ and higher pH than pH 4.0. And the toxins were suggested to be glycoproteins inactivated by pronase E and pepsin. The killer activity was not cured by incubation at elevated temperature of 30-37"C, but cured by treatment with 0.0105-0.3 ppm cycloheximie.imie.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.313-323
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• 1980

The objective of this experiment was to improve the quality and shortening the aging time of Kochujang by adding mixed starter cultures of yeast strains. Kochujangs were mashed during the summer season with mixed starter cultures of Saccharomyces rouxii, Torulopsis versatilis and Torulopsis etchellsii. Enzyme activities and chemical composition of the Kochujang were determined during the period of aging and their organoleptic values were tested. The maximum activities of liquefying amylase and saccharogenic amylase in the Kochujang were obtained during 20 to 60 days and 20 to 30 days after mashing respectively. The acidic protease activity was reached maximum during 20 to 40 days. All enzyme activities were decreased markedly during the final stage of aging period. Among mixed starter cultures tested, mixed culture of T. versatilis and T. etchellsii shows the highest liquefying and saccharogenic amylase activities. Ethyl alcohol contents in 10 days after mashing were highest in the Kochujang with S. rouxii and T. versatilis, followed in order of S. rouxii and T. etchellsii mixture, T. versatilis and T. etchellsii mixture and control without addition of yeast. But the contents in all sample became similar after 20 days with the level of 2.3 to 2.8% and then decreased gradually. The level of reducing sugar contents was markedly increased during the first 10 days, especially in the batches of T. versatilis and T. etchellsii mixture and control. However, the concentration became similar in all samples after 40 days. The contents of amino nitrogen were increased markedly during the first 10 days then slowly up to 90 days. The rate was high in the Kochujang with T. versatilis and T. etchellsii when compared with others. The organoleptic values of all Kochujang made with addition of yeast starter cultures were superior to control, especially in flavor, taste and color. The Kochujang with T. versatilis and T. etchellsii marked the highest value. The data obtained from this experiment suggests that the quality of Kochujang could be improved by using starter culture of suitable yeast strains according to product characteristics and aging time.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.65-90
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• 1979

This study was conducted to establish the brewing method which would be useful for the production of Kochuzang. Kojis, which were made from various materials and microorganisms under a covered condition, were investigated and compared. Yeasts (Saccharomyces rouxii and Torulopsis versatilis) were added to Kochuzang, and the enzyme activity, microflora, chemical composition, nitrogen content, alcohol content and free sugars of Kochuzang were investigated and analysed. The results obtained are as follows: 1. Koji making (1) Glutinous rice-soybean group was superior to glutinous rice group in the saccharogenic and liquefying amylase activities of three day-Koji. (2) Protease activity (acid, neutral and alkaline) of glutinous rice-soybean Koji, which was inoculated with Aspergillus oryzae A, was increased till the 5th day, while other groups showed maximum activity after the 3rd day. (3) The maximum cellulose activity of Aspergillus oryzae B-Koji and A-Koji was observed after the 2nd day and the 3rd day, respectively. High cellulose activity of Aspergillus oryzae B-Koji and A-Koji was respectively shown in glutinous rice group and glutinous rice-soybean group at maximum. (4) Compared with glutinous rice Koji, glutinous rice-soybean Koji gave larger number of yeast and aerobic bacteria. 2. Kochuzang Fermentation (1) Each Kochuzang group shoved different liquefying and saccharogenic amylase activities. The highest activities were generally shown in 10 to 40 days after mashing and remarkably reduced in the last stage of aging. (2) Protease activities of each group were strong in order of acid, neutral and alkaline protease. Especially acid protease showed highest activity at the 40th to 50th day Kochuzang. (3) Each group showed maximum cellulase activity in the 40th and 50th day-Kochuzang and then decreased. (4) Osmophilic yeast of yeast-added Kochuzang after one-month aging was distinctively outnumbered compared with non-yeast-added Kochuzang, but two groups were similar after two months. (5) Yeast-added group and non-added group gave almost the same number of halophilic lactic acid bacteria in Kochuzang, but the non-added group gave slightly larger number of aerobic bacteria than the yeast-added group. (6) Amino nitrogen contents in all test group were increased rapidly till the 60th day of Kochuzang aged. After that the contents were increased slowly. (7) Ethyl alcohol contents of 20day-fermented Kochuzang were high in order of Saccharomyces rouxii-added group, Torulopsis versatilis-added group, Saccharomyces rouxii and Torulopsis versatilis mixed group and non-yeast-added group. But all test group showed about 2% in ethyl alcohol content after 40days of aging. (8) Alcohol content in the 7 month-aged Kochuzang of all test groups was high in order of ethyl alcohol, n-butyl alcohol, n-propyl alcohol and iso-propyl alcohol. Torulopsis versatilis-added group had the highest value of ethyl alcohol, n-propyl alcohol and n-butyl alcohol. (9) Reducing sugar in Kochuzang was increased after 20 days of aging compared with the 10days-ferment. The reducing sugar content in Saccharomyces rouxii-added group was distinctively small compared with that of other groups, decreasing after 30days of aging. (10) Rhamnose, fructose, glucose and maltose were isolated from the 10 day fermented Kochuzang. Raffinose was also found after 300 days-aged group, and fructose content was high in the 300days-aged Kochuzang. However, glucose content was smaller than that of 10days-fermented Kochuzang. (11) For the organoleptic tests of Kochuzang, taste, flavour and color of yeast-added group were superior to the non yeast-added group. Especially the complex yeast group among the yeast added groups were the best of all. Yeast-added group after 300 days of aging took higher paint in flavour test than that of non-added group. Therefore, brewing method like complex yeast added group seems to be advantageous for short time brewing Kochuzang.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.512-519
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• 1997

RNA accumulating strain of Torulopsis versatilis MT-1 was cultured in molasses medium for higher contents of RNA in cell. Yeast cells were harvested at logarithmic phase on synchronous culture. Yield of cells on dry base to input sugar was 59.5%. Crude protein content was 55.1% in cell. RNA content was 13.9%. Some problems found in the process for the preparation of yeast extracts were improved by the addition of culture broth of Streptomyces faecalis MSF which secrete RNase (5' nuclease and 5' adenylic acid deaminase). When the culture broth of S. faecalis MSF was added in autolysis process 46% of RNA in cell was converted to I and G(5' inosinic acid and 5' guanylic acid) in extract. By addition of 3-7% culture broth of S.faecalis MSF in autolysis or enzymolysis process at the start or early stage, RNA in extract was converted easily to I and G and protein in cells was easily extracted and hydrolyzed to amino acid. Taste of those yeast extracts was delicious. The yeasty smell in yeast extracts was removed. And cell debris was easily removed from extract.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.445-451
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• 1996

The strain YCH-37, which produces yeast cell wall lytlc enzyme, was isolated from soil. From the microscopic observation, morphological and cultural characteristics, this strain was identified to fungus, Dicyma sp. So, we named this strain as Dicyma sp. YCH-37. The lytic enzyme effectively lysed Salmonella typhimurium among intact living bacteria and Torulopsis, Hansenula, Zygosaccharomyces among intact living yeast, as well as autoclaved yeast strains. The yeast cell wall lytic enzyme was succesively purified to 204 folds with 13% yields through yeast glucan affinity adsorption and DEAE-cellulose column chromatography. The enzyme was identified to monomeric protein with molecular weight of 25,000 daltons from the results of SDS-PAGE and gel filtration. The optimum pH and temperature for the yeast lytic activity were 8.0 and 50$\circ$C, respectively. The enzyme was stable up to 40$\circ$C, and between pH 4.0-pH 10.0.

• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.43-52
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• 1981

A series of thermal destruction studies of the most heat resistant yeast strain No. 15 among 61 isolates were conducted in order to establish the optimum pasteurization condition of peach solid pack. The results obtained are summarized as follows: 1. A survival curve of the selected yeast strain No. 15 at $58^{\circ}C$ consisted of heat labile and heat stable fraction, showing broken curve. 2. The actively growing cell showed less recovery rate than 10 day rested cell after agitation-growing for 90 hr. For heating menstrua, peptone solution gave higher recovery rate than peach juice. For recovery medium, YM agar gave higher recovery rate than peach juice agar. The selected yeast was more resistant to heat at pH 4.0 than at pH 3.5 in both heating menstrua and recovery medium. 3. Z value of TDT curve of the selected yeast (heating : at pH 3.5 in peach juice. recovery: at pH 3.5 in peach juice agar) was $4.8^{\circ}C$. 4. The selected yeast No. 15 was identified as Torulopsis candida. 5. In the inoculated pack test of 4 oz can, it was concluded that the optimum P.U. 70/5 was 168 (center temp; $78.5^{\circ}C$, initial temp; $18^{\circ}C$, processing time; 18 min, initial yeast count; $1.0{\times}10^7$ per can).