• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.832-841
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• 1998

In order to economically utilize flour brew with Bifidobacterium bifidum as a bread improver, the effect of flour brew on the rheological properties of dough, growth curve and acid production, and symbiosis with yeast were investigated. Growth of bifidobacteria was not increased more than initial seed volume but was consistent during 24 hours of incubation. pH was decreased and T.T.A was increased up to 12 hours of incubation. Symbiosis between bifidobacteria and yeast was little. Bifidobacteria produced more lactic acid than acetic acid in flour brew and the opposite in skim milk broth. This result was inferred from Lactobacillus sp. inherent in flour. On rheological properties of dough, farinograms of flour showed progressively decreasing baking absorption, mixing time and stability as the amount of flour brew increased. The validation of extensograms showed that R/E ratio linearly increased with increment of flour brew, and nearly doubled in all treatments comparing to that of control, which suggest the reduction of actual fermentation time. On visco/amylograms, malt index increased with addition of flour brew, accordingly showing the decrease in viscosity. Break down and set back value decreased with increment of flour brew, suggesting that staling rate of bread can be delayed.

• KSBB Journal
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• v.15 no.4
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• pp.388-392
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• 2000

An on-line glucose flow injection analysis system was developed and used for the automatic analysis and addition of glucose in the cultivationof a Saccharomyces cerevisiae in a korean paper digestion wastewater in order to increase the cell concentration. The system was composed of a ceramic sampler a sampling valve an injection valve an immobilized glucose oxidase column a debbble a flow cell with platinum electrodes a potentiostat a computer and interface system and tubing pumps. The glucose concentration of the wastewater medium was mainitained at the low concentration of $176{\pm}31 mg/L$ with the on-line FIA system and by adding glucose and $>(NH_4)_2S0_4$ the cell concentration as total cell count can be increased by 3.1times.

• KSBB Journal
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• v.8 no.5
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• pp.446-451
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• 1993

In ethanol fermentation, by-products such as glycerol, acetic acid and lactic acid are produced along with ethanol. The effects of culture conditions on cell growth ethanol production and by-products biosynthesis were investigated in ethanol fermentation using S. cerevisiae. With increasing aeration rate or yeast extract concentration, ethanol and by-products biosynthesis decreased while final cell mass increased. With increasing glucose concentration or decreasing temperature, final cell mass, ethanol and by-products concentrations all increased. The optimal pH for the cell growth, ethanol and by-products productions was found to be pH 4.5. By-products biosynthesis was found, in general, to proceed with the ethanol biosynthesis. The results can be applied for the optimization of ethanol fermentation and for the recovery and purification of ethanol from the culture broth.

• Journal of Life Science
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• v.12 no.4
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• pp.477-482
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• 2002

As a biological model system for the production of an active antibacterial peptide, we have attempted the expression and secretion of insect defensin in Saccharomyces cerevisiae. Nucleotide sequences encoding mature defensin composed of 40 amino acids were fused in frame with promoter and signal sequence of Saccharomyces diastaticus glucoamylase, and mating factor $\alpha$ l[MF $\alpha$1] prosequence. The host strain, S. cerevisiae 2805 was transformed with the resulting plasmid, pSMFll The secretion of functional defensin was confirmed by growth inhibition zone assay using Micrococcus luteus as a test organism. Insect defensin was secreted to the culture supernatant in biologically active form by glucoamylase signal sequence and mating factor $\alpha$1 prosequence. Most of antibacterial activity was detected in the culture supernatant. Defensin was also active against Staphylococcus aureus and Listeria monocytogenes.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.85-90
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• 1992

Rice bran was employed as a main medium component for ethanol fermentation by Saccharomyces species. Among the several strains of .Saccharomyces yeasts. S. cerevisiae IF0 2346 was selected as the hest strain in view of the interest in the production of ethanol and amino acids. It was found that S. cerevisiae IF0 2346 showed $3\times 10^8$cells/d and 4.7% (v/v) ethanol production after 72 hr cultivation. Although total amount of free amino acids was decreased from 1.099 mg/l to 829 mg/l during the fermentation, glutamic acid. histidine, and isoleucine were increased considerably. With the supplement of 5% glucose to the ferrnentation medium, both ethanol and amino acid production were increased up to 134% and 264%, respectively. compared to the control case. Glutamic. acid, leucine, alanine. phenylalanint:, and valine were the major amino acids in the fermentation broth.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.391-395
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• 1985

In order to develope a protoplast fusion system for citric acid and SCP producing Candida lipolytica, the optimal conditions for the formation and regeneration of protoplast were examined and the protoplast fusion was performed. At the optimal conditions of growth phase and Zymolyase treatment, frequencies of protoplast formation were 98%. Approximately 20-30% of protoplasts were regenerated on the regeneration minimal medium containing 3% agar and 30mM $CaCl_2$ with the overlay of the same medium. The fusion frequencies, 4-5${\pm}$10$^{-4}$, were accomplished by the treatment of two nutritionally complementary auxotrophic protoplasts, L-14 ($lys^-$) and T-24 (X$30^-$), with 30% PEG 6000 containing 100mM $CaCl_2$ at $30^{\circ}C$ for 20 minutes.

• Korean Journal of Microbiology
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• v.11 no.3
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• pp.134-151
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• 1973

The physico-chemical and biological factors of coastal sea water were measured bimonthly from 1976 to 1979 for elucidating the relationship between microbial distribution and environmental factors at Masan and Jinhae bay. The experimental results are summarized as followings : 1) The polulation size of bactriz in sea water were increasing as the water temperature increased, and that was higher at station 2 and 3 than at station 1. The number of fungi showed the highest value on July on bottom. The population size of yeast showed no seasonal variation and also showed a relation with the geographic distance. 2) The correlationship between microbial distribution and environmental factors showed little coefficiency in surface water. And the other hand, at bottom water, between general bacteria and water temperature and dissolved oxygen, and between yeast and salinity, there were relatively high coefficiecy.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.145-149
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• 1985

Studies were conducted on the conditions for yeast protoplast regeneration in Hansenula anomala var.anomala FRI YO-32 and Saccharomyces cerevisiae. Protoplasts lysed when suspended in hypotonic solutions of KCI, and the least degree of osmolysis was shown in the hypertonic solution containing 1.4M KCI for the strain FRI YO-32 or 0.8M KCI for S. cerevisiae. It was considered that the concentration of agrar and KCI, and protoplast plating method were the main factors influencing regeneration of yeast protoplasts. Yeast protoplasts were regenerated very favorably when embedded in the complete protoplast regeneration media containing 3％ agar as well as 0.4M KCI for the strain FRI YO-32 or 1.0M KCI for S. cerevisiae. It was shown from the relationship between protoplast formation and regeneration that the higher extent of protoplast formation, the lower extent of protoplast regeneration.

• 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.201.2-202
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• 2003

생체조직에 있어서 환원형 Glutathione(${\gamma}$-L-glutamyl-cysteinyl-glycine, GSH)은 항산화 작용, 간기능 회복 및 해독작용등의 생체 내에서 중요한 생리활성기능을 가지고 있다. 본 연구에서는 glutathione을 다량으로 함유하는 효모균주를 전통 발효주로부터 분리하여 최적 생산을 검토하였다. 분리된 균주는 형태학적, 생리학적 및 생화학적 특성을 검토한 결과 Saccharomyces cerevisiae로 동정되어 FF-8로 명명하였다. Glutathione 생산을 위한 Saccharomyces cerevisiae FF-8의 최적 생산조건은 YM(glucose 1.0%, acid peptone 0.5%, yeast extract 0.3%, malt extract 0.3%) 배지를 기본으로 하여 72시간 동안 진탕배양하면서 검토하였다. Glutathione 생산을 위한 최적 온도, 교반속도 및 pH는 각각 3$0^{\circ}C$, 100 rpm, 그리고 pH 6.0으로 나타났다. Glutathione 최대 생산배지조건은 탄소원으로 3%의 glucose, 질소원으로 3%의 yeast extract, 무기질원으로 0.06%의 KH$_2$PO$_4$및 전구체로 0.06%의 L-Cysteine으로 하였을 때 최대 생산량을 나타내었고, 최적 배지상에서 204$\mu\textrm{g}$/$m\ell$을 생산하였다.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.505-509
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• 1988

Ethanol productivity of a xylose fermenting yeast (Candida sp. X-6-4l) isolated from soil was investigated in laboratory scale using Erlenmeyer flask and mini-jar tormentor. The optimal conditions of xylose fermentation in flask experiment were pH 4, asparagine as nitrogen source, xylose 20g/$\ell$, and in these condition, ethanol yield was about 80% to theoretical yield. Using mini-jar fermentor containing 5% total sugar with 2.5% xylose and 2.5% glucose, we obtained 2.3%(v/ v) ethanol and the corresponding efficiency was 72.3% of total sugar. In this case, the consumming speed of sugar under aerobic condition was faster than that of anaerobic condition, and glucose was used previously to xylose. The optimum concentration of xylose for ethanol fermentation in mini-jar fer-mentor scale was 5%, and the efficiency was 69% of total sugar(Alc.2.2% v/v).