• KSBB Journal
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• v.15 no.1
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• pp.76-79
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• 2000

Complex, ill-defined mixtures of natural origin are often used as nutrients in the production of biological products through microbial fermentation. Product yields are affected by variation in these natural products. Yeast extract is a typical example of these natural products. Since it is a mixture of amino acids, peptides and nucleic acids, its composition is not well characterized. In this study, we investigated the properties of thiamine hydrochloride, riboflavin and pyridoxine hydrochlride in yeast extract by using a gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography. Yeast extract solution was fractionated by gel filtration chromatography and ion exchange chromatography, and then, each fraction was analyzed by using a high performance liquid chromatography.

• Journal of Animal Environmental Science
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• v.7 no.1
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• pp.21-28
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• 2001

Optimal conditions for utilizing the slaughtered porcine blood and liver for yeast culture and the effects of the yeast cultures on the growth of broiler chicks were investigated. The quantity of yeast cultured for 24hours in the BSG medium containing blood extracts containing 5% glucose and in the LSG medium containing liver extracts containing 5% glucose were higher by 4% and 10%, respectively, than that in the YEPD medium containing 1% yeast extracts, 2% bacto pepton and 2% glucose. Optimal concentrations of ammonium sulfate supplementation to the BSG medium to increase the quantity of yeast cultured for 24 and 48 hours were 100 mM(1.3%) and 50 mM(0.65%), respectively. The optimal pH for yeast culture in BSG medium ranged from 6 to 7. One percent supplementation of either ammonium sulfate or taurine to LSG medium increased the quantity of yeast by 18% and 9%, respectively, compared to no supplementation. The body weight of chicks fed with 2% and 4% yeast culture supplementations cultivated increased at the 4th week by 10%, with relative to no supplementation. The results from this study suggest that the slaughtered porcine blood and liver can be utilized for yeast culture which is used in animal diets.

• The Korean Journal of Food And Nutrition
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• v.14 no.3
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• pp.217-221
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• 2001

Lactobacillus spp. PAP1 과 Lactobacillus spp. MG-G2를 혼합구조로 사용하여 밤 발효제품을 제조하기 위한 제반 조건을 조사하였다. 밤 발효액은 phytone peptone, yeast exract, glucose를 각각 0.4, 0.2. 0.5%이상으로 첨가할 때 산도와 생균수가 가장 컸다. 첨가물 중 phytone peptone은 대두박이나 순물로 대체해도 같은 효과가 관찰되었다. 버섯추출물의 첨가는 산도와 생육을 약간 촉진하였으나 안정제는 약간의 감소를 가져왔다. 기본 발효액은 관능성적이 나빴으나 산도를 0.54%로 낮추고, 당을 10%로 보강하고, so-dium alginate를 0.2% 첨가하였을 때, 산미, 감미, 음용감이 크게 개선되었다

• Korean journal of applied entomology
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• v.12 no.1
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• pp.23-27
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• 1973

In an effort to find effective inoculation method of Fusarium nivale, this experiment was conducted. The results obtained are summarized as follows: (1) Distilled water-spore suspension of this fungus was inoculated on rice seedling and the result showed that negligible disease symptoms were observed when the inoculated plants were placed in a moist chamber for one day, whereas considerable symptoms were indicated when kept for two days. (2) After giving physical wounds by wind or wooden stick to the rice seedling, distilled water-spore suspenion was sprayed on them and considerable diseased spots were formed. (3) Sufficient disease occurrence was due to the addition of $1\%$ rice leaf extract, glucose, polypeptone, and yeast extract solution to the spore suspension. (4) In distilled water, spore germination was poor, while in nutrient added solution good germination rate as well as anastomosis was found. (5) A new rice variety Tong-il turned out to be more susceptible to Fusarium nivale than Pung-kwang.