• 동아시아식생활학회지
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• 제7권4호
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• pp.538-544
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• 1997

과잉생산 및 저온저장 중에 발생하는 다량의 불량감을 효율적으로 활용하기 위하여 부패된 감에서 알코올발효력이 우수한 균주를 선별하였다. 분리된 균주의 형태학적, 배양학적 특성을 조사한 결과 YJK 20, DJ 97은 각각 Saccahromyces cerevisiae, Saccahromyces kluveri로 동정할 수 있었다. 산업적으로 이용되고 있는 알코올 발효균주와 YPD 변형배지 및 감추출물 배지를 사용하여 각각의 알코올발효력을 비교한 결과 분리주는 산업적으로 이용되고 있는 균주들에 비하여 YPD변형 배지뿐만 아니라, 감추출물 배지에서도 알코올생성력이 우수하였다. 따라서 감을 이용한 알코올발효력이 우수한 균주로 선별할 수 있었다.

• 한국미생물·생명공학회지
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• 제28권6호
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• pp.309-315
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• 2000

To isolate yeast strains producing high concentration of ethanol, 125 strains were subjected to screening. Initially 14 strains able to grow in a medium containing 15%(v/v) ethanol, 7 strains capable of growing in a medium containing 50%(v/v) glucose, 23 strains having relatively fast fermentation rates, 13 strains able to grow at $42^{\circ}C$ were selected. After secondary screening, 11 strains having relatively high ini-tial fermentation rate and producing high concentration of ethanol were selected. After tertiary screening 5 strains producing high concentration of ethanol were selected. These 5 strains were again for their ethanol produc-tion, residual sugar, and viability using fermentation medium containing 25% glucose. The strain producing the highest concentration of ethanol was 20-1 strain which produced 10.56%(v/v) ethanol in 4 days, and the highest viable strain was 11-1 which produced 10.35%(v/v) ethanol(13.1%. v/v) with the viability of 30.44% after 5 days of fermentation. Both of the 20-1 and 11-1 strains were identified as Saccharomyces cerevisiae.

• 한국미생물·생명공학회지
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• 제22권1호
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• pp.85-91
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• 1994

The characteristcs of monascus fermentation using a hyperpigment-producing mutant, Monascus sp. J101, were analyzed, and the extractive fermentations employing permeabilizing agents and resin were carried out to increase the productivity of red pigment. And the kinetic analysis was also carried out in case of the monascus fermentation using Amberlite XAD-7. The extracellular content of the red pigment produced by Monascus sp. J101 was about 17% of the total, and the production of pigment was regulated by its own product. The cell growth reached a stationary phase at 48 hours ofter inoculation, whereas the pigment production continued up to 100 hours, which showed the pattern of a mixed growth-associated type. During the fermentation, various permeabilizing agents were added to the culture medium and their effects on pigment production were examined. By adding 0.05% Triton X-100 at 48 hours of cultivation, about an 18% increase in pigment production was accomplished as compared to the control, 12% ethyle acetate and 15% for 0.05% deoxycholate, respectively. When a nonionic adsorbent, Amberlite XAD-7 was added to the culture medium at a concentration of 12.0% at 48 hours of cultivation, the pigment production was enhanced by about 48.9% as compared to the control.

• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1574-1582
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• 2020

Flavonoids have diverse biological functions in human health. All flavonoids contain a common 2-phenyl chromone structure (C6-C3-C6) as a scaffold. Hence, in using such a scaffold, plenty of high-value-added flavonoids can be synthesized by chemical or biological catalyzation approaches. (2S)-Naringenin is one of the most commonly used flavonoid scaffolds. However, biosynthesizing (2S)-naringenin has been restricted not only by low production but also by the expensive precursors and inducers that are used. Herein, we established an induction-free system to de novo biosynthesize (2S)-naringenin in Escherichia coli. The tyrosine synthesis pathway was enhanced by overexpressing feedback inhibition-resistant genes (aroG^fbr and tyrA^fbr) and knocking out a repressor gene (tyrR). After optimizing the fermentation medium and conditions, we found that glycerol, glucose, fatty acids, potassium acetate, temperature, and initial pH are important for producing (2S)-naringenin. Using the optimum fermentation medium and conditions, our best strain, Nar-17LM1, could produce 588 mg/l (2S)-naringenin from glucose in a 5-L bioreactor, the highest titer reported to date in E. coli.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.1028-1034
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• 2021

The effect of medium composition on enzyme and β-glucan production by Aspergillus oryzae KCCM 12698 was investigated. Brown rice, rice bran, nitrogen, and ascorbic acid are key components of the synthetic medium used in liquid-state fermentation. To determine the optimal concentrations of these components for enzyme and β-glucan production, we conducted one factor at a time experiments, which showed that the optimal concentrations were 30 g/l brown rice, 30 g/l rice bran, 10 g/l soytone, and 3 g/l ascorbic acid. Pretreatment of brown rice for 60 min prior to inoculation enhanced fungal biomass, while increasing the production of enzymes and β-glucan using solid-state fermentation. Maximum fungal biomass of 0.76 mg/g, amylase (26,551.03 U/g), protease (1,340.50 U/g), and β-glucan at 9.34% (w/w) were obtained during fermentation. Therefore, solid-state fermentation of brown rice is a process that could enhance yield and overall production of enzymes and β-glucan for use in various applications.

• Asian-Australasian Journal of Animal Sciences
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• 제13권4호
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• pp.451-456
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• 2000

Fifty mid-lactation Holstein cows were used in a six-week feeding trial to study effects of high-forage, and high-fat diets on blood constituents, rumen fermentation and dry matter digestibility. Cows were divided into 10 replicates, each consisting of five cows. Each cow was assigned to a control (diet 1) or one of the four experimental diets (high-forage (75%), high-fat (7.5%) (diet 2); high-forage. medium-fat (5.0%) (diet 3); medium forage (65%), high-fat (diet 4); medium-forage, medium-fat (diet 5)), or a control diet containing about 50% forage and 2% fat. All diets were isonitrogenous (17.7% crude protein). The forage mixture consisted of 20% alfalfa hay, 40% alfalfa haylage, and 40% corn silage. Supplemental fat included 80% rumen-protected fat and 20% yellow grease. A non-significant difference was observed in concentrations of blood glucose for cows on different experimental and control diets. Plasma nonesterified fatty acids (NEFA) were higher in cows consuming experimental diets than those consuming the control diet. However, differences in NEFA concentrations in the plasma of cows consuming diets with different forage and fat levels were not significant. Rumen pH, concentration of volatile fatty acids (VFA) in rumen contents, and dry matter digestibility of control and experimental diets, and diets with different levels of forage and supplemental fat did not differ significantly.

• KSBB Journal
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• 제14권5호
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• pp.628-632
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• 1999

에리스리톨을 산업적으로 대량생산하기 위해서는 에리스리톨의 생산성을 높이고 부산물인 글리세롤의 생성을 억제하는 배지 및 발효 공정의 최적화가 필요하다. 에리스리톨 생성을 위한 최적 탄소원은 포도당이고 최적 농도는 400 g/L이며 최적 온도는 3$0^{\circ}C$였으며 이 때 산소는 과잉으로 공급해 주어야 함을 알았다. 에리스리톨의 수율과 생산성을 향상시키기고 배지가격을 줄이기 위해 효모 추출물의 사용을 5 g/L에서 3 g/L로 줄이고 urea 2.72g/L$K_2HPO_4$ 1.79 g/L, MgSO$_4$. $7H_2O$ 0.18 g/L를 첨가해 줌으로써 에리스리톨 수율을 31.4%에서 45.2%로 에리스리톨 생산성을 0.747 g/L/h에서 1.071 g/L/h로 향상시켰다. 또한 글리세롤의 생산량도 96.6 g/L에서 45.7 g/L로 줄었다. 이 최적 배지를 바탕으로 5L 발효기에서의 재현성과 pH에 대한 영향을 알아보기 위해 실험을 한 결과 pH를 조절한 경우에 에리스리톨 생산성이 낮아졌다. 5L 발효에서는 다량의 거품이 발생되는 것을 관찰하였다.

• Journal of Dairy Science and Biotechnology
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• 제31권1호
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• pp.51-58
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• 2013

Emerging studies suggest that vegetables or fruit juices deemed to be potential alternative base medium for lactic acid bacteria fermentation. Until now, limited studies have been carried out to evaluate such applications. Thus, the objective of present study is that lactic acid bacteria were evaluated for their viability at low pH, growth during storage at low temperature, and $CO_2$ formation. Furthermore, the effects of grapefruit extract with respect to cell viability, sensory ability, and organic acid production were evaluated for these strains. The probiotic properties of the strains, including acid tolerance, bile tolerance, and adhesion to human intestinal epithelial cells (HT-29 cells), prebiotic characteristics, and safety features were examined. All strains survived in MRS medium broth adjusted to pH 3.8, at $10^{\circ}C$ for 6 days, and did not produce $CO_2$ to check post fermentation. The medium of grapefruit extract fermentation by Lactobacillus plantarum CJIH 203 resulted in maximal viable counts, compared with other strains, and the extract subsequently tasted sour due to the presence of lactic acid. Lactobacillus plantarum CJIH203 was highly resistant to artificial gastric juice and intestinal juice, while Lactococcus lactis SJ09 strongly adhered to HT-29 cells. Tagatose showed the greatest ability to enhance the growth of L. plantarum SJ21, relative to the other strains. All strains were verified by safety tests such as hemolysis, gelatin hydration, and urea degradation. Therefore, these strains could be promising candidates for use in reducing excessive post-fermentation and functional products.

• 미생물학회지
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• 제42권3호
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• pp.172-176
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• 2006

Streptomyces toxytricini로부터 lipstatin생산을 최적화하기 위해, 배지 성분이 lipstatin생산에 미치는 영향을 조사하였다. 이를 위해 tryptic soy broth (TSB) 배지를 기본 배지로 하여 $28^{\circ}C$, 200 rpm 으로 3일간 배양하여 총 배양액(seed culture) 을 만들고, 여기에 다양한 탄소원, 질소원, 지질 및 지방산등을 함유한 TSB 배지에 2% 접종한 후 60시간 동안 주 발효를 실시한 후, 배지 중의 lipstatin양을 측정하였다. 탄소원 중에서 glucose와 glycerol을 첨가한 배지에서 균체가 가장 잘 성장하였지만, lipstatin생산에는 lactose나 sucrose가 가장 우수한 것으로 나타났다. 한편, 질소원으로는 yeast extract가 균체 성장에 가장 좋았지만, 1.7% casitone과 0.3% soytone으로 구성된 TSB 배지에서 lipstatin생산량이 가장 높게 나타났다. 또한 lipstatin생산을 증가시키기 위해 triolein을 발효 배지에 첨가한 결과, 균체 성장은 증가하였지만, lipstatin의 생산은 현저히 감소하는 경향을 보였다. 한편, lipstatin의 생합성 원료로 추정되는 지방산들을 발효 배지에 0.5% 첨가하여 발효를 실시한 결과, 불포화 지방산인 linoleic acid나 oleic acid를 첨가한 경우 S. toxytricini의 성장이 억제되었으나, 포화 지방산인 stearic acid를 첨가한 경우에는 균체성장 뿐만 아니라 lipstatin 생산량도 증가하였다.

• 한국미생물·생명공학회지
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• 제6권4호
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• pp.161-165
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• 1978

자연계에서 유기산을 생성하는 균주 11 군주를 분리하여 그 중에 구연산 생성균 1종을 선정하여, 동정한 결과 Aspergillus niger로 나타났다. 분리된 균주로 500ml 삼각 flask에 Sakaguchi 배지 100ml를 넣고 3$0^{\circ}C$에서 발효한 결과 구연산이 17g/ι가 생성되었다. 또한 Sakagnchi 배지를 개량한 결과 즉 배지적응, peptone첨가, 통기 효과, methanol첨가 및 포도당 첨가 결과 구연산이 35g/ι가 생성되었다