• 한국미생물·생명공학회지
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• 제19권2호
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• pp.116-121
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• 1991

A bacterial strain KN, which highly produced a protease, was isolated from several soil samples and identified to to belong to the genus Bacillus. We selected mutant strain Bacillus sp. KN103N, which was hyperproducer of protease and was resistant to D-cyclowerine, from the strain KN by several steps of mutagenesis. Neutral protease productivity of mutant strain KN103N was about 55 times as much as that of the original strain KN. The optimum pH and temperature for the enzyme activity were 7.0 and 50$^{\circ}C$, respectively and the enzyme was relatively stable at pH6.0~8.0 and below 40$^{\circ}C$. The enzyme was inactivated by EDTA, but not by DFP. These results indicate that the enzyme from Bacillus sp. KN103N was a neutral (metallo-) protease.

• 한국축산식품학회지
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• 제37권1호
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• pp.147-152
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• 2017

A bioluminescent Lactobacillus plantarum (pLuc2) strain was constructed. The luminescent signal started to increase during the early exponential phase and reached its maximum in the mid-exponential phase in a batch culture of the strain. The signal detection sensitivity of the strain was the highest in PBS (phosphate buffered saline), followed by milk and MRS broth, indicating that the sensitivity was influenced by the matrix effect. The strain was used in millet seed fermentation which has a complex matrix and native lactic acid bacteria (LAB). The luminescent signal was gradually increased until 9 h during fermentation and abolished at 24 h, indicating that the strain could be specifically tracked in the complex matrix and microflora. Therefore, the bioluminescent labeling system can be used for monitoring LAB in food and dairy sciences and industries.

• 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.

• KSBB Journal
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• 제8권1호
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• pp.1-9
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• 1993

The acetone-butanol fermentation by C. acetobutylicum has gained increasing attention for the following reasons. First, the finite supply of petrochemical resources, combined with increasing concern over global environmental effects and the unstable nature of the price of petroleum has renewed interest in the development of fermentation technology that allows utilzation of biomass wastes for the production of alcohol. Second, it serves as excellent model system for understading the regulation and molecular biology of tightly regulated complex primary metabolism, and for applications of metabolic engineering. In this review various aspects of acetone-butanol fermentation by C. acetobutylicm including strain and fermentation characteristics, enzyme regulation, and solvent formation mechanism, and product recovery and summarized.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1729-1738
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• 2019

In sourdough fermentation, lactic acid bacteria perform important roles in the production of volatile and antimicrobial compounds, and exerting health-promoting effects. In this study, we report the probiotic properties and baking characteristics of Lactobacillus plantarum SPC-SNU 72-2 isolated from kimchi. This strain is safe to use in food fermentation as it does not carry genes for biogenic amine production (i.e., hdc, tdc, and ldc) and shows no β-hemolytic activity against red blood cells. The strain is also stable under simulated human gastrointestinal conditions, showing tolerance to gastric acid and bile salt, and adheres well to colonic epithelial cells. Additionally, this strain prevents pathogen growth and activates mouse peritoneal macrophages by inducing cytokines such as tumor necrosis factor-α, interleukin (IL)-6, and IL-12. Furthermore, the strain possesses good baking properties, providing rich aroma during dough fermentation and contributing to the enhancement of bread texture. Taken together, L. plantarum SPC-SNU 72-2 has the properties of a good starter strain based on the observation that it improves bread flavor and texture while also providing probiotic effects comparable with commercial strains.

• 미생물학회지
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• 제9권2호
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• pp.55-60
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• 1971

Among 50 yeasts of red pepper paste isolated and identified in the previous report, 12 strains of yeast which possess osmophilic and non-film characteristics were examined their growth rates and alcohol fermentation ability in red pepper medium. 5 strains of yeast possessing powerful growth rates and excellent alcohol fermentation ability were selected as excellent yeasts in this experiment. And their cultural conditions, salt resistance and red pepper concentration upon the growth were examined in this report. The results obtained were as follows ; 1) Among 12 strains of yeast, Saccharomyces cerevisiae group II(strain $D_1$), Saccharomyces oviformis($D_2$), Saccharomyces steineri($M_3$), Saccharomyces rouxii($D_9$) and Saccharomyces mellis($G_8$) were selected as excellent yeasts. 2) Among 5 strains of yeast selected, the strain $D_1$ and $D_2$showed the best alcohol fermentation ability and the best fermentative flavour. 3) The optimum temperature for growth of the strain $D_1$ and $D_2$ was $25^{\circ}C$$M_3$, $D_9$ and $G_8$ $30^{\circ}C$$D_1$ and $D_2$ was $62^{\circ}C$$M_3$,$D_9$ and $G_8$ ws 60.deg.C with treatment for 10 minutes. 4) The optimum pH for growth of all strains was around 5.0. 5) The strain $D_1$ and $M_3$were grown exceedingly well on the emdia containing 3 percent of NaCl and $D_2$,$D_9$ and $G_8$ on the media containing 6 percent of NaCl. 6) In the case of 5 percent of red pepper liquor added 5 percent of glucose was more nutritional than in the case of 5 percent glucose only. However, the growth rates of yeasts were restrained by the increase of red pepper concentration.

• 한국융합학회논문지
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• 제12권11호
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• pp.403-410
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• 2021

본 논문은 대체식품 및 화장품 원료로 사용되는 미강을 발효를 통해 기능성과 경쟁력을 증가시키는 것을 목표로 하였다. 5종류의 누룩에서 분리한 Saccharomycopsis fibuligera 50종의 균주 중 효소 활성이 우수한 6균주와 표준균주를 이용한 발효미강물의 𝛼-amylase, CMCase, 𝛽-glucosidase, protease 등의 효소 활성을 통해 비교한 결과, A8균이 KCTC 7806 균주에 비하여 13.7%, 21.1%, 50.3%, 10.0%의 우수한 효소 활성을 보였다. 발효의 결과지표로서 ABTS, DPPH 검사를 시행한 결과, A8으로 발효한 미강이 KCTC 7806 균주로 발효한 미강에 비하여 1.12배, 1.28배의 항산화능이 있음을 확인하였다. 본 논문으로, S. fibuligera 표준균주인 KCTC 7806 보다 우수한 S. fibuligera A8 균주를 확인할 수 있었다. 또한, 선행연구과제의 항염활성 및 항독성 결과와 더불어 우수한 효소 활성과 항산화능 결과를 통해 S. fibuligera A8 균주를 통한 미강 발효물이 대체식품 및 화장품 원료로서의 기능성과 가격 경쟁력을 증가시킬 수 있음을 확인하였다.

• 한국미생물·생명공학회지
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• 제40권2호
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• pp.98-103
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• 2012

경기도 일대에서 수집한 메주 시료에서 지질분해 활성을 나타내는 균주 Y124를 분리하여 동정한 결과 Yarrowia lipolytica와 100% 상동성을 보였다. 분리 균주가 생산하는 lipase의 조효소에 대한 일반적인 특성을 조사한 결과, 탄소원으로 olive oil을 단독으로 사용한 YPO 배지에서 8시간 배양하였을 때 lipase 활성이 가장 높게 나타났다. YPD 배지에서는 lipase 활성이 거의 없었으며, olive oil과 glucose를 모두 포함하는 YPDO 배지에서는 lipase 활성이 YPO 배지 보다 낮았다. 그리고 olive oil 농도에 따른 lipase 활성을 측정한 결과, olive oil 무첨가보다 0.7% 첨가하여 8시간 배양했을 때 lipase 활성이134 U/mL으로 가장 높게 나타나 lipase의 생산이 olive oil의 첨가에 의해 유도되는 것으로 생각된다. 생육온도에 따른 lipase 활성 측정한 결과, $30^{\circ}C$에 배양하였을 때 배양 8시간에 가장 높은 활성이 나타났고, $25^{\circ}C$와 $37^{\circ}C$에 배양하였을 때는 배양 12시간에 활성이 가장 높게 나타났으며, Y124균주의 lipase 활성 최적 온도는 $30^{\circ}C$로 나타났다. 그리고 lipase의 기질 친화도를 확인한 결과 Y124균주가 생산하는 lipase의 경우 p-nitrophenyl octanoate ($C_8$)에서 가장 높은 활성이 나타났다.

• 미생물학회지
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• 제30권6호
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• pp.546-552
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• 1992

에탄올 내성 및 고 알콜 생성 균주인 S. cerevisiae BU-1 와 glucoamylase 생성 우수 균주인 S. diastaticus A15 를 시험 균주로 하여 genetic manipulation 에 의하여 haploid 인 S. cerevisiae BUI.alpha.26($alc^r thr^-$) 와 S. diastaticus A15a6($STA^+ hom$) 균주를 분리하였다. 이등 효모 균주의 원형질체 형성을 위하여 0.8 M sorbitol 의 존재하에서 zymolyase $200\mu$g/ml 와 $400\mu$g/ml 을 2 시간 동안 처리시 두 균주 모두 95% 이상 원형질체를 얻었다. PEG 6000 을 90 분간 반응시킬 경우 융합 빈도는 $ 3.25 {\times} 10^{-3}$ 이었다. 원형질체 융합으로 생성된 융합주의 유전적 분석, 에탄올 내성, glucoamylase 생성을 측정한 결과, 이들 융합주의 유전자형은 STA $alc^r$ thr hom. '/STA' $alc^r$ thr hom로 예상되었으며, glucoamylase 활성도는 A15a6 의 경우 2.7 units 이었으나, 융합주 F7, F10 은 각각 4.2 와 8.4 units 로 나타났다. 에탄올 내성 시험을 하여 선별한 결과, 가장 우수한 균주인 융합주 7개 중 F7 과 F10 을 선별하였다. 5% 의 녹말이 포함된 발효배양액에서 $30^{\circ}C$ 5일간 배양시 생성된 에탄올 생성은 융합주 F7 과 F10 은 각각 2.0% 와 1.85 이였다.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1242-1251
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• 2016

The ethanol production of Trichoderma reesei was improved by genome shuffling in our previous work. Using RNA-Seq, the transcriptomes of T. reesei wild-type CICC40360 and recombinant strain HJ48 were compared under fermentation conditions. Based on this analysis, we defined a set of T. reesei genes involved in ethanol production. Further expression analysis identified a series of glycolysis enzymes, which are upregulated in the recombinant strain HJ48 under fermentation conditions. The differentially expressed genes were further validated by qPCR. The present study will be helpful for future studies on ethanol fermentation as well as the roles of the involved genes. This research reveals several major differences in metabolic pathways between recombinant strain HJ48 and wild-type CICC40360, which relates to the higher ethanol production on the former, and their further research could promote the development of techniques for increasing ethanol production.