• Journal of Life Science
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• v.31 no.8
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• pp.761-770
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• 2021

In this study, the optimal medium composition for enhancing protease production was established by the Bacillus strain isolated from Makgeolli, a traditional fermented food, using the response surface methodology. B. amyloliquefaciens SRCM115785 was selected as the protease producer by productivity analysis and identified by 16S rRNA gene sequencing. Plackett-Burman design (PBD) was introduced to analyze the effect of each component on protease production among the 11 selected medium components. As a result, glucose, yeast extract, and beef extract were finally selected as factors for enhancing protease production. Central composite design (CCD) analysis was designed as a method to determine the optimal concentration of each component for protease production and the concentration of each medium composition for maximum protease production was predicted to glucose 6.75 g/l, yeast extract 12.42 g/l and beef extract 17.48 g/l. The suitability of the experimental model was proved using ANOVA analysis and as a result of quantitative analysis to prove this, the amount of increase was 230.47% compared to the LB medium used as a control. Through this study, the optimization of medium composition for enhancing protease production was established, and based on this, it is expected that it can be efficient use of protease as an industrial enzyme.

• 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).

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.509-513
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• 1991

Two Phytase-producing bacteria isolated from the fermented soybean and corn meals, Enterobacter cloacae and Bacillus lichenifomis, were used to investigate the degradation of phytic acid and changes of some nutrient contents in fermented soybean and corn meals. The pH in fermented soybean meal with E, cloacae was rapidly dropped after 48 hours, but the pH in fermented corn meal was declined gradually for 5 days. The degradation of phytic declined acid were optimized at $35^{\circ}C$.pH 8.0 for 5 days and at $30^{\circ}C$, pH 7.0 for 5 days fermented with E. cloacae and B. iichenifomis, respectively. Riboflavin and vitamin $B_{12}$ contents were greatly increased after the fermentation with these two bacteria, and also available lysine, methionine and tryptophan contents were greatly increased.

• The Microorganisms and Industry
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• v.14 no.2
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• pp.22-25
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• 1988

일반적으로 미생물들은 균종에 따라 독특한 색소를 생성하거나 수율이 낮다는 문제점을 갖고 있었다. 그러나 최근 발효기술의 발달및 유전자 재조합, 세포 융합등의 발달로 미생물 색소의 개발 가능성이 한층 높아졌다. 따라서 미생물에 의해 생산 가능한 천연색소에 대하여 그 현황과 전망을 개략적으로 기술하고자 한다.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.61-66
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• 2005

Korean traditional rice wine Takju and Yakju were manufactured using 2-step-brewing method. To investigate microflora involved in fermentation step, number of microorganisms, pH, titratable acidity, and alcohol contents of Takju and Yakju were measured. In Takju and Yakju, although not significantly, $1.1{\times}10^{8}$ and $2.0{\times}10^{6}\;CFU/mL$ lactic acid bacteria at initial stage of second fermentation decreased to $8.3{\times}10^{6}\;and\;1.0{\times}10^{4}\;CFU/mL$ at the end of second fermentation, respectively. For Takju, micrococci and yeast occupied 80 and 20% at initial stage of second fermentation, whereas bacteria and yeast occupied 35 and 65% at the end of second fermentation, respectively. Yeast occupied 88% throughout the second fermentation of Yakju. The main yeast isolated from both Takju and Yakju was identified as Saccharomyces cerevisiae using API 20C AUX kit. The yeast strain Candida magnoliae was also detected during fermentation of Takju and Yakju.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.926-931
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• 2011

Among various techniques for hydrogen production from organic wastewater, a dark fermentation is considered to be the most feasible process due to the rapid hydrogen production rate. However, the main drawback of it is the low hydrogen production yield due to intermediate products such as organic acids. To improve the hydrogen production yield, a co-culture system of dark and photo fermentation bacteria was applied to this research. The maximum specific growth rate of R. sphaeroides was determined to be $2.93h^{-1}$ when acetic acid was used as a carbon source. It was quite high compared to that of using a mixture of volatile fatty acids (VFAs). Acetic acid was the most attractive to the cell growth of R. sphaeroides, however, not less efficient in the hydrogen production. In the co-culture system with glucose, hydrogen could be steadily produced without any lag-phase. There were distinguishable inflection points in the accumulation of hydrogen production graph that resulted from the dynamic production of VFAs or consumption of it by the interaction between the dark and photo fermentation bacteria. Lastly, the hydrogen production rate of a repeated fed-batch run was $15.9mL-H_2/L/h$, which was achievable in the sustainable hydrogen production.

• Food Science and Preservation
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• v.13 no.3
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• pp.304-309
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• 2006

In order to examine the antimicrobial effect on dairy processing facilities and products, Prunus mume extinct (PME) was applied to the pilot plant system of dairy industry and yogurt, PME showed thermal and pH stability in the wide spectrum of temperature ($40{\sim}150^{\circ}C$) and pH ($4{\sim}10$) and remarkable antimicrobial activities against dairy spoilage microorganisms. As the result of aseptic treatment of dairy processing facilities with PME microbial colony including coliform bacteria was not detected canpore to those detected in the control. In the level of PME concentration which inhibit the growth of putrefactive microorganisms we could produce yogurt with good scores of sensory evaluation.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.506-511
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• 2009

In order to improve the bacterial cellulose(BC) production yield, centrifugal and inclined centrifugal impellers were developed. A 6 flat-blade turbine impeller was used as a control system. The flow pattern in the fermenter and volumetric oxygen transfer coefficient($k_La$) of these fermentation systems were studied. Fermentations were carried out for the production of BC by G. hansenii PJK in a 2-L jar fermenter equipped with new impellers. Liquid medium was circulated from the bottom, through the cylinder of the impeller and to the wall. The volumetric oxygen transfer coefficients, $k_La$, of inclined centrifugal and centrifugal impeller systems at 100 rpm were 23 and 15% of the conventional turbine impeller system, respectively. However, the conversion of microbial cells to cellulose non-producing mutant decreased and this results in the increase in BC production at low rotating speed of impellers.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.246.3-247
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• 1979

우유를 원료로하여 만든 치-즈나 발효유에는 Streptococcus나 Lactobacillus와 같은 유산균이 주로 사용되는데 이러한 제품에 발효가 많이 존재한다는 것이 보고되어 있으나, 그 존재의의에 대해서는 아직 불명한 점이 많다. 따라서 본 실험에서는 발효유에 존재하는 효모의 역활을 검토하기 위하여, 발효유제품의 starter로 사용되는 Lactobacillus와 효모 Saccharomyces fragillis 그리고 Deba-ryomyces hansenii 사이에 어떠한 상호작용이 있는지 를 알아보았다. 본 실험에 사용한 유산균수는 L.casei와 L. bulgaricus를 시판발효유제품에서 분리하였고 효모균수는 당학과 보존중인 D. hansenii, S. fragilis를 사용하였다. 유산균과 효모에 대한 단독배양과 혼합배양을 실시하고, 온도와 배양기간중에 나타나는 생균수와 산도변화를 관찰하였다. 유산균의 생균수 측정에는 B.C.P agar, 효모는 Y.M agar를 사용하였다. 산도는 일반분석법에 준하여 실시하였다.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.278-282
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• 1988

Rice straw was used in the acetone-butanol fermentation by semultaneous saccharification and fermentation (SSF) using Clostridium acetobutylicum and cellulolytic enzyme. Over 230 mM of solvent was produced from alkali treated rice straw of from ball-milled microcrystalline cellulose whilst only acidic fermentation products were formed from ball-milled rice straw. From the results it is concluded that rice straw used in the study contained an inhibitor for the solventogenesis by the organism which is insoluble in water and some organic solvent and destroyed by alkaline treatment.