• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.557-562
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• 2002

Physiological characteristics such as specific productivity, morphology of Streptomyces cells Immobilized on celite beads, and operational stability at different dilution rates were investigated in continuous immobilized-cell cultures for the production of kasugamycin. At a dilution rate (D) of 0.05 $h^{-1}$, a relatively high specific productivity was attained and the loss of cell-loaded beads was negligible. At D=0.1 $h^{-1}$, a higher specific productivity and cell concentration could be obtained, resulting in a significantly improved volumetric kasugamycin productivity. However, no stable operation could be maintained due to a significant loss of cell-loaded beads from the reactor that was caused by their fluffy morphology developed in the later stage. At D=0.2 $h^{-1}$, the production of kasugamycin and cell growth were observed to be severely inhibited by the high concentration of residual maltose.

• 식물조직배양학회지
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• 제21권1호
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• pp.47-53
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• 1994

본 실험은 포도와 미국자리공의 세포현탁배양계에서 세포생장과 athocyaninn 및 betacyanin 색소생성에 미치는 광의 영향을 조사하였다. 그 결과, 포도의 세포현탁배양계에서의 세포증식 패턴은 광의 효과가 미약하였으나, 미국자리공의 경우는 암배양에 비하여 광조사구에서 뚜렷한 세포증식 패턴을 나타내었다. 포도세포는 12일간의 배양기간중 한번의 생장 피크를 보여주는데 비하여 미국자리공의 배양세포는 두 번의 증식 피크를 보여 광이 세포의 생장 및 분열 주기를 촉진시킬 뿐만 아니라 색소의 축적도 촉진시키는 것으로 나타났으며, 미국자리공 배양세포는 배양 후 4일째에 액포화에 따른 색소의 축적이 확인되었다. 한편, 색소생성에 미치는 광의 영향은 포도 현탁배양계에서는 배양후 6일째부터 생성되기 시작하여 배양 후 10일 전후에 최고치를 보이는데 비하여, 미국자리공의 현탁배양계에서는 세포증식 패턴에 따라 배양 후 4일째와 8일째에 두 번의 피크를 보였다. 그러나 이들 두 가지 모두 암배양하에서는 거의 색소 생합성이 이루어지지 않고 광상태하에서만 색소의 축적을 볼 수 있었다. 한편, 포도 세포배양계에서는 배양 후 4일째에 처리한 광은 약간의 효과가 있었으나, 배양 후 7일째 12시간 이상의 광에 의하여 색소생성이 크게 촉진되는 것을 알 수 있었다. 미국자리공의 경우에는 배양 후 7일 째보다는 오히려 배양 후 4일째에 광이 더욱 효과적이었다. 이상의 사실은 이들 두 가지 색소의 생합성과정에는 광이 절대적으로 필수적이지만 광을 필요로 하는 시기 및 요구하는 광량 등이 서로 다르다는 것을 시사해 준다.

• KSBB Journal
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• 제6권4호
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• pp.389-394
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• 1991

Emulsan is an extracellular emulsifying agent produced by the hydrocarbon-degrading Acinetobacter species RAG-1. In this study emulsan production of Acinetobacter calcpaceticus RAG-1 was investigated under various culture modes such as batch, fed-batch, membrane cell recycle, and continuous culture. The productions of emulsan under both ethanol-sufficient fed-batch and membrane cell recycle cultures were all 15.0U/ml, which was 53% increase in emulsan activity compared to that of pH controlled batch culture. Emulsan production was found to be strongly dependent on the residual ethanol concentration. In continuous culture the emulsan productivity increased with dilution rate.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.306-312
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• 2006

Two culture modes, continuous and semi-continuous, of the decolorization fungus, Geotrichum candidum Dec 1, were compared to obtain a high treatment efficiency of molasses decolorization and a large productivity of peroxidase (DyP) to simultaneously decolorize dyes and molasses. The continuous culture of G. candidum Dec 1 using a 5-I jar-fermentor showed high DyP activity at a low dilution ratio of $0.005h^{-1}$, and decolorization ratio of molasses of 80% was obtained concomitantly. Therefore, a semi-continuous culture was performed by repeated refill and draw. In this mode, approximately 1.5 liters of the culture broth was replaced per cycle when the decolorization ratio of molasses was near 80%. The molasses medium (1.0 liter per day) was treated and the peroxidase productiveity in the drawn culture broth was 26.6U/day, whereas the peroxidase productiveity was 17.9U/day in the continuous culture with a dilution rate of $0.005h^{-1}$. The semi-continuous treatment system was an efficient decolorization method for the strain, G. candidum Dec 1.

• 성인간호학회지
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• 제24권6호
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• pp.569-579
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• 2012

Purpose: The purpose of this study was to investigate the relationship between drug dosage calculation error prevention competence and medication safety organizational climate. Methods: We surveyed 207 nurses from 15 hospitals. An assessment survey was designed to assess the medication safety organizational climate which consisted of four subcategories including medication safety cultures, medication safety initiatives, medication error communication, and medication error management competence. The drug dosage calculation error prevention competence contains two subcategories; Dosage calculation habits and ability. The data were collected from July to August 2011. Descriptive statistics, t-test, ANOVA, partial Pearson correlation coefficient, canonical correlation were used. Results: Organizational climate was related to dosage calculation error prevention competence with two significant canonical variables. The first canonical correlation coefficient was .53 (Wilks' ${\lambda}$=0.71, df=8, p<.001) and that of the second was .21 (Wilks' ${\lambda}$=0.96, df=3, p=.027). The first variate indicated higher perception of medication safety cultures, safety initiatives, error communication and error management competence were related to better dosage calculation habits. The second variate showed higher perception of medication safety cultures and lower medication error management competence were related to higher calculation ability. Conclusion: Continuous supporting strategies for medication safety organizational climate should be implemented to improve drug dosage calculation habits.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.242-242
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• 2003

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.319-323
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• 2005

This study is concerned with development of efficient culture methods for lactic acid fermentation of Lactobacillus sp. RKY2. The cell-recycle repeated batch fermentation using cheese whey and corn steep liquor as raw materials was tried in order to further enhance the productivity of lactic acid. In addition, fermentation efficiencies could be considerably enhanced by cell-recycle continuous culture. Through the cell-recycle repeated batch fermentation, lactic acid productivity was maximized to 6.34 $g/L{\cdot}h,$ which corresponded to 6.2 times higher value than that of the batch fermentation. During the cell-recycle continuous fermentation, the last dry cell weight at the end of fermentation could be increased to 25.3 g/L.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.194-199
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• 2001

Chlorella kessleri cultivated in artificial wastewater using diurnal illumination of 12h light/12h dark (L/D) cycles. The inoculum density was 10(sup)5 cells/mL and the irradiance in light cycle was 45$\mu$mol㎡s(sup)-1 at the culture surface. As a control culture, another set of flasks was cultivated under continuous illumination. Regardless of the illumination scheme, the total organic carbon (TOC) and chemical oxygen demand (COD) was reduced below 20% of the initial concentration within a day. However, cell concentration under the L/D lighting scheme was lower tan that under the continuous illuminating scheme. Thus the specific removal rate of organic carbon under L/D cycles was higher than that under continuous illumination. This result suggested that C. kessleri grew chemoorganotrophically in the dark periods. After 3 days, nitrate was reduced to 136.5 and 154.1mg NO$_3$-N/L from 168.1mg NO$_3$-N/L under continuous illumination and under diurnal cycles, respectively. These results indicate nitrate removal efficiency under continuous light was better than that under diurnal cycles. High-density algal cultures using optimized photobioreactors with diurnal cycles will save energy and improve organic carbon sources removal.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.522-527
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• 2005

Various processes which produce L-lactic acid using ammonia-tolerant mutant strain, Rhizopus sp. MK-96-1196, in a 3L airlift bioreactor were evaluated. When the fed-batch culture was carried out by keeping the glucose concentration at 30g/L, more than 140 g/L of L-lactic acid was produced with a product yield of 83%. In the case of the batch culture with 200g/L of initial glucose concentration, 121g/L of L-lactic acid was obtained but the low product yield based on the amount of glucose consumed. In the case of a continuous culture, 1.5g/L/h of the volumetric productivity with a product yield of 71% was achieved at dilution rate of $0.024\;h^{-1}$. Basis on these results three processes were evaluated by simple variable cost estimation including carbon source, steam, and waste treatment costs. The total variable costs of the fed-batch and continuous cultures were 88% and 140%, respectively, compared to that of batch culture. The fed-batch culture with high L-lactic acid concentration and high product yield decreased variable costs, and was the best-suited for the industrial production of L-lactic acid.

• Journal of Microbiology and Biotechnology
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• 제7권1호
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• pp.43-48
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• 1997

Three strains capable of degrading a chlorophenol were isolated by selective enrichment from soils contaminated with industrial wastewater. A Pseudomonas solanacearum TCP114 could use 2,4,6-trichlorophenol (TCP) as sole carbon and energy source, while two strains of Pseudomonas testosteroni CPW301 and Arthrobacter ureafaciens CPR706 could use 4-CP. All isolates also grew well on phenol. The degradation of one component by a pure strain was strongly affected by the presence of other compounds in the medium, CPW301 and CPR706 entirely lost the ability to degrade 4-CP and phenol in the presence of TCP. TCP114 also lost the ability to degrade phenol when 4-CP was added to the culture medium. These restrictions on the degradability could be overcome by employing defined mixed cultures (TCP114 and one strain of 4-CP degrading strains). All three components were successfully degraded by defined mixed cultures through their cooperative activities. It was also demonstrated that defined mixed cultures could be immobilized by using calcium alginate for the semi-continuous degradation of the three component mixture. Immobilization could not only accelerate the degradation rate, but also allowed the reuse of the cell mass several times without loss of the cells' degrading capabilities.