• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.401-406
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• 1994

The medium compositions of Alcaligenes eutrophus were optimized for increasing PHB productivity. It is very important to optimize the concentrations of inorganic salts and trace eleme- nts as well as carbon and nitrogen sources to maximize cell growth rate and productivity. The fed-batch culture of Alcaligenes eutrophus by dual feeding of ammonia water and glucose under optimized initial medium concentrations was carried out. Glucose was fed manually according to glucose consumption rate and ammonia water by pH-stat. The final cell concentrations and PHB content in 30 hours were 122 g/l and 65% of dry cell weight(yielding 79 g of PHB/l), respectively and 2.64 g/l/hr of PHB production rate was obtained.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.207-211
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• 1997

Media optimization for the production of thermostable protease specifically hydrolyzing defatted soybean meal (DSM) from Bacillus licheniformis NS70 was performed by two methods, one-at-a-time method and response surface methodology (RSM). The best carbon source and nitrogen source for the protease production were lactose and DSM, respectively. The maximum protease production estimated by RSM was 606 U/L at 1.11% lactose and 0.43% DSM, the value of which was nearly consistent to the experimental value of 599 U/L. Yeast extract suppressed the protease production. The medium pH was slightly increased at the beginning stage of fermentation, and it tended to decrease after 8 hours. The optimal pH for the protease production was 7.2 in the batch fermentation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.768-776
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• 2011

This paper considers a data fitting problem for rational function models using the LM (Levenberg-Marquardt) optimization method. Rational function models have various merits on representing a wide range of shapes and modeling complicated structures by polynomials of low degrees in both the numerator and denominator. However, rational functions are nonlinear in the parameter vector, thereby requiring nonlinear optimization methods to solve the fitting problem. In this paper, we propose a data fitting method for rational function models based on the LM algorithm which is renowned as an effective nonlinear optimization technique. Simulations show that the fitting results are robust against the measurement noises and uncertainties. The effectiveness of the proposed method is further demonstrated by the real application to a 3D depth camera calibration problem.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.406-410
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• 1990

The influence of glucose concentration on cell growth rate and on the expression level of the strong promoter obtained from alkali-tolerant Bacillus sp. YA-14 chromosomal DNA was studied. In fed-batch culture, the promoter activity could be maximized by maintaining a very low level of glucose concentration in the broth and glucose consumption rate below 1.08g/g cell-h. The induction of the promoter was possible by addition of sporulation medium after the cell was grown in growth medium with only low level of CAT activity.

• KSBB Journal
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• v.6 no.1
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• pp.91-98
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• 1991

The media compositions and culture conditions were optimized for mycelial growth of Coriolus versicolor and Lentinus edodes. Media composition for optimal growth of Coriolus versicolor was 2.0% glucose 0.4% peptone and 0.6% yeast extract. Media composition for optimal growth of Lenttnus edodes was 2.0% glucose 2.0% starch 0.4% bacto-soytone and 0.6% yeast extract. The media supplemented with KH2PO4, 0.046% KH2PO4 0.1% and MgSO4, .7H2O 0.05% supported better mycelial growth than the media without mineral salts. The optimum temperature for mycelial growth ranged from $25^{\circ}C$-28$^{\circ}C$. The optimum pH range for mycelial growth of Coriolus versicolor was 5.2~5.6 while that of Lentinus edodes appeared to be 5.75.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.449-452
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• 2008

임베디드 시장의 급속한 성장은 임베디드 소프트웨어의 수요와 산업 비중을 크게 증가시켰다. 임베디드 시스템의 복잡성은 점점 증가하는 반면, 시장에서 요구하는 개발 기간은 점점 짧아지고 있다. 이로 인해 효율적인 임베디드 소프트웨어 개발 기술 및 개발 플랫폼, 최적화를 위한 분석 도구에 대한 수요도 날로 증가하고 있다. 본 논문에서는 임베디드 시스템을 위한 소프트웨어 통합 개발 환경인 Esto 플랫폼 기반의 $ETT^{esto}$ 플러그인을 통한 타겟 시스템 분석 및 모니터링 환경을 제안한다.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.307-310
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• 2004

본 연구에서는 분리대두단백(ISP: isolated soy protein)과 탈지대두박(DSF: defatted soy flake)을 Devolase Flavourzyme 효소로 가수분해한 각각의 HVP를 발효 배지로 사용하여 Candida utilis(KCCM 50342) 효모의 ethylalcohol, 4-ethylguaiacol의 생성과 향 생성의 주요 인자인 a -galactosidase의 활성을 측정하였다. Ethylalcohol은 발효 1일째에 탈지대두박을 원료로 하고 여과후 미생물 처리한 경우에서 가장 높게 생성되었고, 4-ethylguaiacol은 일부 여과하지 않고 미생물 처리한 경우에서 낮은 농도의 생성을 보였다. a-galactosidase 효소활성은 탈지대두박 보다 ISP를 원료로 한 HVP에서 높은 활성을 보였다. 관능검사결과 탈지대두박을 사용한 HVP의 관능적 특성이 ISP를 원료로 한 HVP보다 더 우수하였다. 결과적으로 탈지대두박을 원료로 한 HVP의 향기성분 및 관능적 특성이 우수함을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.470-473
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• 2006

생물학적 수소생산을 위해 토양으로부터 새로운 균주인 Enterobacter asburiae SNU-1이 분리되었다 이 균주의 경우 다른 균주와는 달리 미생물 생장과 수소생산 phase가 분리되는 특징을 가지고 있다. 이러한 정지기에서의 수소생산은 미생물 내에 존재하는 formate hydrogen lyase를 사응하여 formate 분해에 의해 일어난다. 따라서 본 연구에서는 미생물 생장 phase에서 formate hydrogen lyase가 발현된 미생물을 얻고 이를 formate만 있는 배지에서 수소생산 가능성에 대한 연구를 수행하였다. 앞으로 formate분해를 위한 조건을 최적화한다면 높은 수소생산성을 나타낼 것이라 기대된다. 또한, 이는 formate로부터 미생물촉매를 이용하여 수소를 생산하고 이를 연료전지로 공급하는 생물학적 reformer로써의 이용 가능성을 보여준다.

• KSBB Journal
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• v.14 no.5
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• pp.585-592
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• 1999

This study was aimed to enhance the Fe(II) oxidation rate using immobilized cells of Thiobacillus ferroxidans. For this purpose, a medium for the minimization of jarosite formation was developed first. Secondly, cell immobilization in celite beads was carried out. And then, repeated-batch and continuous operatons of Fe(II) oxidation by using immobilization cells were performed. In a series of flask cultures, three types of media were tested: media with a much lower salt concentration than that of the 9K medium; media which contained different nitrogen sources from that of the 9K medium, that is $(NH_4)_2HPO_4$, $NH_4Cl and HNO$_3$; media which contained $(NH_4)_2HPO_4$ as nitrogen and phosphate source, but without $K_2HPO_4$ as nitrogen and phosphate source in the 9K medium. As a result, the M16 medium which contained 3 g/L of $(NH_4)_2HPO_4$ as nitrogen and phosphate source was found to be the optimal one. It sustained good cell growth allowing no jarosite formation. In the repeated-batch operations, the rate of Fe(II) oxidation gradually increased to reach a maximum value as the batch was repeated. As a result of repeated-batch operations. a maximum Fe(II) oxidation rate was 2.33 g/L . h. In the continuous operations, the iron oxidation rate could be increased to 2.14 g/L .h at a dilution rate of 0.25 $h^{-1}$ which is greater than the maximum specific growth rate (0.12 $h^{-1}$) of the bacteria.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.627-633
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• 2016

Sweet sorghum [Sorghum bicolor (L)] is one of the major crops for biofuels such as sugarcane and sugar beet which raw materials rich in saccharide. Sweet sorghum juice was extracted from the stem. It's composed of fermentable sugars such as glucose, fructose and sucrose. Ethanol from the extracted sweet sorghum juice can be easily produced by yeast fermentation process. Sweet sorghum juice is consisted of not only sugars but also various nutrients like nitrogen and phosphate. For commercial production of bioethanol, seed culture is one of the important parts of fermentation, so that optimal culture medium should be selected for the reduction of processing costs. In this study, sweet sorghum juice was estimated as a culture medium for seed culture of cellulosic bioethanol. For the comparison of cultures with various substrates, it used YPD including each 5 g/L yeast extract and peptone, sweet sorghum juice and hydrolyzed Miscanthus was taken part in the culture with 2%, 5% and 10% sugar conditions. Based on media of YPD and sweet sorghum juice, cell-mass concentration was obtained maximum more than $2.5{\times}10^8CFU/mL$ after 24 h of cultivation. Consequently sweet sorghum juice is suitable for the cell culture with more than $1.0{\times}10^8CFU/mL$ after 12 h of cultivation. This can be used as a culture medium for the cellulosic bioethanol industry.