• KSBB Journal
• /
• 제4권2호
• /
• pp.74-77
• /
• 1989

Volumetric productivity를 향상시키기 위하여 미생물 재순환에 의한 연속 시스템을 이용하였다. 연속발효조의 연구에서 9.2g/1와 15.0,g/1의 범위의 세포 농도를 유지할 수 있었다. 4%의 xylose의 feed와 1.04g $O{_2}$hr-g DCW의 specific oxygen supply rate의 조건에서 희석율이 0.0349 h$^{-1}$ethanol 수율은 0.36이었다. Ethanol volumetric productivity는 같은 희석율에서 0.244g/hr-$\ell$로 증가하였으며 이것은 회분배양값의 260%이었다.

• KSBB Journal
• /
• 제14권2호
• /
• pp.188-191
• /
• 1999

본 실험에서는 하이브리도마세포 배양 중 아미노산 량의 변화를 조사하여 세포성장, 세포대사 및 항체생산성에 미치는 아미노산의 영향을 조사하였다. 실험결과에 의하면 vR8 하이브리도 마세포 배양 중 세포성장이 급속히 이루어지는 시점과 최대 세포농도에 도달한 시점에서의 glutamine, arginine, leucine 등 다수 아미노산의 고갈이 관찰되었고, 이후 세포활성이 급속히 저하되었다. 이때 glucose 농도, lactate, armmonia 등의 대사산물 농도 및 pH, DO, 교반속도 등은 적절하게 유지되었기 때문에 이들 요소에 의한 세포성장의 저해는 없었다. 따라서 이들 아미노산의 고갈이 세포활성의 저하에 커다란 영향을 주었다고 생각된다. 한편, 고갈된 아미노산을 첨가한 배지(GC-HY-S2)로 배양을 해본 결과 세포농도를 $2.91\times10^7$cell/mL까지 증가시킬 수 있었다. 즉, 변형배지에서는 세포활성의 저하를 가져오는 세포성장구간을 지나 계속적인 세포성장을 보여 27배 정도 더 높은 최대 세포농도를 보였다. 세포농도의 증가로 specific productivity, volumetric productivity도 각각 1.75배, 56배 증가하였다. 최대 세포농도에서의 아미노산 량을 조사한 결과를 보면 충분한 양의 아미노산이 공급되었음을 알 수 있다. 고농도 하이브리도마세포 배양에서의 일부 아미노산의 고갈은 일반적으로 관찰되는 현상이다. 그러므로 세포를 고농도로 배양하기 위해서는 아미노산 분석을 통해 고갈된 아미노산을 첨가해 주어야 하는데, 아미노산의 요구는 세포주마다 다르므로 배지 최적화과정에서 아미노산 분석에 의한 배지의 개선이 필요하다고 생각된다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.917-921
• /
• 2000

One of the major limitations of productivity and quality in machining is machining accuracy of the machine tools. The machining accuracy is affected by geometric, volumetric errors of the machine tools. This paper suggests the enhancement method of machining accuracy for precision machining of high quality metal reflection mirror or optics lens, etc. In this paper, we study 1) the compensation of linear pitch error with NC controller compensation function using laser interferometer measurement, 2) the method for enhancing the accuracy of NC milling machining by modeling and compensation of volumetric error, 3) the generation of the parabolic face profile. And the method is verified by the parabolic face machining experiment with a vertical three axes NC milling machine. After this study, we will inspect using On-machine measurement and study the repetitive machining by a compensated path

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권1호
• /
• pp.1-5
• /
• 2001

The potential use of spin filter device to retain Propionibacterium acidipropionici in the bioreactor under continuous mode of fermentation, and improve acid productivity, was examined. The yield of propionic acid based on lactose concentration was 51% in batch and 54% in continuous (dilution rate = 0.05 h(sup)-1) operation. The yield in continuous fermentation with cell retention using spin filter of 10 micron size (dilution rate = 0.05 h(sup)-1) was even higher at 70% (w/w). The volumetric productivity under batch and continuous mode of operation were 0.312g L(sup)-1 h(sup)-1 and 0.718g L(sup)-1 h(sup)-1 respectively. Continuous fermentation with cell retention demonstrated even higher volumetric productivities at 0.98g L(sup)-1 h(sup)-1 with out clogging problems. It could be used for utilization of cheese whey to produce propionic acid at higher yield and productivities.

• 한국미생물·생명공학회지
• /
• 제18권5호
• /
• pp.525-529
• /
• 1990

식물세포인 Lithospermum erythrorhizon을 교반 반응기와 calcium alghinate에 고정화된 상태로 충전층 반응기에서 n-hexadecane으로 동시 추출하면서 shikonin을 생산하여 각각의 생산성을 비교하였다. 교반 반응기에서 shikonin의 비생산과 부피생산성은 각각 1.5mg shikonin/g cell과 400$\mu g$ shikonin/(L.day)였고 충전층 반응기에서는 가각 2.0mg shikonin/g cell과 2857 $\mu g$ shikonin/(L.day)였으며 이는 각각 교반 반응기에 비하여 1.3, 7.1배 높은 것이다. 충전층 반응기에서 shikonin의 생산성이 높은 것은 calcium alginate 입자에 세포가 고농도고 축적되어 단위 반응기 부피당 세로의 부하 능력이 높고 또한 세포가 서로 접촉하기가 쉽고 고정화 입자내의 환경이 세포가 분화하기에 좋은 조건을 형성하기 때문인 것으로 사료된다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제11권6호
• /
• pp.544-549
• /
• 2006

The performance of immobilized fungal cells on celite beads for the production of gibberrelic acid was investigated in flasks and 7-L stirred-tank reactor. Repeated incubations of immobilized fungal cells increased cell concentrations and volumetric productivity. The maximum volumetric productivity obtained in the immobilized-cell culture was 3-fold greater than that in suspended-cell culture. The concentration of cotton seed flour (CSF), among the various nutrients supplied, most significantly influenced productivity and operational stability. Notably, insoluble components in CSF were found to be essential for production. CSF at 6 g/L with 60 g/L glucose was found to be optimal for gibberellic acid production and stable operation by preventing excessive cell growth.

• 한국미생물·생명공학회지
• /
• 제19권3호
• /
• pp.272-280
• /
• 1991

유가식 배양에서 배지첨가속도가 하이브리도마 세포의 증식과 항체생성속도에 미치는 영향을 조사하였다. 항체 비생성속도 $q_p$값이 변화는, 회분식 배양의 경우 배양 초기에 가장 높았다가 계속 감소하는 경향을 보였으나, 배양 48시간 이후부터 배지의 첨가가 시작되는 유가식 배양에서는 qp 값이 배지 첨가직후 부터 빠른 속도로 증가하기 시작해 배양이 끝날 때까지 높은 값으로 유지되었다. 그리고 배지의 비첨 가속도 $q_f$가 증가되면서 항체의 비생성속도 $q_p$도 민감하게 증가하는 경향을 보였다. 생성된 최종 항체농도 $C_{final}$은 배지 첨가속도에 비해 큰 영향을 받지 않고 거의 비슷한 값을 보였지만 평균적으로 회분식 배양보다는 그 값이 3배 이상 증가되어 최고 220$\mu g$/ml까지 향상되었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.75-76
• /
• 2023

The construction industry's lack of experience and expertise makes it difficult for projects to realize the full benefits of implementing modular construction. Such project performance-hindering elements are often labeled as modular challenges. The added requirement for the transportation of the finished volumetric module is one aspect of the 'module transportation logistics,' the under-researched modular challenge that can prevent projects from incurring maximum cost and productivity benefits. The typical module transportation phases include lifting, transporting, and offloading. From conducting a literature review, this paper aims to investigate the equipment commonly adopted to lift and offload the module and validate its economic efficiency by comparing it with the alternative lifting/offloading equipment used in the two case projects. The results showed that hydraulic jacks are an economic alternative to the crane for lifting/offloading the module. The increase in single-module projects with smaller budgets made crane usage economically undesirable, and this study suggested a viable option for a more economical alternative.

• Journal of Plant Biotechnology
• /
• 제4권3호
• /
• pp.109-115
• /
• 2002

Submerged cultures of Ganoderma lucidum, a valuable mushroom in traditional Chinese medicine, were used for production of bioactive Banoderic acids and Ganoderma polysaccharides. The significant effects of oxygen supply were demonstrated in both shake flasks and bioreactors. By changing the medium loading volume in a shake flask, a different value of initial volumetric oxygen transfer coefficient ($K_L$a) was obtained, and a higher $K_L$a value led to a higher biomass density and a higher productivity of both intracellular polysaccharide and ganoderic acid. In a stirred bioreactor, at an initial $K_L$a of 78.2 $h^{-1}$, a maximal cell concentration of 15.6 g/L by dry weight was obtained, as well as a maximal intracellular polysarcharide (IPS) production of 2.2 g/L and its maximal productivity of 220 mg/(L.d). An increase of initial $K_L$a led to a higher production and productivity of GA, and the GA production and productivity at an initial $K_L$a of 96.0 $h^{-1}$ was 1.8-fold those at an initial $K_L$a of 16.4 $h^{-1}$. The fundamental information obtained in this study may be useful for efficient large-scale production of these valuable bioactive products by the submerged cultures.

• 한국미생물·생명공학회지
• /
• 제47권3호
• /
• pp.381-389
• /
• 2019

Chlorella vulgaris was isolated from the Nile River, Qalubia Governorate, Egypt, for possible use in biodiesel production. BG-II nutrient growth media was used for isolation and laboratory growth. Identification was performed via 18S rRNA gene amplification, followed by sequencing. The alga was exposed to UV-C (254 nm) for 15, 30, and 45 s to improve dry weight accumulation and to increase the oil production. Daily measurements of dry weight ($g{\cdot}l^{-1}$) were performed; oil content and volumetric lipid productivity were also determined. UV-C exposure led to an increase in the volumetric lipid productivity by 27, 27.3, and $32.4mg{\cdot}l^{-1}{\cdot}d^{-1}$ with 15, 30, and 45 s, respectively, as compared with the control, which resulted in $18mg{\cdot}l^{-1}{\cdot}d^{-1}$. Of the examined mutants, the one with the highest productivity was re-irradiated by UV-C (254 nm) for 15, 30, 45, and 60 s. For 15 s of exposure time, the oil content increased to 34%, while it was 31% at 30 s; further, it decreased to 22% at 45 and 60 s exposures. The fatty acid methyl ester profile was 82.22% in the first mutant at 45 s, compared with the wild strain that contained a total of 66.01% of FAs. Furthermore, the highest levels of polyunsaturated fatty acid methyl ester were observed in the mutant exposed for 45 s, and it reached 11.41%, which reduced the cetane number to 71.3.