• KSBB Journal
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• v.16 no.1
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• pp.30-35
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• 2001

High cell density culture of Bacillus thuringiensis was conducted in fed-batch culture and TCRC using a bioreactor incorporating ceramic membrane filter. Cell growth of B. thuringiensis in fed-batch culture increased linearly, which was well matched by the results of cell growth modeling. In spite of the slower growth rate during fed-batch culture, no spore formation was observed, which was contrary to the results of continuous culture. Changing culture mode to batch culture after fed-batch operation induced a 2.7$\times$$10^9$ CFU/mL spore concentration using a 300 g/L glucose feed concentration. In TCRC operation incorporating ceramic filter within the bioreactor, the effect of glucose feed concentrations on the cell growth and spore formation of B. thuringiensis was determined. A maximum cell concentration of 1.8$\times$$10^{10}$ CFU/ml, which corresponds to 82.6 g-cell/L, was obtained in the TCRC using a 50 g/L glucose feed concentration. In the TCRC, cell growth increased linearly and glucose concentration was limited, which agreed well with the results of cell growth modeling. No spore formation was observed except when 1 g/L of glucose was fed. Changing to batch culture induced a 1.2$\times$$10^{10}$ CFU/mL of spore concentration, which was the highest spore concentration obtained among the various culture modes examined. The optimal glucose feed rate was found to be 0.55 g-glucose/h.

• Journal of Navigation and Port Research
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• v.26 no.5
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• pp.529-535
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• 2002

Design and implementation methodologies on the performance evaluation system of Two-Channel Ring-Core Flux-Gate Compass (TCRC FG-Compass) are described, with evaluation procedures and methods based on the polynomial regression models. Performance evaluation system consists of a step motor driving unit, a bearing transmitting unit and evaluation programs derived from polynomial regression formulae. Newly designed performance evaluation system enabled the accuracy of TCRC FG-Compass to be ascertained. It was confirmed that the size of residual deviation of TCRC FG-Compass is $2^{\circ}$, while that of the conventional one is $4^{\circ}$. In addition, the design methodology to the self estimation and correction of residual deviations is also discussed.

• KSBB Journal
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• v.16 no.3
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• pp.274-280
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• 2001

A serum-free media for CRIP/MFG-LacZ retrovirus production was developed and applied to continuous packed-bed culture system. The serum-free media developed by fractional factorial design contains indulin ($10\mug/mL$), transferrin ($5\mug/mL$), BSA (4 mg/mL), EGF (25 ng/mL), and linoleic acid ($10\mug/mL$). Operation of continuous packed-bed reactor using Fibra-cel enabled the packging cell to stably maintain retrovirus titer for about 1 week. The optimal operation conditions for dilution rate and temperature were 0.67(h(sup)-1) and $32^{circ}C$, respectively. Using this media, the retrovirus titer(cfu/mL) in the packed continuous culture was about 50% that of continuous culture with serum containing DMEM media.