マイクロコンピュータ制御法による高濃度菌体生産
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概要
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In the techniques used for high density cultivation of biomass, nutrients (oxygen, carbon, nitrogen, phosphorous, metal ions, etc.), physical and chemical factors (pH, temperature, viscosity, mass-transfer rate, etc.) and products are supposed to be growth-limiting factors. We developed automatic controlled-feed systems for nutrients and grew microorganisms to high densities when factors were maintained at suitable levels for growth. Protaminobacter ruber (methanol as a carbon source), Candida brassicae (ethanol), and Escherichia coli (glucose) were used.A DO-stat system was used for feeding the carbon source and oxygen into medium. The dissolved oxygen tension (DO) increased abruptly when the carbon source in the medium became a growth-limiting factor, and then decreased to the previous level when a carbon source was added. These phenomena were used as an indicator for feeding the carbon source in the DO-stat system. In a DO-stat employing a microcomputer, agitation speed and air and oxygen flow rates were automatically varied to keep the DO level constant during cultivation in cases of slow and abrupt Do changes due to carbon source deficiency.Methanol was detected and controlled with a silicone rubing sensor system. Methanol permeating through the wall of the silicone tubing immersed in the culture broth was detected by a FID of a gas chromatograph, and the output from the FID was used as an indicator of methanol concentration.When pH was controlled at a constant level with aqueous ammonia, the nitrogen content in the supernatant of the broth was maintained at a constant level during cultivation. Feeding of other nutrients, inorganic phosphorus and various kinds of metals, was coupled with the aqueous ammonia feed system.By feeding carbon sources and other nutrients using this system the cell density reached 112 (P. ruber), 125 (E. coli), and 268 (C. brassicae) g dry cells per liter.
- 社団法人日本生物工学会の論文
- 1985-05-25