Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9604248 | Journal of Biotechnology | 2005 | 10 Pages |
Abstract
A continuous acetone-butanol-ethanol (ABE) production system with high cell density obtained by cell-recycling of Clostridium saccharoperbutylacetonicum N1-4 has been studied. In conventional continuous culture of ABE without cell-recycling, the cell concentration was below 5.2 g lâ1 and the maximum ABE productivity was only 1.85 g lâ1 hâ1 at a dilution rate of 0.20 hâ1. To obtain a high cell density at a faster rate, we concentrated the solventogenic cells of the broth 10 times by membrane filtration and were able to obtain approximately 20 g lâ1 of active cells after only 12 h of cultivation. Continuous culture with cell-recycling was then started, and the cell concentration increased gradually through cultivation to a value greater than 100 g lâ1. The maximum ABE productivity of 11.0 g lâ1 hâ1 was obtained at a dilution rate of 0.85 hâ1. However, a cell concentration greater than 100 g lâ1 resulted in heavy bubbling and broth outflow, which made it impossible to carry out continuous culture. Therefore, to maintain a stable cell concentration, cell-bleeding was performed together with cell-recycling. At dilution rates of 0.11 hâ1 and above for cell-bleeding, continuous culture with cell-recycling could be operated for more than 200 h without strain degeneration and the overall volumetric ABE productivity of 7.55 g lâ1 hâ1 was achieved at an ABE concentration of 8.58 g lâ1.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Bioengineering
Authors
Yukihiro Tashiro, Katsuhisa Takeda, Genta Kobayashi, Kenji Sonomoto,