Reactor design for the ABE fermentation using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar

Cells of Clostridium acetobutylicum were immobilized by adsorption onto bonechar. and used for the production of solvents (ABE fermentation) from whey permeate. When the process was performed in packed bed reactors operated in a vertical or inclined mode, solvent productivities approximating 6 kg/(m³h) were obtained. However, the systems suffered from blockage due to excess biomass production and gas hold-up. These problems were less apparent when a partially-packed bed reactor was operated in the horizontal mode. A fluidized bed reactor proved to be the most stable of the systems investigated, and a productivity of 4.8 kg/(m³h) was maintained over a period of 2000 h of operation. The results demonstrate that this type of reactor may have a useful future role in the ABE fermentation.