Continuos IBE fermentation by immobilized growing Clostridium beijerinckii cells in a stirred‐tank fermentor

Abstract
The potential of continuous isopropanol–butanol–ethanol (IBE) fermentation by Ca–alginate-immobilized Clostridium beijerinckii cells in a continuous stirred-tank reactor is investigated. A mathematical model is presented to describe steady-state reactor performance. It appeared to be possible to use the biocatalyst particles repeatedly for successive fermentations (at least three times for a total duration of two months). Reactor productivity was 6–16 times higher than that of a batch fermentation (free cells), while the solvents yield was also increased. Measurements of substrate, product, and biomass concentrations were only partially in agreement with the model; however, a solid basis for further technological developement of the process has been laid.