Abstract:
Butanol is an attractive fuel since it can be used as a fuel additive to reduce petroleum fuel consumption. However, traditional acetone-butanol-ethanol (ABE) fermentation has limitations-low productivity, butanol toxicity on microorganisms, and unstable production. Therefore, to enhance ABE fermentation, the cell immobilization on porous materials has been applied. Immobilized cells have been used to maintain high cell concentrations and stability of cell operation during the fermentation process. Consequently, this research aimed to study ABE fermentation by immobilized Clostridium beijerinckii TISTR 1461 onto different porous materials. Brick, activated carbon, and zeolite were used as carriers for immobilization. Fermented product samples were collected at different times on stream to observe the productivity of the immobilized cells fermentation, and compared with the free mobilized cells fermentation process. Butanol production from immobilized cells fermentation on brick and zeolite were 9.5% and 62.0% higher, respectively, than free mobilized cells fermentation. Whereas, butanol production from immobilized cells fermentation on activation carbon was found to be lower than free mobilized cells 45.0%. There observed that the effect of materials to medium pH has play role on solvent production. Repeat batch fermentation with immobilized cell on zeolite for investigate cell efficiency was substantial and maintained after seven sequential reuse cycles. The average butanol production amounted to 6.5 g/1. Scanning electron microscopy (SEM) demonstrated that the Clostridium beijerinckii cells were present on the surface and in the pores of the materials.
