Intensified crude glycerol conversion to butanol by immobilized Clostridium pasteurianum

Butanol production from glycerol was investigated through Clostridium pasteurianum entrapped into polyvinyl alcohol particles. Using an optimized system, batch and repeated batch fermentations with free and entrapped cells were performed, respectively. In both systems, glycerol samples of different purity were tested. In repeated batch fermentations, process time decreased from 19.5 to 2.7 hours and butanol productivity increased 6.3 times (3.08 g.L-1.h-1) compared with the free-cell process, using pure glycerol. In the case of glycerol from biodiesel production, butanol productivity of 2.90 and 1.76 g.L-1.h-1 was achieved from glycerol 01 and glycerol 02, respectively. No cell growth or solvent production was observed when the same glycerols were used in free-cell fermentations.