Production of Butanol from Palm Empty Fruit Bunches Hydrolyzate by Clostridium Acetobutylicum

This study aimed to produce biofuel, namely biobutanol, from palm empty fruit bunches (PEFB) by Clostridium acetobutylicum. The PEFB was hydrolyzed either by acid or enzyme to produce available sugar for C. acetobutylicum. For acid hydrolysis, 50 g/L was hydrolyzed by sulfuric acid at various concentrations of acid in a range of 0 to 2.0%. Increasing the concentration of acid from 0.5 to 2.0% provided reducing sugar concentration of 44 to 49 g/L. Prior to enzymatic hydrolysis by cellulase, the PEFB was pretreated either with acid or base or both chemicals. The cellulose content of the PEFB was increased from 41.32 ± 0.81% up to 62.97 ± 0.32, 62.70 ± 0.35 and 68.40 ± 0.89% by the pretreatment with acid, base and both chemicals, respectively. Consequently, 50 g/L of the pretreated PEFB was hydrolyzed by cellulase for 72 hours. The amounts of obtained reducing sugar from acid, base and both pretreated PEFB were 10.14 ± 0.14, 16.43 ± 0.40 and 6.50 ± 0.23 g/L respectively. The pretreatment by base was found to be the most suitable method to prepare PEFB for enzymatic hydrolysis. The production of acetone butanol ethanol by C. acetobutylicum in RCM medium containing 20 g/L sugar from cellulase hydrolyzed PEFB at 168 hours gave higher total ABE production of 1.262 ± 0.218 g/L compared with that from acid hydrolyzed PEFB (1.058 ± 0.173 g/L).