n-Butanol Production from Acid-Pretreated Jatropha Seed Cake by Clostridium acetobutylicum

n- Butanol fermentation using Clostridium strains suffers from low titers due to the inability of the strains to tolerate n -butanol. The current study demonstrates a process to get high titer of n -butanol in a single batch mode from the renewable feedstock jatropha seed cake by employing Clostridium acetobutylicum . Chemical mutagenesis was done for improvement of the strain for better n -butanol tolerance and production. Optimization of the parameters resulted in 13.2 g L −1 of n -butanol in 120 h using acid-treated jatropha seed cake hydrolysate (7 % w / v ) in anaerobic sugar medium. The process was scaled up to 15 L level, yielding 18.6 g L −1 of n -butanol in 72 h. The strain was found to be tolerant up to 30 g L −1 n -butanol under optimized conditions. The n -butanol tolerance was accompanied by over-expression of the stress response protein, GroEL, change in fatty acid profile, and ability to accumulate rhodamine 6G in the strain. The study has a significant impact on economically producing n -butanol from biomass.