C. acetobutylicum NCIM 2877 was obtained from NCIM, Pune, India (National Collection of Industrial Microorganisms). Initially, sporulated cells were activated by heat shock at 80 C for 10 min. The activated spore culture (2.5 ml) was inoculated in 100 ml sterile Reinforced Clostridial Medium (RCM) in 125 ml air tight, anaerobic glass bottles and grown for 20 h at 37 C. After 20 h, the prepared inoculum (5% v/v) was used for batch experiments.