Biobutanol has recently emerged as a potential alternate liquid fuel for gasoline and diesel. In this work,
we have studied clostridial fermentation of stress assisted-acid hydrolyzed rice straw that exhibited a
typical trend of acidogenesis followed by solventogenesis. Acid hydrolysis of 5% (w/v) mixture of rice
straw in water with simultaneous application of shearing stress resulted in release of 3.9% (w/v) total
sugar out of which 3.1% (w/v) was reducing sugar. Glucose formed major fraction (75%) of the reducing
sugar (or 2.3% w/v total sugar). Thus, essentially, 5% (w/v) of rice straw solution released nearly 46% (w/
w) (i.e. 23 g L1 glucose for 50 g L1 rice straw solution) glucose. Anaerobic fermentation of rice straw
hydrolyzate using Clostridium acetobutylicum NCIM 2337 resulted in production of 6.24 g L1 of acetone,
13.5 g L1 of butanol and only 0.82 g L1 of ethanol. The net consumption of substrates was as follows:
glucose 12.86 g L1 (i.e. 55%), total reducing sugar 18.32 g L1 (57%) and total sugar 24.5 g L1
(61%). Thus, higher solvents yield and significant sugar utilization makes rice straw a potential feedstock
for biofuels production.