초록
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. 23gL<SUP>-1</SUP> glucose for 50gL<SUP>-1</SUP> rice straw solution) glucose. Anaerobic fermentation of rice straw hydrolyzate using Clostridium acetobutylicum NCIM 2337 resulted in production of 6.24gL<SUP>-1</SUP> of acetone, 13.5gL<SUP>-1</SUP> of butanol and only 0.82gL<SUP>-1</SUP> of ethanol. The net consumption of substrates was as follows: glucose 12.86gL<SUP>-1</SUP> (i.e. ~55%), total reducing sugar 18.32gL<SUP>-1</SUP> (~57%) and total sugar 24.5gL<SUP>-1</SUP> (~61%). Thus, higher solvents yield and significant sugar utilization makes rice straw a potential feedstock for biofuels production.