Wheat Straw for Biobutanol Production

Scientists from the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) have reported the production of biobutanol (butyl alcohol) from wheat straw.  Biobutanol is considered to be an important biofuel because of its higher energy content, and a higher octane number relative to ethanol; (a high octane number is considered desirable in gasoline engines).  It could also be blended with gasoline in any proportion.  The process involves the pre-treatment of the wheat straw by dilute sulphuric acid to improve accessibility of cellulose to hydrolytic enzymes.  The pretreated wheat straw then undergoes the following processes which have been combined in a single step: (1) enzymatic hydrolysis using hydrolytic enzymes, known as “carbohydrases” to break down the cellulose into simple 5-carbon or 6-carbon sugars, and (2) a combined fed-batch fermentation/gas stripping process to convert the sugars into butanol without product inhibition.  Fermentation was accomplished by using the microorganism, Clostridium beijerinckii and product recovery was accomplished by gas stripping.  The simultaneous saccharification, fermentation and product recovery is an interesting feature of the research, and is reported in the Proceedings of the 29th Symposium on Biotechnology for Fuels and Chemicals.

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Information about octane number from Wikipedia
http://en.wikipedia.org/wiki/Octane_number