Submitted to: Bioprocess and Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2007
Publication Date: 7/3/2007
Citation: Qureshi, N., Saha, B.C., Cotta, M.A. 2007. Butanol production from wheat straw hydrolysate using Clostridium beijerinckii. Bioprocess and Biosystems Engineering. 30:419-427.
Interpretive Summary: Butanol is an important transportation fuel that has more energy content than ethanol. It can be used in existing gasoline supply and distribution lines, has higher octane number, and can be mixed with gasoline in any proportion. It is also a valuable chemical. Butanol can be produced from annual crops such as corn, rice, barley, and other starchy crops. However, due to the prohibitive cost of these grains and cereals, use of lignocellulosic residues is recommended. Microbial culture such as Clostridium beijerinckii P260 can utilize five and six carbon sugars present in cellulosic biomass and convert them to butanol. In order to reduce the cost of butanol production, we used wheat straw and cutting edge technology to convert it to butanol. Wheat straw was hydrolyzed to lignocellulosic component sugars (glucose, xylose, arabinose, galactose, and mannose) prior to their conversion to butanol. The rate of production of wheat straw hydrolysate to butanol was 214% over that from glucose. Successful production of economically available butanol from wheat straw by fermentation will benefit farmers, the butanol producing industry, and the United States public. Development of such a fuel by an economically viable process is essential as gasoline prices are rising steadily.
Technical Abstract: In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures using Clostridium beijerinckii P260. In control fermentation, 48.9 gL**-1 glucose was used to produce 20.1 gL**-1 ABE with a productivity and yield of 0.28 gL**-1h**-1 and 0.41, respectively. In a similar experiment where WSH (86 gL**-1) was used, the culture produced 25.0 gL**-1 ABE with a productivity and yield of 0.60 gL**-1h**-1 and 0.42, respectively. These results are superior to the control experiment, and productivity was improved by 214%. When WSH was supplemented with 35 gL**-1 glucose, a reactor productivity was improved to 0.63 gL**-1h**-1 with a yield of 0.42. In this case, ABE concentration in the broth was 28.2 gL**-1. When WSH was supplemented with 60 gL**-1 glucose, the resultant medium containing 128.3 gL**-1 sugars was successfully fermented (due to product removal) to produce 47.6 gL**-1 ABE, and the culture utilized all the sugars (glucose, xylose, arabinose, galactose, and mannose). These results demonstrate that C. beijerinckii P260 has excellent capacity to convert biomass derived sugars to solvents and can produce over 28 gL**-1 (in one case 41.7 gL**-1 from glucose) ABE from WSH.