Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/1998
Publication Date: N/A
Technical Abstract: In 1996, about 1.1 billion gallons of ethanol were produced in the United States, of which 95% was derived from fermentation of corn starch. We are investigating corn fiber as a novel fermentation feedstock. Corn fiber, a low value co-product generated during wet milling, is desirable as a feedstock because it is centrally stockpiled, low in naturally occurring inhibitors, and contains over 50% w/w carbohydrates. We have developed a process for conversion of corn fiber into ethanol. In the first step, the non-cellulosic carbohydrates are hydrolyzed into monomers using a small pilot scale jet syphon batch reactor. Sulfuric acid is used as a catalyst and direct steam used to heat the slurry to 150 deg C. The residual fibers are removed with a basket centrifuge and the supernatant neutralized with calcium hydroxide. The hydrolysate contains a mixture of arabinose, glucose, and xylose with a total sugar concentration of over 8% w/v. The hydrolysate is converted into ethanol using recombinant Escherichia coli; either K011 or FBR3, a novel strain developed in this laboratory. Ethanol yields average 0.45 g ethanol per g of sugar in the hydrolysate.