Abstract

Transportation biofuel ethanol was produced from xylose and corn fiber hydrolyzate (CFH) in a batch reactor employing Escherichia coli
FBR5. This strain was previously developed in our laboratory to use cellulosic sugars. The culture can produce up to 49.32 g L-1
ethanol
from approximately 125 g L-1 xylose. Use of commercial nutrient sources such as corn steep liquor (CSL) and soy peptone (SP) was also
studied and SP was found to be superior than CSL. SP at a concentration of 15 g L-1
resulted in the production of 42.2 g L-1
ethanol with
ethanol yield and productivity of 0.49 and 0.74 g L-1 h
-1
, respectively. Corn fiber (CF) was pretreated with dilute H2SO4 and hydrolyzed
using commercial cellulases. Employing CFH as a sole substrate, the culture produced 35.33 g L-1
ethanol with a productivity and yield of
1.01 g L-1 h
-1
and 0.54, respectively, leaving behind no residual sugars in the medium. This productivity is 40 % higher than when using
xylose as the carbon source in the control experiment.

Key words: corn fiber, corn fiber hydrolyzate, ethanol, productivity, yield, Escherichia coli FBR5