Fermentation of "Quick Fiber" produced from a modified corn-milling process into ethanol and recovery of corn fiber.

Approximately 9% of the 9.7 billion bushels of corn harvested in the United States was used for fuel ethanol production in 2002, half of which was prepared for fermentation by dry grinding. The University of Illinois has developed a modified dry grind process that allows recovery of the fiber fractions prior to fermentation.

Engineering lactic acid bacteria with pyruvate decarboxylase and alcohol dehydrogenase genes for ethanol production from Zymomonas mobilis.

Lactic acid bacteria are candidates for engineered production of ethanol from biomass because they are food-grade microorganisms that can, in many cases, metabolize a variety of sugars and grow under harsh conditions. In an effort to divert fermentation from production of lactic acid to ethanol, plasmids were constructed to express pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH), encoded by the pdc and adhB genes of Zymomonas mobilis, in lactic acid bacteria. Several strains were transformed with the plasmids, and transcription of pdc and adhB was confirmed by northern hybridization analysis of transformants.

Optimization of SO2-catalyzed steam pretreatment of corn fiber for ethanol production.

A batch reactor was employed to steam explode corn fiber at various degrees of severity to evaluate the potential of using this feedstock as part of an enzymatically mediated cellulose-to-ethanol process. Severity was controlled by altering temperature (150-230 degrees C), residence time (1-9 min), and SO2 concentration (0-6% [w/w] dry matter). The effects of varying the different parameters were assessed by response surface modeling.

SO2-catalyzed steam explosion of corn fiber for ethanol production.

Corn fiber, a by-product of the corn wet-milling industry, represents a renewable resource that is readily available in significant quantities and could potentially serve as a low-cost feedstock for the production of fuel-grade alcohol. In this study, we used a batch reactor to steam explode corn fiber at various degrees of severity to evaluate the potential of using this feedstock in the bioconversion process. The results indicated that maximum sugar yields (soluble and following enzymatic hydrolysis) were recovered from corn fiber that was pretreated at 190 degrees C for 5 min with 6% SO2.