Start Date: Sep 01, 2004
End Date: Jul 19, 2009
The overall goal is to produce biofuel from waste lignocellulosic agricultural residues and processing byproducts at a price competitive with corn starch-based fermentation process. Specific approaches have the following components: 1. Developing an effective pretreatment strategy that will greatly increase the efficiency of enzymatic hydrolysis of lignocellulose. For this, various pretreatment options will be evaluated. Dilute acid pretreatment at high temperature generates furfural, hydroxymethyl furfural, levulinic acid, and unknown aromatic compounds which are inhibitory to fermentative microorganisms. Chemical and biological methods will be explored to detoxify these hydrolyzates. Mechanisms of such detoxification will be studied. 2. Developing high productivity fermentation system for production of biofuels (ethanol, butanol) from lignocellulosic hydrolyzates. For this, batch and continuous fermentations with cell recycle will be studied. Tolerance of the fermentative microorganism to high substrate, fermentation inhibitors, organic acids, and alcohols will be studied with an aim to identify robust organisms. 3. Pervaporation, gas stripping, and liquid-liquid extraction as well as conventional distillation methods will be investigated to economically recover biofuels from dilute fermentation broths. 4. In order to be economic, the steps involved in any bioconversion process need to be integrated. Research will be conducted to integrate enzymatic saccharification, fermentation, and downstream processing technologies for production of biofuels. The technologies for both ethanol and butanol production will be demonstrated at 100-L scale, and a preliminary cost analysis for each process will be performed. BSL-1 and Risk Group RG1 recertified April 17, 2008.