Location: Bioenergy Research
Project Number: 5010-41000-149-00-D
Project Type: In-House Appropriated
Start Date: Nov 27, 2009
End Date: Aug 28, 2014
Objective 1: Starting with industrial strains of yeast, develop new commercially-viable strains that have (1) improved inhibitor tolerance and (2) wide sugar-substrate specificity for fermenting lignocellulosic hydrolyzates to fuel ethanol. Objective 2: Develop (1) microbial based pretreatment and (2) simultaneous saccharification and fermentation (SSF) technologies that will enable commercially-viable processes for converting lignocellulosic feedstocks to fuel ethanol. Objective 3: Develop novel technologies that enable commercially-preferred processes for producing fuel-grade butanol from lignocellulosic feedstocks. Objective 4: Develop fermentative and enzymatic based technologies that will enable commercially-preferred processes for the production of xylitol from lignocellulose hydrolyzates.
The overall goal of this project is to develop commercially-targeted, integrated bioprocess technologies for production of biofuels and value-added coproducts from lignocellulosic feedstocks. The plan will emphasize microbiologically based approaches to overcome technical constraints that impede industrial applications. Our target is to use corn stover as a model lignocellulosic feedstock for ethanol, butanol, and xylitol production. This research will focus on screening for yeast (Saccharomyces) strains that can tolerate the fermentation inhibitors typically formed during certain pretreatments of lignocellulosic biomass and developing a recombinant S. cerevisiae strain that can efficiently ferment both glucose and xylose derived from lignocellulosic feedstocks. We will develop a microbial pretreatment at the laboratory scale and a simultaneous saccharification and fermentation (SSF) process for production of ethanol from a microbially pretreated feedstock using the recombinant S. cerevisiae strain developed in this project plan. We will identify and characterize the fermentation stimulating/enhancing chemicals present in dilute acid hydrolyzate of wheat straw and develop an integrated SSF with product recovery (SSFR) using ionic liquid or vacuum for efficient production of butanol which is very toxic to the fermentative bacterium. Finally, we will develop batch and fed-batch fermentation processes for production of xylitol from the hemicellulosic hydrolyzates of corn stover and a cell-free enzymatic method with cofactor regeneration for its production. This research project will greatly help to overcome the fermentation related challenges associated with the production of biofuels and coproducts from lignocellulosic feedstocks.