Location: Bioenergy Research
Project Number: 5010-41000-161-000-D
Project Type: In-House Appropriated
Start Date: Aug 9, 2014
End Date: Jul 24, 2019
Objective:
Objective 1: In collaboration with ARS plant production laboratories, identify agronomic practices that maximize the value to biorefiners of lignocellulosic feedstocks.
Objective 2: Develop commercially-viable technologies to improve the commercial production of fermentable sugars from arabinoxylan in lignocellulosic biomass. Sub-objective 2.A. Identification and subsequent characterization of glycosidic bonds that occur singly or in patterns that are unrecognized by arabinoxylan carbohydrases. Sub-objective 2.B. Characterize kinetic variation of soluble xylan products released from hydrothermal and acid catalyzed pretreatments. Sub-objective 2.C. Identify key and highly active enzymes for the hydrolysis of natural substrates that compose ß-xylan: a-L-arabinofuranosidases acting on arabinoxylan, a-glucuronidases acting on uronoxylan, and ß-xylosidases acting on oligoxylans.
Objective 3: Develop technologies to manage hydrolyzate inhibitors in commercial-scale second generation biorefineries, including biorefineries utilizing significant water recycling. Sub-objective 3.A. Investigate multiple paths to engineering furan aldehyde tolerance in Saccharomyces cerevisiae for purpose of developing a platform biocatalyst. Sub-objective 3.B. Use biological inhibitor abatement to facilitate water recycling in conversion of biomass lignocellulose hydrolyzates.
Approach:
Goal 1. Demonstrate that agronomic decisions directly affect biomass conversion yields to sugars and biofuels by changes in cell wall structure and composition.
Goal 2.A. Show that plant cell wall xylan contains conserved glycosidic linkages across candidate biomass sources that are not hydrolyzed by commercially available enzymes.
Goal 2.B. Establish that bimodal kinetic hydrolysis of xylan release, frequently observed for acidic and hydrothermal treatments is a result of compositional variation within the xylan structure.
Goal 2.C. Discover key and highly active accessory enzymes for hydrolysis of heteroxylans by using activity on native substrates as a guide.
Hypothesis 3.A. Application of multiple molecular methods, including increased expression of transcriptional regulators and engineering of a catabolic pathway, will yield yeast strains with increased tolerance to furan inhibitors.
Goal 3.B. Determine the ability of an inhibitor-tolerant fungal strain that metabolizes fermentation inhibitors to facilitate reuse of process water streams.
