USDA-DOE Plant Feedstock Genomics for Bioenergy Awardee Meeting

and the Joint BioEnergy Institute (JBEI) are collaborating to understand how biomass pretreatments with much different deconstruction patterns impact the chemical and ultrastructural features of biomass and its biological conversion to sugars. Dilute sulfuric acid (DA), ammonia fiber expansion (AFEX), and ionic liquid (IL) pretreatments are applied to the same source of corn stover by the BESC, GLBRC, and JBEI, respectively. Common sources of cellulase and other accessory enzymes are then employed to release sugars from the solids left after each pretreatment. The GLBRC applies material balances to each overall pretreatment-hydrolysis system to determine the fates of key biomass constituents and also optimizes enzyme formulations for each substrate using their microplate saccharification system. The BESC focuses on characterizing how cellulose accessibility to enzymes, enzyme adsorption and desorption kinetics, and changes in substrate features during hydrolysis vary for the solids resulting from the three pretreatments over the course of enzymatic hydrolysis, especially at low enzyme loadings that are commercially promising. ultrastructural and chemical changes resulting from each pretreatment. These results will then be integrated to identify key features influencing enzymatic hydrolysis of solids from these pretreatments and similarities and differences in their impacts on the effectiveness of enzymatic hydrolysis of biomass. the project described below. BESC research is multidisciplinary by design and multi-institutional in composition. Plant cell walls with higher cellulose/lower lignin levels, increased wall thickness and increased cell number constitute some desirable characteristics of feedstock materials for biochemical ethanol production. Understanding the underlying molecular, biochemical and phenotypic properties of the cell wall is critical to enabling the design of suitably tailored feedstocks. Tension wood formed in response to tension stress on the outer side of the bent stem of a woody angiosperm is characterized by these desirable feedstock properties. Here we present results from an integrated study of tension stress response in Populus stems. Xylem and phloem samples were collected from two genotypes of Populus following a 14-day bending stress treatment. For molecular studies, Illumina-based transcriptome profiling, targeted qRT-PCR and LC-MS/MS-based proteome profiling was performed in triplicate runs. For phenotypic characterization , MBMS cell wall compositional analysis, SEM and CARS imaging, and 13 C cross-polarization magic angle spinning (CP/MAS) NMR, gel permeation chromatography (GPC) were used to characterize the ultrastructure of cellulose, microstructure of wood and the chemical profiles of lignin and cellulose. MBMS revealed that the tension wood samples have higher cellulose and lower lignin levels. This was correlated …