12-03: Small-scale Enzymatic Conversion Screens to Assist in the Development of Improved Energy Crop Varieties

In the development of improved energy crop varieties, obtaining accurate chemical composition and conversion performance characteristics will be critical.  Ceres has previously developed small-scale conversion assays for the assessment of switchgrass biomass.  Here we display information on small laboratory-scale, high-throughput assays that can be used to assess the conversion efficiencies of Arabidopsis and sorghum.  Both acidic (APT) and basic (BPT) pretreatment methods have been employed.  Ceres has generated a collection of thousands of transgenic Arabidopsis lines, each overexpressing a single full length cDNA.  A selection of transgenic Arabidopsis lines bearing misexpressed genes relevant to cell wall biosynthesis have been grown to maturity and assessed for conversion efficiency.  Additionally, Ceres has available hundreds of genetically diverse sorghum samples, and the biomass collected from a subset of these lines has been assessed for relative digestibility in Ceres’ small-scale conversion assays.  For both plant species, lines with distinct differences in glucose released per gram dry biomass and/or in percent of theoretical maximum glucose yield have been identified.  In the case of the Arabidopsis lines, these conversion assays provide a direct means to identify genes that can influence conversion processing performance, leading to higher rates of conversion and higher final sugar yields.  The sorghum assays assist in the identification of sorghum lines with superior conversion characteristics.  This information will be invaluable to breeders and genetic engineers in the design of improved energy crop varieties that give higher conversion product yield per ton of biomass input to a conversion process.