Removal of glucuronic acid from xylan is a strategy to improve the conversion of plant biomass to sugars for bioenergy

• DOI: 10.1186/s13068-017-0902-1
• Publication Date: 2017-09-19T15:09:06Z
• Authors: Jan J. Lyczakowski; Krzysztof B. Wicher; Oliver M. Terrett; Nuno Faria-Blanc; Xiaolan Yu; David Brown; Kristian B. R. M....; Paul Dupree; Marta Busse-Wicher
• Keywords: Softwood; Hemicellulose; Lignocellulosic Biomass

Plant lignocellulosic biomass can be a source of fermentable sugars for the production second generation biofuels and biochemicals. The recalcitrance this plant material is one major obstacles in its conversion into sugars. Biomass primarily composed secondary cell walls, which made cellulose, hemicelluloses lignin. Xylan, hemicellulose, binds to cellulose microfibril hypothesised form an interface between lignin cellulose. Both softwood hardwood xylan carry glucuronic acid side branches. As branching may important abundant, non-food competing, it investigate how conifer synthesised. Here, we show using Arabidopsis gux mutant that removal glucuronosyl substitutions allow 30% more glucose over 700% xylose released during saccharification. Ethanol yields obtained through enzymatic saccharification fermentation were double those non-mutant material. Our analysis additional mutants demonstrates absence GlcA unique conferring reduced phenotype. hardwoods, branched with GlcA. We use transcriptomic identify enzymes might responsible addition branches onto industrially softwood. Using combination vitro vivo activity assays, demonstrate white spruce (Picea glauca) gene, PgGUX, encodes active transferase. Glucuronic introduced by PgGUX reduces sugar release wild-type levels indicating fulfil same biological function as native glucuronosylation. Removal from results largest increase plants grow size. Additionally, used work did not undergo any chemical pretreatment, thus increased monosaccharide achieved without environmentally hazardous pretreatment procedures. Therefore, identification gymnosperm enzyme, likely glucuronosylation, provides mutagenesis target genetically improved forestry trees.