The role of glycoside hydrolases in reducing cell wall recalcitrance

The overall recalcitrance of lignocellulosic biomass to hydrothermal pretreatment and subsequent enzymatic deconstruction represents a significant cost barrier to the widespread development of biofuels technologies. To explore the possibility of reducing the recalcitrance of lignocellulosic biomass, we have generated a library of glycoside hydrolases across several families from a variety of sources, which we transformed into Arabidopsis thaliana with expression targeted to the cell wall under a constitutive promoter. Here we explore the possibility that in planta expression of specific glycoside hydrolase families will allow these enzymes to access their substrates during cell wall construction, rendering cellulose more amenable to pretreatment and enzyme digestion. The transgenic A. thaliana plants were healthy and developed normally compared with the wild type. After hydrothermal pretreatment and enzyme digestion, certain transformed plants were 10-15% more digestible than the wild type plants, suggesting that the expression of specific GH’s during cell wall construction altered the inherent recalcitrance of the cell wall.