Plant Cell Wall Groove Structure Observation And Its Potential Function Analysis

As second generation of bioenergy, lignocellulosic ethanol has been considered for partial replacement of fossil energy and environmental care in China and over the world. However, lignocellulose recalcitrance determines an unacceptably costly biomass process. As recalcitrance is affected by plant cell wall composition and wall polymer features, it becomes essential to find out the fundamental plant cell wall structure that determines biomass enzymatic saccharification.In this study, I initially established sequential wall polymer extraction technology to observe plant cell wall fundamental structure using atomic force microscopy(AFM) in Miscanthus and rice samples. Then, I observed a ―groove-like‖ structure on the lignocellulose surface and discussed its potential role in biomass enzymatic hydrolysis under various pretreatments. The main results are described below:1. The optimal condition for AFM observation of lignocelluloses surface structure: the crude cellulose was treated with CBHI enzyme and 1, 4-dioxane treatment, and then extracted with 2M Na OH for 2 hours under 85℃. The ―groove‖ structures were observed in Miscanthus, rice, wheat and maize.2. Comparative analysis indicated that the Miscanthus and rice samples with relatively high biomass digestibility exhibited more ditches, suggesting the model that the groove structures were the accession places of cellulases for initiating lignocellulose enzymatic digestion.3. Correlation analysis was performed using rice cell walls mutants, suggesting that Os GH9 genes may involve in the ―groove‖ structure formation.