Correlating cell wall properties diverse grasses to their response to alkaline pretreatment and enzymatic hydrolysis

In the U.S., grasses including agricultural residues such as corn stover and dedicated bioenergy feedstocks such as switchgrass are expected to be important future feedstocks for cellulosic ethanol processes.  Identifying “high digestibility” phenotypes in grasses and understanding compositional and structural contributions the cell wall’s responsiveness to pretreatment and hydrolysis are important in the breeding or engineering of plants that are less recalcitrant.  In this study, a panel of 30 diverse maize lines as well as other diverse grasses representing a wide spectrum of relative recalcitrance are subjected to hydrolysis either prior to and following a mild NaOH pretreatment.  A number of properties are characterized including structural polysaccharide and lignin contents, ferulic and p-coumaric acid contents, and water retention value (WRV) and the relative contributions of these properties to the hydrolysis yields is determined. Additionally, high-throughput analysis techniques including pyrolysis molecular beam mass spectrometry (py-MBMS) and near-infrared spectroscopy (NIR) are utilized in combination with chemometric models to both predict the cell wall properties including lignin content, p-coumaric and ferulic acids content, and  hydrolysis yields.