Ultrastructural Changes to Overcome the Biomass Recalcitrance with Liquild Hot Water Pretreatment

Abstract

Energy sorghums and Pennisetum hybrids were pretreated with liquid hot water to investigate their recalcitrance to hydrothermal condition and cellulosic enzyme. The results about enzymatic hydrolysis of sorghum indicated that lignin level was an important restraining factor in the cellulosic digestibility, but was not the unique one. Moreover, although two Pennisetum hybrids had a great difference on the degree of polymerization of lignin and cellulose, there seemed no significant differences in terms of 72 h enzymatic digestibility. In addition, the degree of hemicellulose branching and lignin content might be the direct influencing factor on the size distribution of xylose oligomers released. And liquid hot water pretreatment can overcome biomass recalcitrance to enhance the enzymatic digestibility of cellulose based on the changes of ultrastructure on the surface of substrate.