a b s t r a c t
Sweet sorghum has been regarded as a typical species for rich soluble-sugar and high lignocellulose
residues, but their effects on biomass digestibility remain unclear. In this study, we examined total 63
representative sweet sorghum accessions that displayed a varied sugar level at stalk and diverse cell wall
composition at bagasse. Correlative analysis showed that both soluble-sugar and dry-bagasse could not
significantly affect lignocellulose saccharification under chemical pretreatments. Comparative analyses of
five typical pairs of samples indicated that DP of crystalline cellulose and arabinose substitution degree of
non-KOH-extractable hemicelluloses distinctively affected lignocellulose crystallinity for high biomass
digestibility. By comparison, lignin could not alter lignocellulose crystallinity, but the KOH-extractable
G-monomer predominately determined lignin negative impacts on biomass digestions, and the G-levels
released from pretreatments significantly inhibited yeast fermentation. The results also suggested potential
genetic approaches for enhancing soluble-sugar level and lignocellulose digestibility and reducing
ethanol conversion inhibition in sweet sorghum.