Towards understanding structural changes of photoperiod-sensitive sorghum biomass during sulfuric acid pretreatment

► Wide-angle and small-angle X-ray scattering were used to study biomass structure. ► Both cellulose crystallinity and crystal size increased as the temperature increased. ► Simultaneous hydrolysis and crystallization of cellulose was found at 160 °C. ► The increase of microvoids volume contributes to the increased total surface area.