The combination of acid and alkaline pretreatments (strong
acid-strong-alkali or weak acid–weak alkali) was effective in preparing
corncob for ethanol production when added at high concentration
to a SSF setup. Pretreatment removed most of the noncellulosic
materials, making cellulose more accessible to enzymes
that convert it into fermentable sugars. The density of the substrate,
but not its viscosity, increased after pretreatment, which allowed
SSF to be performed at high DM concentrations