Bioconversion of sawdust into ethanol using dilute sulfuric acid-assisted continuous twin screw-driven reactor pretreatment and fed-batch simultaneous saccharification and fermentation

► Acid-assisted CTSR pretreatment enhances sawdust digestibility. ► Optimal operating conditions of CTSR pretreatment were estimated. ► Timing of enzyme and solid addition in fed-batch SSF were investigated. ► Ethanol titer in three stage fed-batch SSF of pretreated sawdust almost reached a 4%.