Co-production of high-gravity bioethanol and succinic acid from potassium peroxymonosulfate and deacetylation sequentially pretreated sugarcane bagasse by simultaneous saccharification and co-fermentation

•A novel pretreatment process based on PMS and AD was established under mild condition.•The established process was efficient with high holocellulose recovery.•The pretreated SCB showed an excellent SSCF performance with high yield.•High titer of ethanol and succinic acid were co-produced at low enzyme loading. Pretreatment is a necessary step in the process of biorefinery of lignocellulosics. Here, a novel sequential sugarcane bagasse (SCB) pretreatment method was developed based on potassium peroxymonosulfate (PMS) and alkaline deacetylation (AD) under mild conditions. The co-pretreatment could efficiently remove the lignin and acetyl groups, resulting in a holocellulose-rich (83.5%) solid with superior degradability and a high overall recovery of holocellulose (81.2%). Meanwhile, the highest ethanol titer of 120.77 g/L and succinic acid production of 34.84 g/L were obtained by simultaneous saccharification and co-fermentation (SSCF) without the sterilization process for the pretreated SCB (equivalent to an ethanol yield of 0.36 g/g and a succinic acid yield of 0.10 g/g from the holocellulose in raw SCB). These results demonstrated that a high level of bioethanol and bio-based succinic acid can be achieved by the combination of the newly-developed SCB pretreatment method and the robust yeast strain.