Process optimization and performance evaluation on sequential ionic liquid dissolution-solid acid saccharification of sago waste

► Effective sequential ionic liquid dissolution-solid acid saccharification process. ► 98.3% reducing sugars yield was achieved under optimized conditions. ► The quadratic models developed are of good predictive accuracy. ► The process is of better yield compared to other saccharification schemes. ► It offers high reaction rate, ease products separation and catalyst reusability.