Enhancing fermentable sugar yield from cassava pulp for bioethanol production: microwave-coupled enzymatic hydrolysis approach

Cassava pulp, a potential biological feedstock for ethanol production has been subjected to microwave-assisted alkali pretreatment and microwave-coupled enzymatic hydrolysis. Microwave pretreatment may be a good alternative as it can reduce the pretreatment time and improve the enzymatic activity during hydrolysis. Liquid to solid ratio for the pretreatment of cassava pulp was found to be 20:1. Cassava pulp was pretreated at various NaOH concentration, microwave temperature and gave maximum yield of reducing sugar with 1.5 % NaOH at 90 A degrees C in 30 min than conventional alkali pretreatment after enzymatic hydrolysis. The subsequent enzymatic saccharification of pretreated cassava pulp using alpha amylase dosage of 400 IU at microwave temperature of 90 A degrees C resulted in highest reducing sugar yield of 723 mg/g pulp. Microwave-assisted alkali pretreatment improved the enzymatic saccharification of cassava pulp by increasing its accessibility to hydrolytic enzymes. Microwave-assisted alkali pretreatment and microwave-coupled enzymatic hydrolysis are found to be efficient for improving the yield of reducing sugar.