Effect of Alkaline Pretreatment Parameters on Saccharification of Waste Pea Hulls

Pea is a widely adapted crop and can be grown in every temperature region. In India pea is cultivated in Uttar Pradesh, Madhya Pradesh, Himachal Pradesh, Punjab, Haryana, Rajasthan, Maharashtra, Bihar and Karnataka with total production of 3029 metric tons. During industrial processing, large quantities of hulls are obtained as a waste product from the dehulling process. This study focused on converting the pea hulls into fermentable sugars by dilute alkaline pretreatment. Raw pea hulls are composed of 82.30% total dietary fiber, 62.3% cellulose, 8.2% hemicelluloses and 1.7% ash. Box-Behnken design was used and statistically designed experiments were conducted to study the effect of hydrogen peroxide concentration (4, 7.5 and 11%), temperature (25, 30 and 35 °C) and incubation time (18, 24 and 30 h) on the sugar release of pea hulls after alkaline pretreatment. The results showed an increase in acid concentration and reaction temperature gave high sugar yield in the liquid fraction. However, an increase in reaction time resulted in degradation of sugar into residue. A quadratic model for sugar yield was formulated based on the experimental results. Maximum sugar release was found to be 2.87 mg/ml after treatment with 9% H₂O₂ concentration at 27 °C temperature and 18 hours of treatment.