PRE-TREATMENT AND ENZYMATIC SACRIFICATION OF RICE HUSK

Abstract

The present study evaluated the hydrolysis of rice husk, by means of alkaline peroxide, acid peroxide and silicate peroxide pretreatment, followed by enzymatic hydrolysis using cellulases, with a high level of β-glucosidases and hemicellulases. Pretreatments were performed by varying the concentrations of the alkaline medium (0, 2, 4 and 6 % p/v), acid (0, 5, 10 and 15 % v/v) and silicates (0, 5, 10 and 15 % v/v) in varying concentrations of peroxide (0, 5, 10 and 15 % v/v). Enzymatic hydrolysis was performed at 50 °C, pH 5, 72 h, 0.3 mL of enzyme per g of husk, with a load of 5 % w/v. The morphological characterization of the surface of the rice husk by means of the SEM presented a greater transformation in alkaline-peroxide medium. The concentration of reducing sugars after the alkaline peroxide pretreatment (6 % KOH – 15 % H2 O2 , pH 11, 70 °C, 3 h and with a load 10 % p/v) and the enzymatic hydrolysis (50 °C, pH 5, 72 h, 0.3 mL/g, with a load of 5% w/v) reached a saccharification of up to 73.2 %. The released reducing sugars could be fermented in the process of obtaining 2G ethanol.