Quantificação de açúcares redutores da casca de arroz após diferentes tipos de pré-tratamento seguido da hidrólise enzimática

Abstract

The production of ethanol from lignocellulosic materials is now an alternative in reducing the use of fossil fuels. The use of rice husk to produce ethanol can be a valuable option, being an agricultural residue abundantly available and, arising from the processing of rice. Several techniques have been studied aiming to the improvement and development of new technologies for ethanol production, based on the lignocellulosic material. This study aimed to quantify the sugars sample after the pre-treatment with acid and basic and hydrothermal pretreatment, followed by enzymatic hydrolysis. Samples of rice husk were treated with dilute sulfuric acid at a concentration of 5% (v/v), sodium hydroxide diluted to 0.25 M and hot water. Pretreatments were carried out in an autoclave at 1.1 atm, 121°C for 30 minutes. Subsequently the pre-treatment was performed enzymatic hydrolysis that used the cellulase enzyme as a catalyst of the reaction. The total reaction time of hydrolysis was 72 hours at 50°C. The results showed that pre-treatment followed by base hydrolysis enzymatic process that was released the largest number of glucose, resulting in a concentration of 1.99 g/L of glucose solution for the enzymatic activation time of 48 hours. Pretreatment acid showed the best glucose concentration 1.27 g/L after 24 hours of enzymatic action and hydrothermal pretreatment generated the highest concentration of glucose, 1.16 g/L after 12 h of enzymatic reaction.