Pre-treatments applied to rice husk enzymatic hydrolysis: effect on structure, lignocellulosic components, and glucose production kinetics

Abstract

Freezing (-20 °C, 12h) and alkaline (NaOH 8%) pretreatments were applied individually and combined in rice husk (Oryza sativa L.) before their hydrolysis with cellulase (EC: 3.2.1.4.). The effects on structural modifications, lignin content, cellulose, hemicellulose content and glucose production were evaluated. In addition, the glucose production kinetics were described by using the Peleg model. The homogenous rice husk (1 g) with and without pretreatments was hydrolysed with 150 U of Cellulase in 10 ml of acetate for 60 h (37 °C, pH 5.5, 100 rpm). As results, the SEM images evidenced porous microstructures with less agglomeration generated by all pre-treatments, which were intensified by the combined pretreatment. This pre-treatment allowed to obtain higher cellulose (62.51 ± 0.3 %) content. Besides, the glucose content after pretreatments increased. The Peleg model parameters from glucose production kinetics during enzymatic hydrolysis were related to initial glucose content (G0), glucose production rate (1/k1) and maximum glucose yield (1/k2). After enzymatic hydrolysis process, compared to control glucose yield (0.359 ± 0.002 g G/g rice husk), this was 27%, 71% and 88% higher for freezing, alkaline and combined pre-treatments respectively.

Renewable Carbohydrates: Advancements in Sustainable Glucose Production and Optimization

“…Both rice husk and sugarcane bagasse have their unique characteristics, and the choice of feedstock would depend on the specific circumstances and objectives of the glucose production process. Production of glucose from rice husk will also follow the same process steps listed under sugarcane bagasse utilization, beginning with pretreatment (Aredo et al, 2020;Bohn et al, 2021;Cheoh, 2018). The same author also adopts a unique model called the Peleg kinetic model to determine the reaction rate constant.…”