Evaluation of the Addition of Polyethylene Glycol in the Enzymatic Hydrolysis of Rice Husk

This study evaluated the effect of polyethylene glycol (PEG 1500 and 4000) addition on the enzymatic hydrolysis (EH) of ground rice husk (≤250 μm). To reduce the amount of enzyme adsorbed on silicon dioxide and lignin and to evaluate the enzymatic hydrolysis, PEG 1500 and 4000 g/mol were added at three concentrations (0.3, 0.4 and 0.5 g PEG/g SiO2). When PEG 1500 was added at 0.5 g/g SiO2, the conversion of cellulose to cellobiose was not significantly increased (p ≥ 0.05); the conversion to glucose was 41.76%, and the conversion of hemicellulose to xylose was 93.45%, all with respect to the control assay. Addition of PEG 4000 at 0.5 g/g SiO2 showed an increase of 14.78% in the hydrolysis of cellulose to cellobiose, 56.59% in that of cellulose to glucose, and 93.24% in that of hemicellulose to xylose. The addition of PEG shows that at a higher molecular weight and higher concentration, there are significant differences in the percentage of conversion of cellulose and hemicellulose into fermentable sugars, achieving efficiencies of ≈75%.