The impact of particle size and initial solid loading.pdf

ORIGINAL PAPER The impact of particle size and initial solid loading on thermochemical pretreatment of wheat straw for improving sugar recovery Oscar A. Rojas-Rejo?n ? Arturo Sa?nchez Received: 30 April 2013 / Accepted: 15 December 2013 / Published online: 4 January 2014  Springer-Verlag Berlin Heidelberg 2013 Abstract This work studies the effect of initial solid load (4–32 %; w/v, DS) and particle size (0.41–50 mm) on monosaccharide yield of wheat straw subjected to dilute H2SO4 (0.75 %, v/v) pretreatment and enzymatic sac- charification. Response surface methodology (RSM) based on a full factorial design (FFD) was used for the statistical analysis of pretreatment and enzymatic hydrolysis. The highest xylose yield obtained during pretreatment (ca. 86 %; of theoretical) was achieved at 4 % (w/v, DS) and 25 mm. The solid fraction obtained from the first set of experiments was subjected to enzymatic hydrolysis at constant enzyme dosage (17 FPU/g); statistical analysis revealed that glucose yield was favored with solids pre- treated at low initial solid loads and small particle sizes. Dynamic experiments showed that glucose yield did not increase after 48 h of enzymatic hydrolysis. Once estab- lished pretreatment conditions, experiments were carried out with several initial solid loading (4–24 %; w/v, DS) and enzyme dosages (5–50 FPU/g). Two straw sizes (0.41 and 50 mm) were used for verification purposes. The highest glucose yield (ca. 55 %; of theoretical) was achieved at 4 % (w/v, DS), 0.41 mm and 50 FPU/g. Sta- tistical analysis of experiments showed that at low enzyme dosage, particle size had a remarkable effect over glucose yield and initial solid load was the main factor for glucose yield. Keywords Thermochemical pretreatment  Wheat straw  Enzymatic saccharification  Cellulosic ethanol Introduction Lignocellulosic biomass represents the largest source of materials currently available for production of alternative biofuels and high value-added bioproducts.