Effects of Particle Size on Biomass Pretreatment for Biofuel Production

Abstract

Biofuel production needs to be more efficient than its current status to increase its competitiveness. The multistep biofuel production is consisted of processes on biomass preprocessing and bioconversion stages. As a crucial parameter, biomass particle size has significant effects on both stages. It is essential to have an insightful understanding of the effects of particle size on sugar yield. Although numerous studies have been performed to meet this objective, there is no commonly accepted guideline on how to select particle size. One possible reason for this gap is the effects of particle size vary when different biomass pretreatment methods are employed. In this study, an assessment on the relationship between particle size and sugar yield was performed for four pretreatment methods. Three particle sizes (1, 4, and 8 mm) of corn stover and switchgrass biomass were used in supercritical CO2, dilute acid (H2SO4), dilute alkaline (Na2CO3), and metal oxide (MgO) pretreatments. Biomass compositional analyses were conducted before and after each pretreatment. Pretreatment solid recovery and sugar recovery rates were calculated. Enzymatic hydrolysis sugar yield and efficiency were used to evaluate the performance of hydrolysis and total sugar yield was used to interpret how much sugar a unit dry weight of biomass (before pretreatment) can yield through pretreatment and enzymatic hydrolysis combined. It was found that particle size was a weak indicator of enzymatic hydrolysis efficiency. There was little value in reducing particle size below 8 mm in order to overcome the resistance imposed by biomass structure on cellulose and xylan hydrolysis.

Deconstruction of Woody Biomass via Protic and Aprotic Ionic Liquid Pretreatment for Ethanol Production

“…It is commonly known that biomass particle size can substantially affect the efficiency of pretreatment and subsequent enzymatic hydrolysis. Particle size reduction enhances the effective surface area-to-volume ratio, facilitating enzyme accessibility into their substrates within the feedstocks. , Figure S6A shows the glucose and xylose yields from the enzymatic hydrolysis of [Ch]­[Lys]-pretreated biomass at 50 μm, 160 °C, and 3 h, using 30 mg of enzyme protein/g of starting biomass at a ratio of 9/1 Ctec3/HTec3. There was a significant increase in the average sugar yield for pine (43.4% of dry biomass) and fir (44.4% of dry biomass), which accounts for an increase of 62% for pine and 48% for fir compared to results at 2 mm particle size.…”