(545f) Performance of Pilot Scale Dilute Acid Pretreatment and Enzymatic Hydrolysis of Pine Sawdust for Production of Fermentable Sugars.

The pilot scale continuous processes for dilute acid pretreatment of lignocellulosic biomass have been limited. This study investigates the performance of continuous pilot scale dilute acid pretreatment of pine sawdust, followed by enzymatic hydrolysis to produce fermentable sugars. The pretreatment of pine sawdust with a moisture content of 20 wt% was conducted at 160°C, 15–20 minutes of residence time, 1.5 wt% sulfuric acid. The process was carried out in a pilot-scale facility with a capacity of 1 ton of pine sawdust per day. The pretreated solids were subjected to two washing methods (water and sodium citrate buffer) to evaluate their effects on enzymatic hydrolysis. Preliminary enzymatic hydrolysis of buffer and water washed pretreated solids was performed at the bench scale using two different enzyme formulations and a variable multi-step addition approach. Enzyme loading applications were varied to determine a dosage regime maximizing saccharification efficiency via periodic enzyme addition. Preliminary results indicate that sodium citrate buffer washing improves pH stability and increases sugar yields compared to water washing. The bench scale enzymatic hydrolysis of preconditioned solids indicate that the saccharification efficiency of higher than 50% can be attained in 24 hours with buffer washed solids. At the pilot scale, prior to enzymatic hydrolysis the pretreated solids are washed with sodium citrate buffer with a pH of 4.6. The buffer washed solids are mixed with fresh water at a solid consistency of 5 wt (on a dry basis) in a jacketed stirred reactor with a capacity of 1800 Liters. The temperature of the enzymatic hydrolysis is maintained at 45 to 50 °C using low pressure steam. After the addition of enzymes to the jacketed reactor, the samples were periodically collected for 48 to 72 hours to determine the C5 and C6 monomeric sugar concentration using the HPLC. This research provides a foundation for further pilot-scale studies, aiming to enhance the feasibility of bio-based sugar production for industrial applications.