(461a) Hot Water and Dilute Acid Pretreatment of High and Low Specific Gravity Populus Deltoides Clones

Hybrid poplars, Populus sp. are hardwood feedstocks that grow as understory species in forest management areas that are logged for softwood. Because of the mixed cultures found in forested environments, this study involves sampling not only wood and bark from hybrid poplar, but also mixed cultures containing low and high specific gravity specimens. The objective of this research was to use hot water and dilute acid pretreatment to obtain extracts that contain high percentages of hemicellulose sugars. Dilute sulfuric acid (0.1%) or water was added to 7.5 g of wood and bark chips that were ground to a particle size of approximately 4 mm. These samples were placed into thick-walled stainless steel tubes and placed into a fluidized sand bath at temperatures between 130-240 °C and run for 20-100 min. Filtered solutions from the sulfuric acid treatment were neutralized with calcium carbonate. Extracts from both dilute acid and water treatments were filtered with 0.2 μm syringe filter and analyzed by HPLC, using either a carbohydrate method or an organic acid method. Results from this study suggest that hot water and dilute acid pretreatments can help in optimizing the extraction of hemicellulose sugars from hybrid poplar bark and wood.