(714e) Effect of Steam Explosion On Degradability and Accessiblity of Loblolly Pine In Bioethanol Applications

Among the various biomass pretreatment methods, steam explosion is one of the most widely used due to its cost-effective disruption of the plant structure and hence enhanced enzymatic accessibility. The operational parameters including temperature, residence time and acid concentration have pronounced effect on crystallinity (CrI) of the feedstock loblolly pine. CrI was determined from X-ray diffraction pattern with the method of least squares and it was found to decrease as pretreatment severity increase.

Three different substrates, Avicel, phosphoric acid swollen cellulose (PASC), and SO₂ steam exploded Loblolly pine (SELP), were subjected to enzymatic hydrolysis and subsequent adsorption study. Both SELP samples (2.9-419-5 and 5-417-5) were found more readily degraded by the CelluclastÒ enzyme system than Avicel. Despite the complexity of both substrates and enzyme mixtures, the SELP adsorption isotherm can be fitted to a Langmuir isotherm with R² > 0.99. The saturation point was reached at ~6.24 mg/ml total enzyme loading. Adsorption data was correlated with initial rates and a linear relationship between initial rate and adsorption amount was confirmed.