(261f) The Correlation Between Cellulose Allomorphs (I and II) and Conversion after Removal of Hemicellulose and Lignin of Lignocellulose

Yanliang Song, Xu Zhang, Tianwei Tan

Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China

H₂SO₄, NaOH and H₃PO₄ were applied to decompose three lignocellulose samples (giant reeds, pennisetum and corn stalks) to investigate the correlation between cellulose allomorphs (cellulose I and II) and conversion of cellulose. The effects of removal of hemicellulose and lignin on the surface morphology, crystallinity index (CrI), cellulose allomorphs (cellulose I and II) and enzymatic hydrolysis under different pretreatments were also studied. CrI of cellulose I (CrI-I) caused by concentrated H₃PO₄ pretreatment reached 11.19%, 24.93% and 8.15% for the three samples, respectively. Pretreatment methods had beneficial effects of different levels on enzymatic hydrolysis: NaOH-delignification > H₂SO₄-hydrolysis > H₃PO₄-depolymerization; as for three lignocellulose samples, the enzymatic hydrolysis of three samples followed the order of corn stalks > pennisetum > giant reeds after each treatment. Treated corn stalks showed highest conversion of cellulose among three samples, irrespective of the pretreatment applied. This accounted for the widely use of corn stalks as the renewable crop substrate to synthesize bioethanol. CrI of cellulose I (CrI-I) negatively affected cellulose conversion but CrI of cellulose II (CrI-II) positively affected cellulose conversion. It contributes to make the strategy to transform cellulose I to cellulose II and enhancing enzymatic hydrolysis of lignocellulose.