Ibrahim Nasser Ahmed, Shella Permatasari Santoso, Phuong Lan Tran-Nguyen, Lien Huong Huynh, Suryadi Ismadji, Yi-Hsu Ju
The effects of subcritical water (SCW) and dilute acid pretreatments on the shedding bark of Melaleuca leucadendron (paper bark tree, PBT) biomass morphology, crystallinity index (CrI) and enzymatic saccharification were studied. The morphology of PBT bark was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. SCW pretreatment mainly extracted amorphous parts of the biomass hence its CrI increased, partial decrystallization of cellulose and exposing of intact nanofibers of cellulose were observed for SCW pretreatment at 180. °C. On the other hand, dilute acid pretreatment at 160. °C exhibited a large decrease in CrI, an increase in surface area, a decrease in lignin content and decrystallization of cellulose as well as the peel-off and degradation of some nanofiber bundles. Dilute acid and SCW pretreatments of PBT biomass resulted in about 4.5 fold enhancement in glucose release relative to the untreated one. © 2013 Elsevier Ltd.
Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106-07, 43 Keelung Rd., Sec. 4, Taiwan; Department of Chemical Engineering, Can Tho University, Can Tho City, 3-2 Street, Viet Nam; Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Surabaya 60114, Kalijudan 37, Indonesia