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Cogon grass ( Imperata cylindrica ), a potential biomass candidate for bioethanol: cell wall structural changes enhancing hydrolysis in a mild alkali pretreatment regime
Author(s) -
Haque Md Azizul,
Barman Dhirendra Nath,
Kim Min Keun,
Yun Han Dae,
Cho Kye Man
Publication year - 2015
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.7288
Subject(s) - imperata , cellulose , lignin , chemistry , hydrolysis , biomass (ecology) , fourier transform infrared spectroscopy , nuclear chemistry , biofuel , enzymatic hydrolysis , sugar , alkali metal , pulp and paper industry , food science , chemical engineering , botany , organic chemistry , agronomy , microbiology and biotechnology , biology , engineering
BACKGROUND Imperata cylindrica is being considered as a biomass candidate for bioethanol. This work aimed to evaluate a mild alkali pretreatment effect on the Imperata recalcitrant structure. Therefore, varied concentrations of NaOH (0, 7.5, 15, 20, and 25 g L −1 ) were applied as treatments to Imperata at 105 °C for 10 min. RESULTS Scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy studies revealed that 20 to 25 g L −1 NaOH ‐treated Imperata exposed amorphous cellulose on surface granules composed of lignin, waxes, and partly hemicelluloses were abolished due to the comprehensive disruption of the linkages between lignin and carbohydrates. The cellulose crystalline index was increased with 7.5 to 20 g L −1 NaOH treatments and reduced with a 25 g L −1 NaOH treatment. In fact, the cellulose content in solids increased with the increasing NaOH concentration and was estimated to be 720 and 740 g kg −1 for the 20 and 25 g L −1 NaOH treatments, respectively. The yield of the reducing sugar was obtained 805 and 813 mg g −1 from 20 and 25 g L −1 NaOH ‐treated Imperata , respectively. CONCLUSION Considering the cost of pretreatment, the 20 g L −1 NaOH treatment is judged to be effective for disrupting Imperata recalcitrance in this pretreatment regime. © 2015 Society of Chemical Industry