title: Cogon grass (Imperata cylindrica), a potential biomass candidate for bioethanol: cell wall structural changes enhancing hydrolysis in a mild alkali pretreatment regime.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Applied Life Science (BK21 Program), Gyeongsang National University, Chinju 660-701, Republic of Korea.|Dept of Food Science, Gyeongnam National University of Science and Technology, Jinju 660-758, Republic of Korea.
authors.forename: Md Azizul
authors.initials: MA
authors.lastname: Haque
authors.affiliation: Division of Applied Life Science (BK21 Program), Gyeongsang National University, Chinju 660-701, Republic of Korea.
authors.forename: Dhirendra Nath
authors.initials: DN
authors.lastname: Barman
authors.affiliation: Gyeongsangnam-do Agricultural Research and Extension Service, Jinju 660-758, Republic of Korea.
authors.forename: Min Keun
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Division of Applied Life Science (BK21 Program), Gyeongsang National University, Chinju 660-701, Republic of Korea.|Research Institute of Agriculture and Life Science, Gyeongsang National University, Chinju, 660-701, Republic of Korea.
authors.forename: Han Dae
authors.initials: HD
authors.lastname: Yun
authors.affiliation: Dept of Food Science, Gyeongnam National University of Science and Technology, Jinju 660-758, Republic of Korea.
authors.forename: Kye Man
authors.initials: KM
authors.lastname: Cho
mesh_terms: D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D000431:Ethanol / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006109:Poaceae / Q000166:cytology*; D012972:Sodium Hydroxide / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D056804:Biofuels; D000431:Ethanol; D012972:Sodium Hydroxide
keywords: cogon grass; mild alkali pretreatment; saccharification; structural features