title: Optimization of Hydrothermal and Diluted Acid Pretreatments of TunisianLuffa cylindrica(L.) Fibers for 2G Bioethanol Production through the Cubic Central Composite Experimental Design CCD: Response Surface Methodology.
abstract: This paper opens up a new issue dealing withLuffa cylindrica(LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely,α-cellulose (45.80%  ± 1.3), hemicelluloses (20.76%  ± 0.3), and lignins (13.15%  ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled withSaccharomyces cerevisiae. LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia.
authors.forename: Kaouther
authors.identifier: 0000-0002-3213-6696
authors.initials: K
authors.lastname: Zaafouri
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia; Department of Biotechnology and Environment Sciences, High Institute of Environmental Science and Technology (HIEST) of Borj-Cedria, Borj-Cedria Technopark, BP 1003, 2050 Hammam-Lif, Tunisia.
authors.forename: Manel
authors.initials: M
authors.lastname: Ziadi
authors.affiliation: Laboratory of Wind Energy Control and Waste Energy Recovery (LMEEVED), Research and Technology Center of Energy (CRTEn), Borj-Cedria Technopark, BP 95, 2050 Hammam-Lif, Tunisia.
authors.forename: Aida
authors.initials: A
authors.lastname: Ben Hassen-Trabelsi
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia; Department of Biotechnology and Environment Sciences, High Institute of Environmental Science and Technology (HIEST) of Borj-Cedria, Borj-Cedria Technopark, BP 1003, 2050 Hammam-Lif, Tunisia.
authors.forename: Sabrine
authors.initials: S
authors.lastname: Mekni
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia; Department of Biotechnology and Environment Sciences, High Institute of Environmental Science and Technology (HIEST) of Borj-Cedria, Borj-Cedria Technopark, BP 1003, 2050 Hammam-Lif, Tunisia.
authors.forename: Balkiss
authors.initials: B
authors.lastname: Aïssi
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia; Laboratory of Wind Energy Control and Waste Energy Recovery (LMEEVED), Research and Technology Center of Energy (CRTEn), Borj-Cedria Technopark, BP 95, 2050 Hammam-Lif, Tunisia.
authors.forename: Marwen
authors.initials: M
authors.lastname: Alaya
authors.affiliation: Laboratory of Materials Chemistry and Catalysis, Faculty of Sciences of Tunis, El Manar University, Tunis, Tunisia.
authors.forename: Latifa
authors.initials: L
authors.lastname: Bergaoui
authors.affiliation: Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia.
authors.forename: Moktar
authors.initials: M
authors.lastname: Hamdi
mesh_terms: D056804:Biofuels; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D057168:Distillation; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D029776:Luffa / Q000187:drug effects*; D012044:Regression Analysis; D017550:Spectroscopy, Fourier Transform Infrared; D013464:Sulfuric Acids / Q000494:pharmacology*; D013696:Temperature; D013818:Thermogravimetry; D014867:Water / Q000494:pharmacology*
chemical_list: D056804:Biofuels; D013464:Sulfuric Acids; D014867:Water; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; C033158:sulfuric acid