title: Second generation bioethanol production from Saccharum spontaneum L. ssp. aegyptiacum (Willd.) Hack.
abstract: Saccharum (Saccharum spontaneum L. ssp. aegyptiacum (Willd.) Hack.), is a rapidly growing, wide ranging high-yield perennial, suitable for second generation bioethanol production. This study evaluated oxalic acid as a pretreatment for bioconversion. Overall sugar yields, sugar degradation products, enzymatic glucan hydrolysis and ethanol production were studied as effects of temperature (150-190 degrees C), reaction time (10-40 min) and oxalic acid concentration 2-8% (w/w). Time and temperature were combined into a single parameter, Severity Factor (SF) [Log(R(0))], and related to oxalic acid using a response surface methodology. Maximum total sugar yield was attained at a SF of 2.93 and 6.79% (w/w) oxalic acid, while maximum formation of sugar degradation products was observed at the highest SF (4.05) and 5% (w/w) oxalic acid. These were also the conditions for maximum simultaneous saccharification and fermentation (SSF) of the residual solids. Commercial cellulases and Saccharomyces cerevisiae attained 89.9% glucan conversion and 17.8 g/l ethanol. Pichia stipitis CBS 6054 fermented hemicellulosic hydrolysates from less severe conditions to ethanol with a yield of 0.35 (g(e)/g(s)). Maximal product yields were 69% of theoretical value and 90% of the SSF conversion efficiency for hydrolysate fermentation and SSF, respectively.
authors.affiliation: Dipartimento di Scienze Agronomiche, Agrochimiche e delle Produzioni Animali - Sezione Scienze Agronomiche, Università degli Studi di Catania, Via Valdisavoia 5, 95123 Catania, Italy.
authors.forename: Danilo
authors.initials: D
authors.lastname: Scordia
authors.forename: Salvatore L
authors.initials: SL
authors.lastname: Cosentino
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Jeffries
mesh_terms: D001674:Bioelectric Energy Sources; D001709:Biotechnology / Q000379:methods*; D004563:Electrochemistry / Q000379:methods; D004583:Electrons; D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000737:chemistry*; D017019:Methanosarcinaceae / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D031786:Saccharum / Q000378:metabolism*; D013696:Temperature
chemical_list: D000431:Ethanol; D008697:Methane; D010100:Oxygen