title: Improved enzymatic saccharification of steam exploded cotton stalk using alkaline extraction and fermentation of cellulosic sugars into ethanol.
abstract: Cotton stalk, a widely available and cheap agricultural residue lacking economic alternatives, was subjected to steam explosion in the range 170-200°C for 5min. Steam explosion at 200°C and 5min led to significant hemicellulose solubilization (71.90±0.10%). Alkaline extraction of steam exploded cotton stalk (SECOH) using 3% NaOH at room temperature for 6h led to 85.07±1.43% lignin removal with complete hemicellulose solubilization. Besides, this combined pretreatment allowed a high recovery of the cellulosic fraction from the biomass. Enzymatic saccharification was studied between steam exploded cotton stalk (SECS) and SECOH using different cellulase loadings. SECOH gave a maximum of 785.30±8.28mg/g reducing sugars with saccharification efficiency of 82.13±0.72%. Subsequently, fermentation of SECOH hydrolysate containing sugars (68.20±1.16g/L) with Saccharomyces cerevisiae produced 23.17±0.84g/L ethanol with 0.44g/g yield.
authors.affiliation: Department of Microbiology, Osmania University, Hyderabad 500 007, India.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Keshav
authors.affiliation: Department of Microbiology, Osmania University, Hyderabad 500 007, India.
authors.forename: Shaik
authors.initials: S
authors.lastname: Naseeruddin
authors.affiliation: Department of Microbiology, Osmania University, Hyderabad 500 007, India. Electronic address: vrlinga@gmail.com.
authors.forename: L Venkateswar
authors.initials: LV
authors.lastname: Rao
mesh_terms: D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects*; D003368:Gossypium / Q000737:chemistry* / Q000187:drug effects; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D012972:Sodium Hydroxide / Q000494:pharmacology*; D013227:Steam; D013997:Time Factors
chemical_list: D013227:Steam; D000431:Ethanol; D012972:Sodium Hydroxide; D002482:Cellulose; D008031:Lignin; D002480:Cellulase
keywords: Cellulose; Cotton stalk; Enzymatic saccharification; Ethanol; Lignin; Steam explosion