title: Grape marc as a source of carbohydrates for bioethanol: Chemical composition, pre-treatment and saccharification.
abstract: Global grape production could generate up to 13 Mt/yr of wasted biomass. The compositions of Cabernet Sauvignon (red marc) and Sauvignon Blanc (white marc) were analyzed with a view to using marc as raw material for biofuel production. On a dry weight basis, 31-54% w/w of the grape marc consisted of carbohydrate, of which 47-80% was soluble in aqueous media. Ethanol insoluble residues consisted mainly of polyphenols, pectic polysaccharides, heteroxylans and cellulose. Acid and thermal pre-treatments were investigated for their effects on subsequent cellulose saccharification. A 0.5M sulfuric acid pre-treatment yielded a 10% increase in the amount of liberated glucose after enzymatic saccharification. The theoretical amount of bioethanol that could be produced by fermentation of grape marc was up to 400 L/t. However, bioethanol from only soluble carbohydrates could yield 270 L/t, leaving a polyphenol enriched fraction that may be used in animal feed or as fertilizer.
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Kendall R
authors.initials: KR
authors.lastname: Corbin
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Yves S Y
authors.initials: YS
authors.lastname: Hsieh
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Natalie S
authors.initials: NS
authors.lastname: Betts
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia; The Australian Research Council Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Caitlin S
authors.initials: CS
authors.lastname: Byrt
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Marilyn
authors.initials: M
authors.lastname: Henderson
authors.affiliation: Plant Physiology, Department of Horticulture, Agricultural Science Center North, University of Kentucky, Lexington, KY 40546, United States.
authors.forename: Jozsef
authors.initials: J
authors.lastname: Stork
authors.affiliation: Plant Physiology, Department of Horticulture, Agricultural Science Center North, University of Kentucky, Lexington, KY 40546, United States.
authors.forename: Seth
authors.initials: S
authors.lastname: DeBolt
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
authors.forename: Geoffrey B
authors.initials: GB
authors.lastname: Fincher
authors.affiliation: The Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia. Electronic address: Rachel.burton@adelaide.edu.au.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Burton
mesh_terms: D000821:Animal Feed; D056804:Biofuels; D018533:Biomass; D002482:Cellulose / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation / Q000502:physiology; D005947:Glucose / Q000737:chemistry*; D059808:Polyphenols / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry; D027843:Vitis / Q000737:chemistry*
chemical_list: D056804:Biofuels; D059808:Polyphenols; D011134:Polysaccharides; D013464:Sulfuric Acids; D000431:Ethanol; D002482:Cellulose; D005947:Glucose; C033158:sulfuric acid
keywords: Bioethanol; Grape marc; Polysaccharide; Pre-treatment; Saccharification