title: Overliming detoxification of pyrolytic sugar syrup for direct fermentation of levoglucosan to ethanol.
abstract: The application of pyrolytic sugars for biofuel production through fermentation is challenged by inhibitory contaminant compounds. Inhibition is so severe that only 0.25% sugar syrup can be used. In this study, overliming was tested as a simple detoxification method, using the Escherichia coli KO11+ lgk to directly convert levoglucosan into ethanol. After treatment with at least 14.8 g/L of Ca(OH)2, fermentation with 2% (w/v) pyrolytic sugar syrup was observed with no inhibition of ethanol production. Further investigation of treatment time and temperature showed that 8-16 h of treatment at 20°C, and 1-4 h of treatment at 60°C are necessary to obtain consistent ethanol production. The samples treated with 18.5 g/L Ca(OH)2 at 60°C for 4 h showed no inhibition at 2.5%. Multiple contaminants removed by the overliming treatment were identified. This study demonstrates that overliming is a promising method for detoxification of pyrolytic sugars for fermentation.
authors.affiliation: Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Zhanyou
authors.initials: Z
authors.lastname: Chi
authors.forename: Marjorie
authors.initials: M
authors.lastname: Rover
authors.forename: Erin
authors.initials: E
authors.lastname: Jun
authors.forename: Mark
authors.initials: M
authors.lastname: Deaton
authors.forename: Patrick
authors.initials: P
authors.lastname: Johnston
authors.forename: Robert C
authors.initials: RC
authors.lastname: Brown
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Wen
authors.forename: Laura R
authors.initials: LR
authors.lastname: Jarboe
mesh_terms: D056804:Biofuels; D002126:Calcium Hydroxide / Q000494:pharmacology; D002241:Carbohydrates / Q000494:pharmacology*; D004187:Disaccharides / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects*; D005947:Glucose / Q000031:analogs & derivatives* / Q000378:metabolism; D006358:Hot Temperature; D013997:Time Factors
chemical_list: D056804:Biofuels; D002241:Carbohydrates; D004187:Disaccharides; C524805:glucopyranosyl-(1-4)-1,6-anhydroglucopyranose; D000431:Ethanol; C014989:1,6-anhydro-beta-glucopyranose; D005947:Glucose; D002126:Calcium Hydroxide
keywords: Biomass; Contaminants; Levoglucosan; Overliming; Pyrolysis