title: Supercritical fluid extraction of a lignocellulosic hydrolysate of spruce for detoxification and to facilitate analysis of inhibitors.
abstract: This work describes a novel approach to detoxify lignocellulosic hydrolysates and facilitate the analysis of inhibitory compounds, namely supercritical fluid extraction (SFE). The efficiency of the fermentation of lignocellulosic dilute-acid hydrolysates depends upon the composition of the hydrolysate and the organism used. Furthermore, it has been shown that inhibitors in the hydrolysate reduce the fermentation yield. This knowledge has given rise to the need to identify and remove the inhibiting compounds. Sample clean-up or work-up steps, to provide a clean and concentrated sample for the analytical system, facilitate the characterization of inhibitors, or indeed any compound in the hydrolysates. Removal of inhibitors was performed with countercurrent flow supercritical fluid extraction of liquid hydrolysates. Three different groups of inhibitors (furan derivatives, phenolic compounds, and aliphatic acids) and sugars were subsequently analyzed in the hydrolysate, extracted hydrolysate, and extract. The effect of the SFE treatment was examined with respect to fermentability with Saccharomyces cerevisiae. Not only did the extraction provide a clean and concentrated sample (extract) for analysis, but also a hydrolysate with increased fermentability as well as lower concentrations of inhibitors such as phenolics and furan derivatives.
authors.affiliation: Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden. per.persson@analykem.lu.se
authors.forename: Per
authors.initials: P
authors.lastname: Persson
authors.forename: Simona
authors.initials: S
authors.lastname: Larsson
authors.forename: Leif J
authors.initials: LJ
authors.lastname: Jönsson
authors.forename: Nils-Olof
authors.initials: NO
authors.lastname: Nilvebrant
authors.forename: Björn
authors.initials: B
authors.lastname: Sivik
authors.forename: Florentina
authors.initials: F
authors.lastname: Munteanu
authors.forename: Lars
authors.initials: L
authors.lastname: Thörneby
authors.forename: Lo
authors.initials: L
authors.lastname: Gorton
mesh_terms: D019149:Bioreactors; D002245:Carbon Dioxide / Q000493:pharmacokinetics*; D002482:Cellulose / Q000302:isolation & purification / Q000378:metabolism; D025924:Chromatography, Supercritical Fluid / Q000295:instrumentation / Q000379:methods*; D004791:Enzyme Inhibitors / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D005285:Fermentation; D005662:Furaldehyde / Q000032:analysis / Q000378:metabolism; D006868:Hydrolysis; D008658:Inactivation, Metabolic; D008031:Lignin / Q000302:isolation & purification* / Q000378:metabolism*; D010636:Phenols / Q000032:analysis / Q000378:metabolism; D028222:Picea / Q000187:drug effects / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D005227:Fatty Acids; D010636:Phenols; D002245:Carbon Dioxide; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; D005662:Furaldehyde