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29 results on '"Julson, James"'

19. Catalyzed modified clean fractionation of switchgrass

Author

UCL - SST/ELI/ELIM - Applied Microbiology, Cybulska, Iwona, Brudecki, Grzegorz P., Hankerson, Brett R., Julson, James L., Lei, Hanwu, UCL - SST/ELI/ELIM - Applied Microbiology, Cybulska, Iwona, Brudecki, Grzegorz P., Hankerson, Brett R., Julson, James L., and Lei, Hanwu

Abstract

Switchgrass was used as a lignocellulosic feedstock for second generation ethanol production, after pretreatment using sulfuric acid-catalyzed modified clean fractionation based on NREL’s (National Renewable Energy Laboratory) original procedure. Optimization of temperature, catalyst concentration and solvent composition was performed using Response Surface Methodology, and 59.03 ± 7.01% lignin recovery, 84.85 ± 1.34% glucose, and 44.11 ± 3.44% aqueous fraction xylose yields were obtained at 140.00 °C, 0.46% w/w catalyst concentration, 36.71% w/w ethyl acetate concentration, and 25.00% w/w ethanol concentration. The cellulose fraction did not inhibit the fermentation performance of Saccharomyces cerevisiae and resulted in an ethanol yield of 89.60 ± 2.1%.

Published
2013

20. Comparative study of organosolv lignin extracted from prairie cordgrass, switchgrass and corn stover

Author

UCL - SST/ELI/ELIM - Applied Microbiology, Cybulska, Iwona, Brudecki, Grzegorz, Rosentrater, Kurt, Julson, James L., Lei, Hanwu, UCL - SST/ELI/ELIM - Applied Microbiology, Cybulska, Iwona, Brudecki, Grzegorz, Rosentrater, Kurt, Julson, James L., and Lei, Hanwu

Abstract

Lignin extracted from prairie cordgrass, switchgrass, and corn stover (using ethyl acetate–ethanol–water organosolv pretreatment) was analyzed and characterized using several methods. These methods included analysis of purity (by determination of Klason lignin, carbohydrate, and ash contents), solubility (with several organic solvents), phenolic group analysis (ultraviolet ionization difference spectra, and nitrobenzene oxidation), and general functional group analysis (by 1H NMR). Results showed that all the examined lignin samples were relatively pure (contained over 50% Klason lignin, less than 5% carbohydrate contamination, and less than 3% ash), but switchgrass-derived lignin was observed to be the purest. All the lignins were found to contain high amounts of phenolic groups, while switchgrass-derived lignin was the most phenolic, according to the ionization difference spectra. Nitrobenzene oxidation revealed that all the lignin samples contained available guaiacyl units in high amounts.

Published
2012

21. Optimization of clean fractionation processing as a pre-treatment technology for prairie cordgrass

Author

UCL - SST/ELI/ELIM - Applied Microbiology, Brudecki, Grzegorz, Cybulska, Iwona, Rosentrater, Kurt, Julson, James, UCL - SST/ELI/ELIM - Applied Microbiology, Brudecki, Grzegorz, Cybulska, Iwona, Rosentrater, Kurt, and Julson, James

Abstract

The main objective of this study was to fractionate prairie cordgrass (PCG) obtaining the highest cellulose digestibility. Following clean fractionation (CF) processing, the PCG lignocellulosic biomass was fractionated into three main building blocks: cellulose, hemicellulose and lignin. Effects of processing factors such as time, temperature, catalyst concentration and organic solvent mixture composition were evaluated. Organic solvent–aqueous mixture contained methyl isobutyl ketone (MIBK), ethanol and water in different proportions. Sulfuric acid was used as a catalyst. In order to evaluate the degree of pre-treatment, enzymatic saccharification was employed on the cellulose fraction obtained from the CF process. Response surface methodology was used for process optimization and statistical analysis. Optimal conditions (39 min, 154 °C, 0.69% catalyst and 9% MIBK) resulted in 84% glucose yield and 87% acid insoluble lignin (AIL).

Published
2012

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