Lignocellulosic biomass is a potential source of fermentable sugars such as
glucose. Enzymatic hydrolysis of cellulose is a viable method of solubilizing the
glucose from biomass, but the cellulose fraction of native lignocellulosic material
is shielded from enzymatic attack by the lignin-hemicellulose matrix
surrounding it. Pretreating lignocellulosic biomass with dilute sulfuric acid at
high temperatures solubilizes hemicellulose, rendering the cellulose fraction
more susceptible to enzymatic hydrolysis. Evaluation of dilute-acid, high-temperature
pretreatments depends on polysaccharide analysis of the two
fractions resulting from a pretreatment, prehydrolyzed solids(PHS) and
prehydrolyzate liquid(PH). The polysaccharide analysis is based on a method
described by the National Renewable Energy Laboratory and involves a two-stage
sulfuric acid hydrolysis followed by HPLC quantification using ion-moderated
partition chromatography and refractive index detection. The subject
of this thesis is identifying and quantifying the sources of error associated with
the polysaccharide analysis and the error associated with the evaluation of the
effects of pretreatment on the polysaccharide fractions of switchgrass and poplar.
This was addressed by conducting replicate polysaccharide analyses on single
samples of native biomass, PHS, and PH. The variability associated with these
measurements was compared to the variability associated with replicate analyses
of identically pretreated biomass. It was found that the use of sugar standards to correct for sugar destroyed during the analysis adds error and most likely
overestimates the amount of sugar from biomass actually destroyed. It is evident
that assuming a volume after neutralization of the hydrolyzed biomass sample is
more reproducible than measuring the volume. When using a batch-type reactor
and the temperature and acid parameters used in this study,140°C-180°C/ 0.6-1.2
% sulfuric acid (w/w), it is evident that the major source of error in evaluating
pretreatment conditions is the pretreatment itself, not the analysis. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27278 |
| Date | 17 June 1994 |
| Creators | Fenske, John J. |
| Contributors | Penner, Michael H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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