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Bonnie R. Hames Steven R. Thomas Amie D. Sluiter Christine J. Roth David W. Templeton 《Applied biochemistry and biotechnology》2003,105(1-3):5-16
New, rapid, and inexpensive methods that monitor the chemical composition of corn stover and corn stover-derived samples are
a key element to enabling the commercialization of processes that convert stover to fuels and chemicals. These new techniques
combine near infrared (NIR) spectroscopy and projection to latent structures (PLS) multivariate analysis to allow the compositional
analysis of hundreds of samples in 1 d at a cost of about $10 each. The new NIR/PLS rapid analysis methods can also be used
to support a variety of research projects that would have been too costly to pursue by traditional methods. 相似文献
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The precise quantitative analysis of biomass sugars is a very important step in the conversion of biomass feedstocks to fuels
and chemicals. However, the most accurate method of biomass sugar analysis is based on the gas chromatography analysis of
derivatized sugars either as alditol acetates or trimethylsilanes. The derivatization method is time consuming but the alternative
high-performance liquid chromatography (HPLC) method cannot resolve most sugars found in biomass hydrolysates. We have demonstrated
for the first time that by careful manipulation of the HPLC mobile phase, biomass monomeric sugars (arabinose, xylose, fructose,
glucose, mannose, and galactose) can be analyzed quantitatively and there is excellent baseline resolution of all the sugars.
This method was demonstrated for standard sugars, pretreated corn stover liquid and solid fractions. Our method can also be
used to analyze dimeric sugars (cellobiose and sucrose). 相似文献
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David W. Templeton Amie D. Sluiter Tammy K. Hayward Bonnie R. Hames Steven R. Thomas 《Cellulose (London, England)》2009,16(4):621-639
Corn stover, the above-ground, non-grain portion of the crop, is a large, currently available source of biomass that potentially
could be collected as a biofuels feedstock. Biomass conversion process economics are directly affected by the overall biochemical
conversion yield, which is assumed to be proportional to the carbohydrate content of the feedstock materials used in the process.
Variability in the feedstock carbohydrate levels affects the maximum theoretical biofuels yield and may influence the optimum
pretreatment or saccharification conditions. The aim of this study is to assess the extent to which commercial hybrid corn
stover composition varies and begin to partition the variation among genetic, environmental, or annual influences. A rapid
compositional analysis method using near-infrared spectroscopy/partial least squares multivariate modeling (NIR/PLS) was used
to evaluate compositional variation among 508 commercial hybrid corn stover samples collected from 47 sites in eight Corn
Belt states after the 2001, 2002, and 2003 harvests. The major components of the corn stover, reported as average (standard
deviation) % dry weight, whole biomass basis, were glucan 31.9 (2.0), xylan 18.9 (1.3), solubles composite 17.9 (4.1), and
lignin (corrected for protein) 13.3 (1.1). We observed wide variability in the major corn stover components. Much of the variation
observed in the structural components (on a whole biomass basis) is due to the large variation found in the soluble components.
Analysis of variance (ANOVA) showed that the harvest year had the strongest effect on corn stover compositional variation,
followed by location and then variety. The NIR/PLS rapid analysis method used here is well suited to testing large numbers
of samples, as tested in this study, and will support feedstock improvement and biofuels process research. 相似文献
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Identification of microbial inhibitory functional groups in corn stover hydrolysate by carbon-13 nuclear magnetic resonance spectroscopy 总被引:6,自引:0,他引:6
Dilute-acid biomass hydrolysates contain biomass degradation products that are inhibitory to cell growth and fermentation.
Overliming with Ca(OH)2 has been found to be one of the most effective methods for detoxifying the dilute-acid hydrolysate for ethanol production.
However, the mechanism of overliming is not well understood. Carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy was used to elucidate the functional groups involved in the overliming reaction. The 13C-NMR spectra showed that the major functional groups removed during the overliming process were aliphatic and aromatic acids
or esters, and other aromatic and aliphatic compounds. Ketone and aldehyde functionalities were not detected in the spectra.
This is the first time that 13C-NMR has been used to elucidate the overliming reaction. 相似文献
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Thompson David N. Hames Bonnie R. Reddy C. A. Grethlein Hans E. 《Applied biochemistry and biotechnology》1998,(1):967-982
The abilities of lignin peroxidase (LIP) and manganese peroxidase (MNP) fromPhanerochaete chrysosporium to degrade an insoluble hardwood lignin in vitro in aqueous media were tested. Neither LIP nor MNP appreciably changed the
mass or lignin content, although both produced small amounts of unique solubilized lignin fragments. Treatment with both LIP
and MNP, however, decreased the mass by 11%, decreased the lignin content by 5.1% (4.2% as total weight), and solubilized
unique lignin-derived molecules. These results suggest that LIP and MNP synergistically degrade high molecular weight insoluble
lignin, but singly, neither enzyme is sufficient to effect lignin degradation. 相似文献
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Hames B 《Applied biochemistry and biotechnology》2008,148(1-3):257-260
Special Session B at the 29th Symposium on Biotechnology for Fuels and Chemicals was the first invited session at this symposium
devoted to analytical methods. The special topic was added in response to numerous requests for information on new and innovative
methods that could be applied in the growing renewable fuels industry. Presentation topics include analytical methods for
the characterization and analysis of maize traits, tools for investigating cell wall limitations to enzymatic degradation,
methods for customizing enzyme cocktails for biomass, new techniques for the analysis of carbohydrates, analytical methods
that enhance our understanding of pretreatment, improved methods for monitoring process intermediates, and published standard
analytical methods for biomass conversion processes. 相似文献
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Cyclic ortho esters undergo stereoselective and regioselective reaction with phenols when treated with BF(3) x OEt(2) at low temperatures. Attack of the phenol on the ortho ester occurs at an open carbon para to electron-donating groups on the phenol ("C-addition") or at the phenolic hydroxyl group ("O-addition") depending on the nature of the cation formed from reaction of the ortho ester and BF(3) x OEt(2). Products resulting from O-addition undergo reversion to a mixture of starting phenol, C-addition product, and O-addition product if treated with BF(3) x OEt(2) at room temperature, but C-addition products are stable under the same conditions. X-ray structural analysis of the C-addition compound indicates that its stereochemistry is opposite to that observed in reaction of similar ortho esters with chloride from TMSCl. However, the stereochemistry of the reaction can be rationalized by the ability of the ortho ester to isomerize via an intermediate benzylic cation and examination of the preferred trajectory of attack of the nucleophile on the intermediate oxonium ion. 相似文献
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