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Pretreatment is an important step to reduce the recalcitrance factors in biomass for effective biomass utilization. In particular, the choice of processing solvents in the pretreatment influences the quantity and quality of the final products. Although conventional organosolv pretreatments are effective, they are typically performed under harsh conditions. Compared to those approaches, recent studies have shown that the use of Deep Eutectic Solvents (DES) made up of a hydrogen bond donor and acceptor at the eutectic point can be a promising alternative as biomass processing solvents because of their good thermal stability and compatibility with natural components. In this study, DES pretreatment was applied to corn stover, which is the largest agricultural residue in the United States. The performance of the pretreatments was assessed by measuring the removal of xylan and lignin from the corn stover, as well as the production of glucose and xylose by subsequent enzymatic hydrolysis. The results indicated that the DES pretreatment resulted in significantly higher delignification rates (75%) than an organosolv pretreatment (35%) at the same processing temperature. The DES pretreatment also resulted in a more effective conversion of glucan (81%) and xylan (56%) than the organosolv pretreatment. The results indicated that DES pretreatment is a promising processing strategy for biomass utilization.
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Identification of features associated with plant cell wall recalcitrance to pretreatment by alkaline hydrogen peroxide in diverse bioenergy feedstocks using glycome profiling
A woody dicot (hybrid poplar), an herbaceous dicot (goldenrod), and a graminaceous monocot (corn stover) were subjected to alkaline hydrogen peroxide (AHP) pretreatment and subsequent enzymatic hydrolysis in order to assess how taxonomically and structurally diverse biomass feedstocks respond to a mild alkaline oxidative pretreatment and how differing features of the cell wall matrix contribute to its recalcitrance. Using glycome profiling, we determined changes in the extractability of non-cellulosic glucans following pretreatment by screening extracts of the pretreated walls with a panel of 155 cell wall glycan-directed monoclonal antibodies to determine differences in the abundance and distribution of non-cellulosic glycan epitopes in these extracts and assess pretreatment-induced changes in the structural integrity of the cell wall. Two taxonomically-dependent outcomes of pretreatment were identified that both improved the subsequent enzymatic hydrolysis yields but differed in their impacts on cell wall structural integrity. Specifically, it was revealed that goldenrod walls exhibited decreases in all classes of alkali-extractable glycans indicating their solubilization during pretreatment, which was accompanied by an improvement in the subsequent extractability of the remaining cell wall glycans. The corn stover walls did not show the same decreases in glycan abundance in extracts following pretreatment, but rather mild increases in all classes of cell wall glycans, indicating overall weaker associations between cell wall polymers and improved extractability. The hybrid poplar walls were relatively unaffected by pretreatment in terms of composition, enzymatic hydrolysis, and the extractability of cell wall glycans due presumably to their higher lignin content and denser vascular structure.
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- Award ID(s):
- 1336622
- PAR ID:
- 10043848
- Date Published:
- Journal Name:
- RSC Adv.
- Volume:
- 4
- Issue:
- 33
- ISSN:
- 2046-2069
- Page Range / eLocation ID:
- 17282 to 17292
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c4ra00824c
