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| Glucan Biopolymers
Glucan biopolymers are the primary storage and structural components of plants.
- Glucans represent some of the most important sources of renewable bioenergy on the planet, being composed of polymerized glucose.
- Glucan biopolymers in plant biomass include Starch, Cellulose and Mixed-Linkage Glucans.
- Glucans mixed with glycans such as hemicellulose make up the cell wall matrix of plants. Cell walls are variously cross-linked by lignin, providing physical strength and resistance to degradation.
- Most of the starch in plants is stored in grain or tubers.
Composition Comparison of Different Bioenergy Crops*. (For comparison: Corn Grain is 7,000 BTU/lb, 71% Starch, 4% Cellulose) |
| Corn Cob | Corn Stover | Sugar Cane | Sweet Sorghum | Switch
-grass | Miscan -thus | Poplar Hybrid | | Energy Available (BTU/lb) | 7,375 | 7,967 | 8,149 |
| 7,886 |
| 8,384 | | Starch | - | - | - | - | - | - | - | | Cellulose | 34% | 35% | 32-48% | 23% | 35% | 44-51% | 39% | | Hemicellulose | 36% | 22% | 19-24% | 14% | 27% | 42-50% | 17% | | - Xylan component | 31% | 18% | 20% | 12% | 23% | | 13% | | - Arabinan component | 3% | 3% | 2% | 1% | 3% | | 1% | | Lignin | 18% | 17% | 23-32% | 11% | 17% | 13-20% | 25% | | Ash | 2% | 10% | 4% | 5% | 6% | 3% | 2% |
* Scurlock (2008) Factsheet: Bioenergy Feedstock Characteristics, Oak Ridge National Laboratory. | |
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