Characterization of Biomass Traits in Grain Amaranth (Amaranthus spp.)

Amaranth is an herbaceous annual with upright habit in both temperate and tropical climates. Current cultivated amaranth is mainly used as a food source for humans and forage for animals. Some species are also used for landscaping in Americas. However, amaranth as a biomass based energy resource has not been well-addressed. In this study, the cell wall components of amaranth (Amaranthus australis) and its glucose concentration under enzymatic, sulfuric acid and ionic liquid assays were characterization, in comparison with corn stover, switchgrass and sorghum. For cell wall component analysis, acid detergent lignin (ADL), acid detergent fiber (ADF), and neutral detergent fiber (NDF) from the dry matter (DM) of whole plants were analyzed and subsequently converted to lignin, cellulose and hemicellulose contents respectively. Significant variations in cell wall components among these four species were found. Corn stover cellulose gave the highest glucose yields under three treatments, compared to other three species. However, amaranth, switchgrass and sorghum could give glucose yields with no significant difference by the three assay methods at certain time of treatment. Compare to other non-food bioenergy crops, amaranth contains close amounts of cell wall components and glucose when digested at a certain time, indicating that Amaranthus species has potential for alternative biofuel crop.