Articles

High sugar Eastern gamagrass (Tripsacum dactyloides L) cultivars as potential biofuel feedstock


Abstract


Maize (Zea mays L) is the leading biofuel crop in the United States. Production of ethanol from maize requires relatively high energy inputs from petroleum-based products. The net energy required for growing maize and consequent contribution to atmospheric CO2 make using maize for ethanol production inefficient. Warm season perennial grasses have excellent potential as alternative biofuel feedstocks. However, one of the drawbacks of using these grasses is their high lignin content, which restricts breakdown of cellulose into carbohydrates and sugar for fermentation into ethanol. This results in low net ethanol yield, a major challenge for biofuel production from cellulosic feedstocks. Eastern gamagrass (Tripsacum dactyloides L) is a warm season native American grass related to maize. To evaluate potential of Eastern gamagrass and gamagrass-Zea recombinant lines as a biofuel feedstock, seven varieties were analyzed for their chemical composition and fermentable sugar production. Based on total sugar yield, gamagrass-Zea recombinant cultivars Eagle Point Devil Corn and Sun Devil reached 595.8 and 456.5 mg g-1 raw biomass, respectively. Compared to the other gamagrass varieties and energy crops switchgrass and bermudagrass, these gamagrass-Zea recombinants gave a significantly higher (P<0.05) sugar yield. DNA fingerprinting revealed Sun Devil contains introgressed Zea alleles at three loci associated with sugar synthesis. At theoretical yield of 386.1 liters of ethanol per ton of dry biomass, the Eagle Point Devil Corn cultivar has potential as a high yielding biofuel feedstock. The next step will be to conduct agronomic studies to evaluate field performance and biomass yield of this promising new feedstock.

Keywords

Eastern gamagrass; Tripsacum; biofuel; ethanol; energy crop; sugar

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