When biofuels researcher Abolghasem Shahbazi went to visit his colleague’s laboratory – a swine waste lagoon at the North Carolina Agricultural and Technical State University research farm in Greensboro, N.C. – he was struck by the amount of cattails that his colleague was using in the constructed wetland to purify the lagoon water.
“As I went to visit his site, I saw that every year he was growing these huge amounts of plants and then nobody was doing anything with them,” Shahbazi said. “Everything died down and then went into the water and the next year they grew back again with very little effort. Being involved in biofuels research, I thought, ‘this is an excellent feedstock.’” Shahbazi is a professor and director of the biological engineering program at North Carolina Agricultural and technical State University.
Shahbazi said students at the university recently completed a non-optimized trial where they used the cattails as feedstock to produce cellulosic ethanol. The students cut the cattails at ground level, dried the plants whole and then ground them. Sodium hydroxide was used to pretreat the ground feedstock and multiple enzymes were used to produce two different sugars which were fermented using two types of yeast.
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Shahbazi said on average, 7.2 dry tons of cattails were harvested per acre. The cellulose conversion rate was 43.4 percent in the non-optimized test. This number can be improved significantly, he said, because much of the cellulose was washed out during the pretreatment process and the fermentation process can be optimized to maximize yield.
Shahbazi said the next step for the researchers is to find additional funding so the scope of the research can be expanded and the fermentations process can be optimized. He said the researchers are looking at an integrated project that can use cattails to treat swine wastewater lagoons while producing feedstock for ethanol production.
“With North Carolina having so many hogs and so much hog waste, there may be an opportunity to combine these two efforts and then come up with a strategy for creating a viable feedstock from that,” Shahbazi said.
