Figure 1 -- Cocktail for chips: Mixture of enzymes converts wood chips into hydrogen. Source: Virginia Tech.
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In tests with corn stover, about 9% of the cellulose in that waste ultimately was converted into DMF. “The yield of DMF isn’t fabulous yet, but that second step hasn’t been optimized,” notes Raines. “Our process is so general I think we can make DMF out of any type of biomass,” he adds. The Virginia Tech/Georgia/Oak Ridge team relies on a cocktail of 14 enzymes and one coenzyme to make hydrogen. The endothermic reactions take place in water at about 90°F. “In addition to converting the chemical energy from the sugar, the process also converts the low-temperature thermal energy into high-quality hydrogen energy,” notes Percival Zhang, an assistant professor at Virginia Tech (Figure 1). The hydrogen production rate is over eight times faster than what the researchers have previously achieved using starch. Yield also is high, ∼11.2 H2/anhydroglucose unit of cellulosic materials, the highest level yet reported, they claim. The team used cellulosic material isolated from wood chips but the technique also could handle crop waste or switch grass.