(573e) Effects of Reactor Type on High Solids Enzymatic Hydrolysis of Dilute Acid Pretreated Corn Stover

Ethanol produced from lignocellulosic biomass has become a promising alternative transportation fuel to gasoline. In a typical biochemical process, the majority of the hemicellulose fraction of biomass is hydrolyzed in a chemical pretreatment process, while the majority of the cellulose fraction is converted through enzymatic hydrolysis. A combination of pretreatment and enzymatic hydrolysis performed at high concentrations of solids can potentially improve process economics. At high concentrations of solids, smaller reactors are needed for the same product throughput, which decreases capital costs and increases product concentration. However, at high solid levels there can be difficulties in pumping, mixing, pH and temperature control, and lower total conversion of cellulose. In this work different scaled-down enzymatic hydrolysis reactors were tested and evaluated for their efficiency in converting high solids loadings of biomass. Three types of reactors were compared: vertical stirred tank, horizontal tank with center drive shaft, and horizontally rotating jars. In addition, the horizontally rotating jars were varied in number of baffles and amount of attrition media. The affects of mixing speed, presence of baffles, and amount of attrition media are shown. Cellulose conversion results are compared for all reactors.