Pilot scale alkaline pretreatment in a 1 ton/day continuous, horizontal pretreatment reactor

The goal of pretreatment is to physically or chemically modify lignocellulosic biomass to enhance the ability of enzymes to hydrolyze the remaining plant cell wall polysaccharides producing sugars for subsequent conversion to fuels and chemicals.  As exploited by the pulp and paper industry, alkaline pretreatment has the ability to solubilize much of the lignin in biomass while retaining most of the carbohydrates, which are then more amenable to enzymatic hydrolysis.  With an increased research focus to produce high value products from lignin, a low molecular weight lignin rich stream is also desirable.  Lignin extraction and carbohydrate retention have been reported for batch alkaline pretreatment at both the bench and pilot scales, but results of pilot scale, high-solids (≥ 20% w/w) continuous alkaline pretreatment have not been reported.  Alkaline pretreatment of corn stover was performed in a 1 ton/day continuous, large horizontal pretreatment reactor at temperatures and NaOH loadings ranging from 140°-180°C and 20-80 mg /g dry corn stover, respectively.  Lignin extraction and xylan and glucan retention yields will be presented, as well as glucose and xylose yields from enzymatic hydrolysis of the alkaline pretreated solids using a combination of cellulase and hemicellulase.