title: The effect of mixing on the liquefaction and saccharification of cellulosic fibers.
abstract: The enzymatic hydrolysis of cellulosic material is a key step in the biochemical routes for production of renewable fuels and chemicals. This must be performed at high solids to be economically viable. High solids operations creates numerous processing challenges, most importantly the limitations due to mass transfer and poor mixing of enzymes in the cellulose suspensions. We use magnetic resonance imaging (MRI), a cylindrical penetrometer, and HPLC to demonstrate the importance of spatial homogeneity in the distribution of enzyme on the rates of liquefaction of the substrate and in the suspension mechanical strength. Our results show that the largest mechanical strength changes occur in a narrow interval of time during the initial stages of conversion. Differences in enzyme concentration distribution occurring at the centimeter-scale produced order of magnitude differences in liquefaction and saccharification rates, supporting the hypothesis that mixing quality has a major influence in both liquefaction and saccharification rates.
authors.affiliation: Department of Chemical & Materials Science Engineering, University of California, Davis, CA, USA. dmlavenson@ucdavis.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Lavenson
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Tozzi
authors.forename: Nardrapee
authors.initials: N
authors.lastname: Karuna
authors.forename: Tina
authors.initials: T
authors.lastname: Jeoh
authors.forename: Robert L
authors.initials: RL
authors.lastname: Powell
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McCarthy
mesh_terms: D050260:Carbohydrate Metabolism; D002482:Cellulose / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D008279:Magnetic Resonance Imaging
chemical_list: D002482:Cellulose