(787d) Solvent Based Pretreatment (N-methyl morpholine oxide) for Enhanced Enzymatic Hydrolysis of Dissolving Pulp and Sugarcane Bagasse

Authors: 
Ramakrishnan, S., Florida A&M University - Florida State University


The first step in the conversion process of biomass to biofuels or hydrogen lies in picking an environmentally friendly solvent which is capable of breaking up the crystalline microstructure of cellulose.  Once the cellulose is in suspension, enzymes (cellulases) are added to the reactor to hydrolyze the cellulose to simple sugars that are then fermented by bacteria to biofuels.  Till date, a number of solvents have been used for pretreatment of biomass and for reprecipitating it by the addition of an anti-solvent thus making it a multi-stage process.  In this work, it is shown that N-methyl morpholine oxide is a good solvent for pretreatment of crystalling pulp and sugarcane bagasse.  Sugarcane bagasse and dissolving pulp of degree of polymerization 1160 are used as the substrate and Accellerase 1000 and 1500 purchased from Genentech are the cellulases used.  The rates of enzymatic hydrolysis and total sugars released are studied as a function of solution conditions – solution pH, temperature and enzyme loading.  These studies reveal that the enzymes are active in NMMO and that the rates of hydrolysis of cellulose pretreated with NMMO are comparable to the rates of hydrolysis of regenerated cellulose suspended in aqueous buffer solutions. A comparison of enzymatic hydrolysis after NMMO treatment of sugarcane bagasse reveals that the rates and yields are comparable and in certain instances higher than acid pretreatment followed by steam explosion.  A mathematical model to predict enzymatic hydrolysis based on lumped kinetic modeling is also proposed.