Variables That Affect Xylitol Production from Sugarcane Bagasse Hydrolysate in a Zeolite Fluidized Bed Reactor

摘要

The operational conditions for xylitol production by fermentation of sugarcane bagasse hydrolysate in a fluidized bed reactor with cells immobilized on zeolite were evaluated.Fermentations were carried out under different conditions of air flowrate(0.0125-0.0375 vvm),zeolite mass(100-200 g),initial pH(4-6),and xylose concentration(40-60 g/L),according to a 2~4 full factorial design.The air flowrate increase resulted in a metabolic deviation from product to biomass formation.On the other hand,the pH increase favored both the xylitol yield(Yp/s)and volumetric productivity(Q_P),and the xylose concentration increase positively influenced the xylitol concentration.The best operational conditions evaluated were based on the use of an air flowrate of 0.0125 wm,100 g of zeolite,pH 6,and xylose concentration of 60 g/L.Under these conditions,38.5 g/L of xylitol were obtained,with a Y_(P/S)of 0.72 g/g,Q_P of 0.32 g/L centre dot h,and cell retention of 25.9%.