title: Biotechnological production of xylitol in a three-phase fluidized bed bioreactor with immobilized yeast cells in Ca-alginate beads.
abstract: Cells of Candida guilliermondii entrapped in Ca-alginate beads were used for xylitol production, from concentrated hemicellulose hydrolyzate of sugarcane bagasse, in a fluidized bed bioreactor (FBR). The maximum xylitol concentration 28.9 g xylitol/L was obtained at a high aeration rate of 600 mL/min after 70 h of fermentation, indicating that the use of high aeration rate in this system is favored for better oxygen transfer into the immobilized cells. The specific xylitol productivity and the xylitol yield were of 0.4 g xylitol/L.h and 0.58 g xylitol/g xylose respectively. The immobilization efficiency at the end of the fermentation was of 65 %. After 90 h of fermentation xylitol productivity and yield decreased to 0.25 g xylitol/L.h and 0.47 g xylitol/g xylose respectively, indicating the beginning of xylitol consumption by the yeast. The use of FBR system with immobilized cells presented high xylitol yield and productivity.
authors.affiliation: Biotechnology Department, University of São Paulo/Lorena, Brazil. bsarrouh@yahoo.es
authors.forename: Boutros
authors.initials: B
authors.lastname: Fouad Sarrouh
authors.forename: Diego
authors.initials: D
authors.lastname: Tresinari Dos Santos
authors.forename: Silvio
authors.initials: S
authors.lastname: Silvério da Silva
mesh_terms: D000464:Alginates; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods; D002175:Candida / Q000502:physiology*; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D049109:Cell Proliferation; D018914:Cells, Immobilized; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D008863:Microspheres; D014993:Xylitol / Q000378:metabolism*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D014993:Xylitol