title: Xylitol production from DEO hydrolysate of corn stover by Pichia stipitis YS-30.
abstract: Corn stover that had been treated with vapor-phase diethyl oxalate released a mixture of mono- and oligosaccharides consisting mainly of xylose and glucose. Following overliming and neutralization, a D-xylulokinase mutant of Pichia stipitis, FPL-YS30 (xyl3-∆1), converted the stover hydrolysate into xylitol. This research examined the effects of phosphoric or gluconic acids used for neutralization and urea or ammonium sulfate used as nitrogen sources. Phosphoric acid improved color and removal of phenolic compounds. D-Gluconic acid enhanced cell growth. Ammonium sulfate increased cell yield and maximum specific cell growth rate independently of the acid used for neutralization. The highest xylitol yield (0.61 g(xylitol)/g(xylose)) and volumetric productivity (0.18 g(xylitol)/g(xylose )l) were obtained in hydrolysate neutralized with phosphoric acid. However, when urea was the nitrogen source the cell yield was less than half of that obtained with ammonium sulfate.
authors.affiliation: Departamento de Biotecnologia, DEBIQ, Escola de Engenharia de Lorena, EEL, USP, Universidade de São Paulo, P.O Box 116, Lorena, SP 12600-970, Brazil. rita@debiq.eel.usp.br
authors.forename: Rita C L B
authors.initials: RC
authors.lastname: Rodrigues
authors.forename: William R
authors.initials: WR
authors.lastname: Kenealy
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Jeffries
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D005285:Fermentation; D005942:Gluconates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D010843:Pichia / Q000201:enzymology* / Q000254:growth & development; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism; D003313:Zea mays
chemical_list: D005942:Gluconates; D010756:Phosphoric Acids; D014994:Xylose; C030242:phosphoric acid; D017853:Phosphotransferases (Alcohol Group Acceptor); C032700:xylulokinase; C030691:gluconic acid; D000645:Ammonium Sulfate; D014993:Xylitol