title: Effect of starting xylose concentration on the microaerobic metabolism of Debaryomyces hansenii: the use of carbon material balances.
abstract: Xylitol production by Debaryomyces hansenii NRRL Y-7426 was performed on synthetic medium varying the initial xylose concentration between 50 and 300 g/L. The experimental results of these tests were used to investigate the effect of substrate level on xylose consumption by this yeast. Satisfactory values of product yield on substrate (0.74-0.83 g/g) as well as volumetric productivity (0.481-0.694 g/L x h) were obtained over a wide range of xylose levels (90-200 g/L), while a worsening of kinetic parameters took place at higher concentration, likely due to a substrate inhibition phenomenon. The metabolic behavior of D. hansenii was studied, under these conditions, through a carbon material balance to estimate the fractions of xylose consumed by the cell for different activities (xylitol production, biomass growth, and respiration) during the lag, exponential, and stationary phases.
authors: Department of Chemical and Process Engineering G.B. Bonino, University of Genoa, Italy. converti@unige.it
authors: Attilio
authors: A
authors: Converti
authors: Patrizia
authors: P
authors: Perego
authors: Andrea
authors: A
authors: Sordi
authors: Paolo
authors: P
authors: Torre
mesh_terms: D018533:Biomass; D002244:Carbon / Q000032:analysis / Q000378:metabolism; D002245:Carbon Dioxide / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004579:Electron Transport / Q000502:physiology; D005285:Fermentation / Q000502:physiology; D007700:Kinetics; D004718:Saccharomycetales / Q000254:growth & development / Q000378:metabolism*; D013379:Substrate Specificity; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D014994:Xylose; D014993:Xylitol