The purpose of this work was to investigate the effects of xylose concentration (So = 50.0 to 275.0 g L-1) and glucose/xylose ratio (Sg/Sx = 0.09, 0.25 and 0.50) on the fermentative behavior of Debaryomyces hansenii UFV-170. The maximum cell productions expressed as cell dry weight were 40.28 g L-1 on pure xylose (Sx=106.30 g L-1) and 31.29 g L-1 on the glucose/xylose mixture (Sg = 5.0 g.L-1/Sx = 50.0 g L-1). The highest xylitol concentration (PXyt=130.43 g L-1) was obtained at Sx = 190.0 g L-1 corresponding to a xylitol yield (YXyt/S) of 0.77 g g-a, volumetric productivity (QXyt) of 0.54 g L-1 h-1 and specific productivity (qXyt) of 0.16 mmol g-1 h-1. High xylose levels (Sx≥187.0 g L-1) did not increase xylitol accumulation, but stimulated ethanol production. An increase in Sg/Sx ratio from 0.09 to 0.25 enhanced xylitol production at Sx = 50.0 g L-1, but not at Sx = 100.0 g L-1. In the simultaneous presence of glucose and xylose, PXyt=36.54 g L-1 was observed for Sg = 14.0 g L-1/Sx 50.0 g L-1 with YXyt/S=0.72 g g-1, QXyt=0.36 g L-1 h-1 and qXyt=0.08 mmol g-1 h-1. At the evaluated glucose/xylose ratio, glycerol and ethanol were formed as by-products
Influence of xylose concentration and glucose/xylose ratio on fermentation by Debaryomyces hansenii UFV-170
CONVERTI, ATTILIO
2011-01-01
Abstract
The purpose of this work was to investigate the effects of xylose concentration (So = 50.0 to 275.0 g L-1) and glucose/xylose ratio (Sg/Sx = 0.09, 0.25 and 0.50) on the fermentative behavior of Debaryomyces hansenii UFV-170. The maximum cell productions expressed as cell dry weight were 40.28 g L-1 on pure xylose (Sx=106.30 g L-1) and 31.29 g L-1 on the glucose/xylose mixture (Sg = 5.0 g.L-1/Sx = 50.0 g L-1). The highest xylitol concentration (PXyt=130.43 g L-1) was obtained at Sx = 190.0 g L-1 corresponding to a xylitol yield (YXyt/S) of 0.77 g g-a, volumetric productivity (QXyt) of 0.54 g L-1 h-1 and specific productivity (qXyt) of 0.16 mmol g-1 h-1. High xylose levels (Sx≥187.0 g L-1) did not increase xylitol accumulation, but stimulated ethanol production. An increase in Sg/Sx ratio from 0.09 to 0.25 enhanced xylitol production at Sx = 50.0 g L-1, but not at Sx = 100.0 g L-1. In the simultaneous presence of glucose and xylose, PXyt=36.54 g L-1 was observed for Sg = 14.0 g L-1/Sx 50.0 g L-1 with YXyt/S=0.72 g g-1, QXyt=0.36 g L-1 h-1 and qXyt=0.08 mmol g-1 h-1. At the evaluated glucose/xylose ratio, glycerol and ethanol were formed as by-products
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