Effect of phosphate buffer concentration on the batch xylitol production by Candida guilliermondii.
OBJECTIVE
To evaluate the effect of phosphate buffer concentration on growth and xylitol production by Candida guilliermondii FTI 20037.


RESULTS
Fermentations runs were carried out in batch mode employing semisynthetic medium supplemented with phosphate buffer at different concentrations (from 200 to 600 mmol l(-1)). The xylitol yield (Y(P/S)) and volumetric productivity (Q(P)) were improved when the fermentation medium was supplemented with phosphate buffer at concentration of 600 mmol l(-1). Under this condition (Y(P/S)) and (Q(P)) values were 0.75 g g(-1) and 0.66 g l(-1) h(-1), respectively, whereas in the absence of the phosphate buffer these values decreased to 0.52 g g(-1) and 0.44 g l(-1)h(-1) respectively.


CONCLUSIONS
The use of phosphate buffer at 600 mmol l(-1) promoted an easier pH control during shake flasks fermentation of C. guilliermondii. In addition the xylitol yield and productivity were significantly improved in response to the supplementation of potassium phosphate in the medium. The increase in these parameters could be related to both osmotic effect and pH control.


CONCLUSIONS
This approach provided a method for improving the xylitol production from semisynthetic medium by C. guilliermondii, being possible their use as a simple strategy to achieve efficient fermentation processes employing complex medium such as lignocellulosic hydrolysates.
Cortez
D V
DV
Department of Biotechnology, College of Chemical Engineering of Lorena, São Paulo, Brazil.
Roberto
I C
IC
D018533:Biomass; D002021:Buffers; D002175:Candida / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000494:pharmacology*; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism
D002021:Buffers; D010710:Phosphates; D014994:Xylose; D014993:Xylitol