Effects of initial pH on biological synthesis of xylitol using xylose-richhydrolysate

Sugarcane bagasse, an agricultural residue plentiful in Brazil, was utilize d for xyli tol production by a bio technological process. A medium fermenta tion prepared with this xylose-rich biomass at an oxygen transfer volumetri c coefficient of 10/h(1) and different initial pH values was inoculated wit h cells of Candida guillieirmondii FTI 20037. The maximum values of xylitol and cell volumetric productivities (Q(p) = 0. 56 g/[L.h] and Q(x) = 0.11 g/[g.h]), xylitol yield factor (Y-p/s = 0.79 g/g ), and xylose uptake rate (qs = 0.197 g/[g.h]) were attained at pH 7.0 with out further pH control. The results show that the yeast performance was inf luenced by the pH, an important bioengineering parameter in this fermentati on process.