The fermentation kinetics for the conversion of rice straw hemicellulosic hydrolysate to xylitol by the yeast Candida guilliermondii was evaluated under batch conditions. The fermentation was accomplished in a 1 L working volume stirred-tank reactor with aeration of 1.3 vvm and agitation of 300 rpm (k(L)a = 15/h). The maximum specific rate of xylitol formation (0.12 g/g) was achieved when the specific growth rate was lowered to 1/5 of its highest value. From analysis of the fermentation kinetics, a linear correlation between specific growth rate (mu(x)) and specific rate of xylitol formation (q(p)) was evident. Based on the Gaden model, this bioprocess was classified as growth-associated production and the relationship between mu(x) and q(p) can be described by the equation q(p) = 6.31 mu(x).