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BACKGROUND: This aim of this study was the production and rheological characterisation of xanthan gum by Xanthomonas campestris pv. mangiferaeindicae IBSBF 1230 using industrial media and experimental design techniques in a bench bioreactor. RESULTS: The optimised conditions for the production of xanthan starting with 900 mL of cheese whey were 1 g L−1 magnesium sulphate, 20 g L−1 potassium phosphate, 28 °C temperature and initial pH 7.2 at 390 rpm agitation and 1.5 vvm aeration, resulting in 36 g L−1 gum in 72 h. The highest viscosity obtained in the production optimisation study was 1831.34 mPa s at 25 °C with 30 g L−1 gum. The use of CaCl2 resulted in the highest solution viscosity under conditions of 25 °C, 1 g L−1 salt and 46.8 g L−1 gum, with a value of 1704.53 mPa s. CONCLUSION: In this study, cheese whey, a by-product of the dairy industry, was used as substrate in the production of xanthan gum, a valuable product in food applications, with optimised high gum production in a bioreactor and a wide range of viscosity values. Copyright © 2009 Society of Chemical Industry

This work is focused on hybrid modeling of xanthan gum bioproduction process by Xanthomonas campestris pv. mangiferaeindicae. Experiments were carried out to evaluate the effects of stirred speed and superficial gas velocity on the kinetics of cell growth, lactose consumption and xanthan gum production in a batch bioreactor using cheese whey as substrate. A hybrid model was employed to simulate the bio-process making use of an artificial neural network (ANN) as a kinetic parameter estimator for the phenomenological model. The hybrid modeling of the process provided a satisfactory fitting quality of the experimental data, since this approach makes possible the incorporation of the effects of operational variables on model parameters. The applicability of the validated model was investigated, using the model as a process simulator to evaluate the effects of initial cell and lactose concentration in the xanthan gum production.