Xanthan gum produced by Xanthomonas campestris from cheese whey: production optimisation and rheological characterisation

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 degrees 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 degrees C with 30 g L-1 gum. The use of CaCl2 resulted in the highest solution viscosity under conditions of 25 degrees 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. (C) 2009 Society of Chemical Industry