Xanthan production by Xanthomonas campestris NRRL B-1459 and interfacial approach by zeta potential measurement

Abstract

Dissociation of cell growth and metabolite production allows the creation of continuous reactors where conversion yields of carbon to product are very high. This is especially true for products such as xanthans, where physical parameters change rapidly, especially viscosity. At pH 5, cell growth and biomass production are increased. At pH 7, the opposite situation is observed, xanthan production is increased. Moreover, production is promoted at 30°C, while 25°C is the optimum temperature for cell growth. The composition of the medium (nitrogen source, citrate concentration, d -glucose concentration) has also been studied. Two-stage fermentation is an effective method, yielding up to 90% in the bioconversion of 1% d -glucose to xanthan. The xanthan/cell ratio is ∼10. The major difficulty in carrying out continuous production is the anionic characteristics of the gum.