Process of producing conventional or non-viscous xanthan by action of xanthomonas campestrisCNCM 1-956

A process of producing non-viscous xanthan, an aqueous solution of which at a concentration of 10 g/l has a viscosity of less than 700 mPa.s at 25.degree. C., which comprises cultivating Xanthomonas campestris CNCM I-956 in a nutrient medium containing 50 to 500 mg/l of an alkali metal hexametaphosphate and 1 to 15 mg/l of calcium ions and stopping the culture when the viscosity of the medium increases, wherein 50 to 200 mg of an alkali metal hexametaphosphate per liter of medium are introduced into the fermentation broth when the viscosity of the fermentation medium begins to increase.