[Production of xanthan gum in immobilized cultures of Xanthomonas campestris]

The efficiency of xanthan production through surface processes was evaluated. The best porous material was selected first. Thereafter, a comparative study was performed using submerged agitated process vs other without agitation but containing the selected porous material. The culture medium used was white potatoes infusion, buffered with K2HPO4 and supplemented with glucose in diverse concentrations. Besides, to evaluate a different type of surface process, three vegetables were valued: Ipomaea batatus, Solanum tuberosum and Daucus carota, with an without glucose supplement. Larger xanthan production was achieved with immobilization of X. campestris vs the conventional method, when the liquid culture medium was used. The highest yield was obtained when the white potatoes infusion was supplemented with glucose 2.5%, yielding a conversion of this saccharide to xanthan up to 58%. When X. campestris was cultured on fragmented vegetables, the highest xanthan gum yield (5.6g) was obtained with Solanum tuberosum supplemented with glucose. This yield indicators that X. campestris used the glucose added as well as the constitutive polysaccharide of this vegetable.