Xanthan obtained from the broth at the end of fermentations under the whole range of stirrer speeds, was assayed for its pyruvate content. The trend in the pyruvate content with respect to stirrer speed is illustrated in Fig. 9. A dependence appears to exist between agitation and the degree of pyruvilation of xanthan. There is no significant difference in the pyruvate content of 300, 400 and 600 rpm (it ranged between 3 and 3.49%), while the effect becomes more pronounced when pyruvate of 100 rpm was compared with that of 600 rpm (1.54% at 100 rpm and 3.49% at 600 rpm). The increase of rpm from 200 to 300 influenced strongly the degree of pyruvilation of xanthan and as discussed earlier, it also influenced strongly xanthan production (Fig. 3).