AbstractXanthan biopolymer has been produced by single‐stage continuous fermentation withXanthomonas campestrisNRRL B‐1459 in a medium of glucose, minerals, distillers' solubles, and urea for as long as 20 days. At the highest dilution rate studied (D = 0.0285 hr−1), the steady state rate of xanthan production was 0.36 g/kg/hr and the steady state yield, basis glucose consumed, was 68%. Observations indicate that xanthan production rate is a function of pH