XANTHAN PRODUCTION IN AN EXTERNAL CIRCULATION LOOP AIRLIFT FERMENTER

A preliminary study of xanthan production by Xanthomonas campestris was performed in an external-circulation-loop airlift (ECL-AL) fermenter. An average of 25 g/L xanthan of good viscosity characteristics was obtained in a total fermentation time of 49 hours. Oxygen limitation was observed after 36 hours of fermentation time. It is conclusively demonstrated that the ECL-AL fermenter can be used to economically produce xanthan. The key operating and design features are the liquid height, downcomer-to-riser cross-sectional area ratio (A(D)/A(R)) and the orfice diameter of the air sparger.