No increases in exopolysaccharide (EPS) yields in Aureobasidium pullulans were observed when grown with reduced-shear impellers instead of standard Rushton turbines in the same vessel. However, yields were dramatically reduced when the organism was grown in an airlift reactor. This fall in production could be counteracted by improving fluid circulation through the placement of impellers within the draught tube, a strategy that resulted in the highest EPS concentration (approx. 13 g l(-1)) of all the fermenter configurations tested.