In this work the production of an extra-cellular beta-glucan by Botryosphaeria rhodina DABAC P82, previously studied in a conventional bench-top stirred bioreactor, was enhanced by resorting to two different strategies consisting of dispersing different volumetric fractions of paraffin oil into the culture broth or replacing the six flat-blade Rushton turbines with 45 degrees pitched four-blade open style (fan) turbines with different impeller-to-vessel diameter ratios (D/T). Use of fan turbines with D/T= 0.54 at a tip impeller speed of 1.4 m s(-1) resulted in less viscous culture broths and most advantageous values of the beta-glucan concentration (18.7 +/- 0.3 kg m(-3)), and yield coefficients for P-glucan on mycelial biomass formed (5.1 +/- 0.8 g g(-1)) and specific power consumed (23.3 +/- 0.4 g W-1). (c) 2006 Elsevier Inc. All rights reserved.