Enhanced production of β-glucan from Botryosphaeria rhodina using emulsified media or fan impellers

In this work the production of an extra-cellular β-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° 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 β-glucan concentration (18.7 ± 0.3 kg m−3), and yield coefficients for β-glucan on mycelial biomass formed (5.1 ± 0.8 g g−1) and specific power consumed (23.3 ± 0.4 g W−1).