The aim of this work was to study how media rheology and bioreactor hydrodynamics would influence fermentation of lignocellulosic and starch-based substrates under pseudoplastic flow conditions. This was investigated using hydrolyzed wheat straw, wheat-based thin stillage and filamentous fungi as inoculum in bubble column, airlift and horizontal hybrid tubular/bubble column (textile bioreactor) bioreactors. The rheological models showed that the consistency index was dependent on biomass growth (R-2 0.99) while the flow behavior index depended on biomass growth and suspended solid (R-2 0.99). Oxygen transfer rate above 0.356 mmol-O-2/L/h was needed for growing fungi with a cube-root growth rate constant of 0.03 g(1/3)/L-1/3/h. At 1.4 VVM aeration the textile bioreactor performed better than others with minimal foaming, yields of 0.22 +/- 0.01 g/g and 0.47 +/- 0.01 g/g for ethanol and biomass, substrate consumption rate of 0.38 g/L/h. Operating the bioreactors with air-flowrate to cross-sectional area ratio of 8.75 x 10(-3) (m(3)/s/m(2)) or more led to sustained foaming.