Oxygen transfer during batch cultivation in an airlift tower fermentor

Oxygen transfer was studied in an airlift tower fermentor with motionless mixers (Kenics type). The intensity of oxygen transfer was characterized by its volumetric mass transfer coefficient, kLa, which was determined by the balance method. Experimental data of kLa were described by correlation equation and compared with results obtained for the airlift fermentor without motionless mixers with respect to energetic consumption. In addition, growth characteristics of the yeast culture Turulopsis ethanolitolerans cultivated on ethanol were also investigated.

Production of biomass from sulphite liquors in tower fermentor with forced circulation

Cultivation of the yeast Candida utilis on sulphite liquors was studied in a tower fermentor with ejector-type gas distributor and additional bubble bed showering. The aim of the work was to test the fermentor applicability for the cultivation process studied and to obtain data characterizing the fermentation in the tested unit. The effect of medium composition and dilution rate on selected cultivation parameters was determined in the fermentor with active volume 0.1 m3 and the hydrodynamic and energy characteristics of the apparatus were evaluated. The experimental results proved the fermentor to be suitable for the cultivation process studied. Favourable effect of the optimized fermentation medium was observed both on the values of characteristic cultivation parameters and on the efficiency of the utilization of energy supplied to the system.